Advances in Parasitology Volume 12

Advances in PARASITOLOGY

V O L U M E 12

This Page Intentionally Left Blank

Advances in

PARASITOLOGY Edited by

BEN DAWES Professor Emeritus, University of London

V O L U M E 12

1974

ACADEMIC PRESS London and New York

ACADEMIC PRESS INC. (LONDON) LTD. 24/28 Oval Road, London NWl 7DX United States Edition published by ACADEMIC PRESS INC. 11 1 Fifth Avenue New York, New York lo003

Copyright 0 1974 by ACADEMIC PRESS INC. (LONDON) LTD. Second printing 1975

All Rights Reserved

No part of this book may be reproduced in any form by photostat, microfilm, or any other means, without written permission from the publishers Library of Congress Catalog Card Number: 62-22124 ISBN : 0-1 2-03 17 12-5

Printed in Great Britain by Galliard (Printers) Limited. Great Yarmouth

CONTRIBUTORS TO VOLUME 12 SHERWIN S. DESSER, Department of Parasitology, School of Hygiene, University of Toronto, Toronto, Canada (p. 1 ) A. MURRAY FALLIS,Department of Parasitology, School of Hygiene, University of Toronto, Toronto, Canada (p. 1 ) 6

WAFTALE KATZ,Centro de Pesquisas “Renk Rachou”, Instituto de Endemias Rurais and Instituto de Cigncias Bioldgicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil ( p . 369) RASULA. KHAN, Department of Biology, Memorial University of Newfoundland, St. John’s, Canada (p. 1) D. F. METTRICK, Department of Zoology, University of Toronto, Toronto, Ontario, Canada (p. 183) J . F. MICHEL,Central Veterinary Laboratory, Weybridge, Surrey, England (P.279) *J. PELLEGRINO, Centro de Pesquisas “RenP Rachou”, Instituto de Endemias Rurais and Instituto de Ci2ncias Bioldgicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil (p. 369)

WALLACE PETERS,Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, England (p. 69) R. B. PODESTA,Department of Zoology, University of Toronto, Toronto, Ontario, Canada (p. 183)

M. A. STIREWALT, Biomedical Research Institute, American Foundation for Biological Research, 121 1 1 Parklawn Drive, Rockville, Maryland 20852, U.S.A. (p. 115)

* Authors in the section “Short Review”

This Page Intentionally Left Blank

PREFACE This book of the series has been brought down to previously maintained size following the enlarged effort of volume 11 which marked the exuberant opening of a second decade. This time there are six reviews, one of them an updated short, by ten parasitologists working in Brazil, Britain, Canada and U.S.A. Writing on species of Leucocytozoon, A. Murray Fallis, Sherwin S. Desser and Rasul A. Khan mention the “informed reviews” on avian Haemosporidia by Clay G . Huff, one of which opened this series of books and the other an updated review in Vol. 6 (1968). They also indicate that increasing interestin these protozoan organisms calls for further comment, which they have made in terms of intimate knowledge of their nature, biology and transmission, and of their effects on their hosts. It would be futile here to try to summarize the great wealth of facts and ideas they present, bearing on the prevalence, taxonomy, life cycles, ultrastructure, pathogenesis and pathology of these avian blood parasites, together with treatment in terms of prevention and control, immunity and cultivation. Progress has been made in our knowledge of these parasites but there is uncertainty about some of the many “species” and difficulties concerning life cycles, the experimental study of which demands satisfactory methods of maintaining hosts and vectors. In the past, cytology and genetics have been somewhat neglected and it is not sufficiently admitted that the use and study of such organisms as these serve, as they do, to help our understanding of many problems of cell biology. They claim that interest in some matters concerning Leucocytozoon and related coccidian and malarial parasites should lead to further advances in the future. As Editor, I would like to a d d . . . as did the review on Toxoplasma and toxoplasmosis by Leon Jacobs in “Advances in Parasitology”, Vol. 5 (1967), the proof being in the updated review in Vol. 11 (1973). Wallace Peters has been concerned with the complementary subject of antimalarial chemotherapy and drug resistance. His review also is packed closely with facts and ideas gleaned from his own experiences and other research efforts that in the last decade, we are told, were greater than those of the previous half century. In an informative Introduction we learn that Plasmodium falciparum is the only species of parasite of importance to man that has developed significant resistance to chloroquine and antifols (dihydrofoliate reductase inhibitors). Most of the chemotherapy during the past decade has been directed against strains of this kind, more than one quarter of a million compounds having been screened for antimalarial action in vivo. Chloroquine resistance in Plasmodium falciparum, the agent of malignant tertian malaria, “is spreading faster than malaria control or eradication can keep up with the transmission of this parasite”. Again, it is impossible here to try to summarize the amount of detail provided for the interested reader, facts and ideas concerning newer techniques for drug-testing, the mode of action of antimalarial vii

...

Vlll

PREFACE

drugs, drug-parasite-host interactions, mechanisms of drug resistance, and new anti-malarial drugs and drug combinations. Our future outlook makes necessary mention of the fact that global malaria eradication has been set back during the past few years and that revised strategy has been necessary. The work of Leonard J. Bruce-Chwatt is mentioned along with that of many other experts, and it would be remiss of me not to mention that the reference to his review in this series (Vol. 1I , 1973) on global problems of imported disease was added by me because it was not available to Wallace Peters when it was “in the press”. Margaret A. Stirewalt has made a forthright study of the cercaria-schistosomule development of Sclzistosomamansoni, a field of research in which she has abundantly qualified herself. The cercariae live for some time within a sporocyst in the molluscan host, ultimately escaping and living in the snail’s tissues for a brief period and then breaking out into a freshwater environment, impelled then to seek a vertebrate host and penetrate by way of the skin into its tissues, thus reverting to a parasitic habit. These changes of milieu take no more than a few days of unsettled existence but produce dramatic and important adaptations, which are here carefully assessed. The characteristic features of embryonic and emerged cercariae and of schistosomules are then closely compared and contrasted in respect of tegument, glycocalyx and tegumentary spines, sensory papillae, nerves and muscle, secretory cells, digestive and excretory systems, enzymes and metabolism. Next follow passages on methods of collecting schistosomules through host skin, in vitro through penetrable membranes, after unsuccessful attempts at penetration, and under other conditions. Criteria for schistosomules are tabulated and compared in respect of a score of differential characteristics. Finally, conversion mechanisms concerned with the transformation from cercaria to schistosomule are discussed, and it is considered that at least two elements are essential. One is a “trigger” for initiating such change as occurs, and the second is a means of support for the transforming young schistosomes in a “culture environment” which fosters them during the period of ensuing changes. At present, background information is insufficient in detail and amount but a start has been made here to identify “triggers” and mechanisms involved in the change from cercaria to schistosomule, and possibly “in the larger context of a comparison of the modus vivendi of free-living and parasitic organisms”. The review of David F. Mettrick and Ronald B. Podesta is concerned with the interaction of helminths and their hosts within the alimentary canal and especially the stomach and intestines, the “most favoured niche” for digenetic trematodes, cestodes, acanthocephalans and nematodes. Many such parasites live in the gastro-intestinal canal, while others penetrate into the wall of the canal and a few invade organs such as the liver and pancreas. Attention has been confined to mammalian hosts for several stated reasons, one of which is early presentation of a complementary review dealing with avian hosts and their parasites by other colleagues in a future book of this series. Constrained as they are, these writers have made a deep study that not only deals adequately with the parasites but also provides much valuable information on the ecological background within the host’s body. This is something of a novelty

PREFACE

ix

in the literature, but the dynamic relationship between parasite and host is clearly shown and a good example set for future researchers. First, there is a study of the parasite-host interface, including the various kinds of organs of attachment, the varied nature of the lumen and the mucosa of the gastrointestinal canal, the nature of adhesion, and absorptive surfaces of the helminth and the host. Then come sections dealing with the ecology of helminth site selection by trematodes, cestodes and nematodes, and matters concerning concurrent infections, transplantation and migration. One section deals with the chemical and physical characteristics of the intestinal lumen ionic and osmotic characters, microbial ecology, enzymes, bile acids and dietary fats, nutritive gradients and matters of luminal homeostasis. Another section deals with functional gradients in the gastrointestinal tract, bearing on the absorption of electrolytes and non-electrolytes, water absorption and malabsorption. Such a catalogue of contents does little justice to the great effort made by the writers to correlate or at least to put side by side the physiological nature of parasite nutrition and the physico-chemical background against which parasites have to act. The mechanisms involved in the parasite’s quest for nutriment and the host’s reactions to these demands are extremely complex stimuli and responses, and the rareness of attempts to elucidate these problems is related to the difficulties of representing such dynamic relationships as are better understood by many parasitologists after reading and studying this review. J. F. Michel is concerned with the fascinating subject of arrested development in nematode parasites. He explains in his Introduction that many parasitic nematodes have a resting stage or stages, further development depending on the reception of some stimulus or stimuli. This pause in development at some precise point in the life cycle of the parasite occurs only in certain hosts or circumstances or at certain times of the year, and it affects only some of the roundworms. Because of differences as well as similarities in details, Michel prefers not to discuss arrested development as if it were identical in all host-parasite systems. Instead, he chooses to deal with parasitic genera and species within nine families, more than 30 genera and many more species helping to build up as complete a general picture as is possible at the present time. Then, in an ultimate section similarities and differences are discussed. Such a long and reasoned discussion cannot possible be summarized in a few lines. Some sections of the review tend to show that evidence for a direct effect of immunity or of size of infection on arrested development is still not convincing although host resistance may be crucial in some systems. Another view is that arrested development serves to synchronize the life cycle of the parasite either with that of the host or else with seasonal changes in the external environment, and it implies a response to signals either to halt development, or to cause it to be resumed, or to serve both functions. It appears to me that this review on arrested development shows some relationship with the previous review and further studies will require an approach to fundamental characteristics to a greater extent than is evident in previous researches. Both reviews are dealing basically with a complex and dynamic system of signals and responses in both the parasites and the hosts.

X

PREFACE

The review by Naftale Katz and JosC Pellegrino is an updated statement on experimental chemotherapy of schistosomiasis mansoni, furthering what was written by these authors (as J. P. and N. K.) in Volume 6 of this series (1 968). In their Introduction and in relation to their previous review, these authors state that during the past 5 years rewarding progress has been made, notably in that one drug (hycanthone) is being used widely in endemic areas, while another drug (oxamniquine) is now gaining prominence as a promising schistosomicidal agent. We are told that the quest for new drugs in both chemoprophylaxis and chemotherapy is in progress, and that stress is being laid on the selective rather than on the empirical approach, allowing the development of hycanthone starting from Miracil D and of oxamniquine from the mirasan series of drugs. The review is intended to be selective and not exhaustive, dealing mainly with trials using these two drugs. However, much has been done about the physiology and biochemistry of Schistosoma mansoni and after giving us a section on new experimental hosts and screening techniques Katz and Pellegrino give us a section on this vital subject. This is followed by a section dealing with new antischistosomal agents, miscellaneous schistosomicides and egg suppressants and chemosterilants. Many readers will be well satisfied with the contents of this short review, which is a finely concentrated abundance of new and always modern information. Once again I am glad to say thank you to a small group of friends and colleagues who have provided a cluster of well documented reviews that extend towards the limit of existing knowledge in the field of parasitology and who have thus helped me towards fulfilment of my avowed aim at the outset of my efforts to produce Advances in Parasitology. I am equally grateful and offer my thanks also to members of staff of Academic Press for the valuable assistance they have given during the actual production of this book, hoping that they too may feel they have supported a worthy cause. BEN DAWES Professor Emeritus: University of London May, 1974 “Rodenhurst”, 22 Meadow Close? Reedley, Burnley, Lancs. BBlO ZQU, England

CONTENTS CONTRIBUTORS TO VOLUME 12 ............................................................ PREFACE.......................................................................................

V

vii

On Species of Leucocytoaoon .

.

A MURRAY FALLIS. SHERWIN S. DESSER AND RASUL A KHAN

I. Introduction

...........................................................................

I1. Prevalence .............................................................................. III. Taxonomy ..............................................................................

4 21 35 47 50 50 51 52 52 52 67

1V. Life Cycles ........................................................................... V. Ultrastructure ........................................................................ ...................................................... VI Pathogenesis and Patho logy VII . Treatment .............................................................................. VIII . Immunity .............................................................................. IX. Cultivation ......... ................................................................. X. Summary .............................................................................. Acknowledgements .................................................................. References .............................................................................. Addendum ..............................................................................

.

Recent Advances in Antimalarial Chemotherapy and Drug Resistance WALLACE PETERS

1. Introduction

...........................................................................

69

11. Newer Techniques for Drug Testing .............................................

III. Mode of Action of Antimalarial Drugs ....................................... IV . Drug-ParasiteHost Interactions ................................................ V. Mechanisms of Drug Resistance ................................................ VI . New Antimalarial Drugs and Drug Combinations ........................... VII. Tomorrow's Outlook ............................................................... References ..............................................................................

71 75 89 89 97 105 106

Schistosoma mansoni: Cercaria to Schistosomule

. .

M A STIREWALT

I. Introduction ........................................................................... 11. General Considerations ............................................................ 111. Tegument .............................................................................. IV. Glycocalyx .............................................................................. V. Tegumentary Spines .................................................................. VI. Sensory Papillae ..................................................................... VIT Nervous System ..................................................................... VIII. Musculature ........................................................................... IX. Secretory Cells ........................................................................ X . Digestive Tract ........................................................................ XI . Excretory System ..................................................................... XII. Enzymes .................................................................................

.

xi

115 116 121 125 128 129 132 133 135 144 146 149

xii

CONTENTS

XI11. Metabolism ........................................................................... XIV. Methods of Collecting Schistosomules .......................................... XV . Criteria for Schistosomules ......................................................... XVI. Cercaria to Schistosomule Conversion Mechanisms ........................ References ..............................................................................

154 157 165 170 175

Ecological and Physiological Aspects of HelminthHost Interactions in the Mammalian Gastrointestinal Canal D . F . METTRICK AND R . B . PODESTA I. Introduction ........................................................................... 183 I1. The Parasite-Host Interface ...................................................... 184 I11. Ecology of Helminth Site Selection ............................................. 191 IV . Chemical Characteristics of the Intestinal Lumen ........................... 206 V . Functional Gradients in the Gastrointestinal Tract ........................ VI . Conclusions ........................................................................... Acknowledgements .................................................................. References ..............................................................................

231 248 249 249

Arrested Development of Nematodes and some Related Phenomena J . F . MICHEL 280 I. Introduction ........................................................................... 281 I1. Dictyocaulidae. Heligmosomatidae ............................................. I11. Trichostrongylidae .................................................................. IV . Trichonematidae ..................................................................... V. The Spring Rise ..................................................................... VI . Ancylostomatidae ..................................................................... VII . Strongyloididae ........................................................................ VIII . Ascaridae .............................................................................. IX . Heterakidae ........................................................................... X . Spiruridae .............................................................................. XI . Discussion .............................................................................. References ..............................................................................

284 307 312 322 326 328 336 336 337 343

SHORT REVIEW Supplementing Contribution to a Previous Volume Experimenta1 Chemotherapy of Schis tosomiasis mansoni

.

NAFTALE KATZ AND J PELLEGRINO

I . Introduction ........................................................................... I1. New Experimental Hosts and Screening Techniques ........................ 111. Biochemistry and Physiology of S. mansoni ................................. IV. New Antischistosomal Agents ................................................... References ..............................................................................

Authors Index .............................................................................. Subject Index ..............................................................................

369 370 371 374 384 391 417

On Species of Leucocytozoon A. MURRAY FALLIS,

SHERWIN S. DESSER

Department of Parasitology, School of Hygiene, University of Toronto, Toronto, Canada AND

P A W L A. KHAN

Department of Biology, Memorial University of Newfoundland, St. John’s, Canada I. 11. 111. IV. V. VI. VII. VIII. IX. X.

Introduction .................................................................................. Prevalence ..................................................................................... Taxonomy ..................................................................................... Life Cycles ..................................................................................... Ultrastructure.................................................................................. Pathogenesis and Pathology................................................................ Treatment ..................................................................................... Immunity........................................................................................ Cultivation ..................................................................................... Summary ........................................................................................ Acknowledgements ......................................................................... References....................................................................................... Addendum ..............................................................

1 3 4 21 35 41 50 50 51 52 52 52 67

I. INTRODUCTION Informed reviews by Huff (1963, 1968) on avian Haemosporidia in earlier volumes of this series included useful summaries on species of Leucocytozoon. Although questions he posed remain unanswered, an increasing interest in these organisms suggests that further comments would be welcome. It is hoped that the following summary of knowledge of these parasites, their biology, transmission and effects on their hosts will stimulate studies which are obviously required for a better understanding of all species. Danilewsky (1889, 1890) described and illustrated, but did not name, a species in an owl. The idea for the generic name undoubtedly came from him as he wrote, “Mais la forme et la dimension du noyau, de la capsule, l’absence de grains de melanine, la dimension et l’aspect de la membrane capsulaire, tout ceci parle en faveur du developpement des ces parasites intracellulaires dans les globules blancs du sang-ergo ce sont des Leucocytozoa (par analogie aux Hemacytozoa)”. He referred to these parasites collectively as “leucocytozaires” although later he decided (1890) some were located in erythroblasts. The generic name Leucocytozoon appears to have been used for the first time by Berestneff (19O4), who redescribed the species which Ziemann (1898) 1

2

A . M U R R A Y EALLIS, S H E R W I N S . DESSER A N D R A S U L A . K H A N

studied in the little owl and referred to as Leucocytozoon danilewskyi. Subsequently Laveran described (1903) Haenzamoeba ziemanni from owls, but in our opinion and that of Hsu et al. (1973) it is a synonym of the type species. Invention of the Romanowsky stain facilitated study of these and other haematozoa and more than half of the named species of Leucocytozoon from birds were described before 1920. A single species, L. giovannolai, the description of which we were unable to obtain, has been described in the last 20 years. A similar parasite, Saurocytozoon tupinambi, described from lizards by Lainson and Shaw (1969), is considered by Hsu et al. (1973) to represent a subgenus of Leucocytozoon. Paraleucocytozoon lainsoni, described by Arcay-Peraza (1 968) from lizards, may be a haemogregarine. Parasites of mammals that were placed incorrectly in the genus are noted by Wenyon (1926), Coatney (1937) and Hsu et al. (1973). Uncertainty among early observers concerning the classification of these organisms is not surprising. Schaudinn (19.04) and others (Cleland and Johnston, 1911) linked them initially with trypanosomes. Rodhain et al. (1913) stressed the necessity of knowing the life cycles to decide the families and genera in which the parasites should be placed. The presence or absence of chromophilic granulations was regarded as a specific character by Franqa (1912) when he described L. mirandae. This is of questionable value because granulations are not always apparent. Wenyon (1926) placed these organisms in the family Haemoproteidae, while others group them with the Plasmodiidae (Hsu et al., 1973). We believe that differences in morphology and life cycles justify placing the genus in a separate family, Leucocytozoidae, within the Haemosporina (Bennett et al., 1965) as proposed by Doflein (1916). Most species are known only by their stained gametocytes in smears of peripheral blood. Study of living specimens is complicated by the rapid change that may occur in the gametocytes held in a drop of blood. Criteria for distinguishing gametocytes are few-namely, size, staining characteristics, nature and extent of distortion of the cell in which they live, and the size, position and shape of its altered nucleus. Identification is more uncertain if the parasites are studied only in blood films prepared without reference to the life cycle. Mathis and LCger (1 912), and Ltger and LCger (1 914) believed the parasites should be divided into two groups on the basis of their occurrence in round or elongate cells. However, species such as L. simondi, L. bonasae and L. danilewskyi, occur in both types of cells at different times in their cycles. Our experience with these species indicates that only round gametocytes are present during early patency, elongate forms appear a few days later and both types are seen during periods of relapse. The suggestion of de Mello and Alphonse (1935) that the two types should be in different genera and that a new genus, Legerozoon, should be created for those species with round gametocytes is therefore unacceptable. Bennett et al. (1965) placed Leucocytozoon caulleryi in a new genus Akiba because, unlike other species, the nucleus of the invaded cell disappears as the gametocyte matures although the membrane around the cell appears intact. Moreover species of Culicoides rather than Simulium are vectors. Hsu et al. (1973) believe Akiba should be a subgenus and, contrary to an earlier opinion, we accept their view until its life cycle and those of other species are better

O N SPECIES OF L E U C O C Y T O Z O O N

3

understood. Mathis and Ltger (1909a) noted the absence of the nucleus in some of the blood cells of a francolin harbouring mature L. mesnili. The possibility that the bird was infected also with L. caulleryi cannot be excluded pending experimental cross-infections. 11. PREVALENCE

Species of Leucocytozoon are known from many kinds of birds throughout the world (Al-Dabagh, 1964; Aubert and Heckenroth, 1911; Baker, 1958; Beer, 1944; Bennett and Fallis, 1960; Berson, 1964; Boing, 1925; Borg, 1949; Bray, 1964; Breinl, 1913; Burgess, 1957; Clark, 1964; Clark and Swinehart, 1969; Clarke, 1938, 1946; Cleland, 1915, 1922; Cleland and Johnston, 1911; Coatney, 1937, 1960; Coatney and Jellison, 1940; Coatney and Roudabush, 1937; Coatney and West, 1938; Coles, 1914; Corradetti et al., 1941 ;Covaleda Ortega and Gallego Berenquer, 1946; De Lucena, 1941; Dorney and Todd, 1960; Dutton et al., 1907; Eide et al., 1969; Ewers, 1967; Fantham, 1910b, 1921, 1926, 1927; Fantham et al., 1942; Farmer, 1960; Frank, 1965, 1967; Frank and Kaiser, 1967; Galindo and Sousa, 1966; Gardiner and Wehr, 1949; Gaud and Petitot, 1945; Glushchenko, 1962; Goldsby, 1951; Hanson et al., 1957; Hart, 1949; Herman, 1938a, 1944, 1951; Hewitt, 1940; Hinshaw and McNeil, 1943; Hsu et al., 1973; Jansen, 1952; Johnston, 1912, 1916; Jordan, 1943; Kerandel, 1909, 1913; Kozicky, 1948; Kuppusamy, 1936; Laird, 1950, 1961; LCger, 1913; Ltger and Mathis, 1909; Levine, 1954, 1962; Levine and Hanson, 1953; Levine and Kantor, 1959; Love et al., 1953; Lubinsky et al., 1940; Mackerras and Mackerras, 1960; Manwell, 1951, 1955; Manwell and Herman, 1935; Mello, l935,1937a, 1937b; Morgan and Waller, 1941; NeIson and Gashwilder, 1941 ;Ogawa, 1912; Oliger, 1940; O’Meara, 1956; Oosthuizen and Markus, 1967a, 1967b, 1967c, 1968; Plimmer, 1913, 1914; Ramisz, 1962; Renjifo et al., 1952; Rodhain et al., 1913; Sachs, 1953; Sadun, 1949; Scott, 1926; Sergent and Sergent, 1905, 1907; Sewell, 1938; Simpson et al., 1956; Son, 1960; Stabler, 1961; Stabler and Holt, 1963; Takos, 1947; Tendeiro, 1947; Thompson, 1943; Todd and Wolbach, 1912; Trainer et al., 1962; Uegaki, 1930; Van den Berghe, 1942; Walker, 1912; Wetmore, 1941;Wohnus and Ryerson, 1941; Wood and Herman, 1943; Wood and Wood, 1937; Zajicek, 1968). References to some records may have been overlooked; others were not available to us. Difficulties of identification probably explain the absence of specific names in several reports. The above records do not necessarily indicate total distribution but rather places where observations have been made. Other endemic foci and additional hosts undoubtedly await discovery. Absence of vectors rather than unsuitability of the birds as hosts may explain the lack of records in some localities. In other places frequented by migratory birds, transmission may not occur for the same reason, although the parasites may be recorded. Absence of L. simondi and L. sakharoffi from the Avalon peninsula, Newfoundland, Canada, is interesting (Bennett and Laird, 1973) as both species occur elsewhere in Canada and in Scandinavia. Garnham (1954) and Mohammed (1958) reported low incidence in parts of Egypt where simuliids are scarce or absent, and Lainson et al. (1 970) reported a

4

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

similar situation in Brazil. The widespread distribution of species such as L. Sringiiiinarum contrasts with the more restricted distribution of species like L. caulleryi. A high incidence can be expected in owls and other nocturnally active birds as their quiescent habits until dark should favour transmission by simuliids. 111. TAXONOMY Many descriptions contain measurements of gametocytes to pm and occasionally T+a pm. Such refinement in distinguishing species is questionable as the variation in size among specimens in the same blood film is usually greater than this. Moreover, gametocytes seen in early patency may differ from those seen later. Variability in size and appearance makes identification difficult,especiallyif the blood film is from an unknown host. Future taxonomic studies could benefit from the WHO reference collection at Memorial University, St. John’s, Newfoundland (Bennett and Laird, 1973) especially if complementary studies on life cycles were feasible. Similarities in the appearance of gametocytes of several named species, and variation in morphology of the parasite and host cell within a species, suggest synonymy but dogmatic opinions are unwarranted until data on the life histories and on cross infections are available. As Bray (1964) stated, “Nomenclature among parasites is as much an experimental study as it is an observational study.and until this is realized this discipline will continue undisciplined.” The described species with a summary of their size and appearance as taken from the original descriptions are listed in Table I. These and the illustrations (Figs 1 4 2 ) to the same scale, mostly adapted from the original drawings and photographs suggest the synonymy indicated in Table I. The names of the birds are from Peters (1 931-70). Unfortunately Albanellapallida, the recorded host for L.laverani FranGa, is not listed. A. STRUTHIOFORMES AND PELECANIFORMES

L. struthionis and L. vandenbrandeniare the only species described from these orders of birds respectively. Although the gametocytes resemble other species FIGS. 1-42. Macrogametocytes of species of Leucocyfozoon drawn to the same scale. Unless stated otherwise, they are adapted from the illustrations of those who described the species as indicated in Table I. FIG.1.L.struthionis. FIG.2. L. vandenbrandeni. The distorted nucleus of the cell harbouring the parasite is probably abnormal. FIG.3. L. ardeae. FIG.4. L. iowense, probably a synonym of L. ardeae. FIG.5. L. bacelari. FIG.6 . L . simondi. The round type of gametocyte of this species is shown in Fig. 45. FIG.7. L. audieri. This species is reported also in round cells. FIG.8. L. circaeri. FIG.9. L. caulleryi. Gametocytes of this species are seen often in cells in which the nucleus is lacking. FIGS.10, 11. L. sabrazesi in a round and an attenuated cell. FIG.12. L. schoutedeni. The shape of the cells harbouring this species is rather variable. FIG. 13. L. andrewsi. FIG.14. L . mesnili. A gametocyte of this species resembling L. caulleryi is reported also. FIG.15. L. kerandeli. FIG.16. L . francolini. Similarity to L. kerandeli and to L . neavei suggests L . neavei is the senior synonym of each. FIG. 17. L. lovati. FIG.18. L . mansoni. FIG.19. L . bonosae. The last 3 species have similar gametocytes of variable size in round and elongate cells. They are probably synonymous with L . lovati the senior synonym. FIG.20. L. neavei. FIG.21. L. numidae. FIG.22. L. costae. We believe this species and L. numidae are junior synonyms of L . neavei. FIG.23. L. smithi. FIG.24. L. coccyzus.

O N SPECIES OF

L slrulhionis

2. vandenbrandeni

5

LEUCOCYTOZOON

3. ardeae

4. iowense

5 . bacelad

II sabrnresr

14 rnesnil

deni

24. coccyzus

13 andrewsi

6

A. MURRAY FALLIS, SHERWIN

25. euryslom,

s.

DESSER A N D R A S U L A . K H A N

26 euryslomi 27 corocioe

7 28 le,!oo, 29 sou-sodiosi

31 don,lewshy,

33 ziernonnr coprimulg,

-

36 sokhoroffr

37 IroMr,crs

30

majoris

35 bereslneff!

IOpm L

41 onellobroe

4 2 monordr

FIGS25,26. L. eurystomi is probably a synonym of L. neavei. FIG.27. L . coraciae. FIG.28. L. leitaoi. FIG.29. L. sou-sadiasi. FIG.30. L. dinizi. FIGS31,32. L. danilewskyi. Two shapes of cells and gametocytesare common and parasites occur in round cells also. FIG33. L. ziemanvi. We consider it a synonym of the type species L . danilewskyi. FIG.34. L. caprimulgi is believed to be a synonym ofL. danilewskyi. FIG.35. L. berestnefi, adapted from Wingstrand. FIG.36. L. sakharofi, adapted from Wingstrand. FIG.37. L. Iiothricis. FIG.38. L. majoris, adapted from Sambon. FIG.39. L. dubreuili, original.FIG.40. L. fringillinarum.FIG.41. L. annelobiae, adapted from Mackerras and Mackerras. Fig. 42. L . monari.

the names are retained pending more data on each. The latter species was reported also by Mackerras and Mackerras (1960) from the cormorant from Australia. B. CICONIFORMES

The description ofL. urdeolue is insufficient to separate it from other species. Coatney (1938) believed L. ioowennse could be distinguished from L. ardeue by

TABLE 1 Data on species of Leucocytozoon (measurements to nearest micrometre, means in parentheses) Order, family, species of host

Country

S. Africa

Struthioformes Struthionidae Struthio camelus Pelecaniformes Phalacrocoracidae Anhinga r. rufa =Plotus rufus Ciconiiformes Ardeidae Ixobrychus sinensis = Ardetta sinensis Ardea goliath

Congo

Ardeola grayi Butorides virescens

India U.S.A.

Congo

Species parasite struthionis

Author Walker, 1913

Shape and size female male Ra 11-15x 9-10 9-1 3

vundenbran- Rodhain, 1931 R 16 derii

11-14

Host cell

R R

Remarks

host nucleus cap-like host nucleus ++around

0

z

v1

2m S.E. Asia

leboeu$

Mathis and R 12 ZRger, 1911a

same

R

host nucleus around

+

VJ

1 P

h

c

Anseriformes S.E. Asia Anatidae Anus crecca = Querquedulla crecca Anseridae Europe Anser domesticus

Rodhain et aL, R 14-17 16x 17 1913 urdeolue de Mello, 1937a R iowense Coatney, 1938 R 11-17 x 8-13 10-14 x 10-13 (13 x 11) (13 x 11) simondi Mathis and E b 14-15 x 5-6 smaller =matis Lkger, 1910~R urdeue

anseris

Knuth and R 5-7 x 3-5 Magdeburg, 1922

0

R

0

R R

sp. inquir.c syn.d of urdeue

E 48 R

host nucleus 30 in length

R 13-15

syn. of simondi

0 Y Y

20

'

0

4

TABLE I (continued)

Order, family, species of host

Country

Falconiformes P. Guinea Accipitridae Kaup$alco rnonograrnmicus = Asturinulh monogrammica Falconiformes Congo Accipitridae Kaupifalco monogrammicus =Asturinulla monogrammica Congo Haliaetus vocifer Accipiter nisus Circaetusgallicus

Portugal Algeria

Accipiter badius Africa sphenurus = Astur badius sphenurus Falconidae Italy Albanella pallida

Species parasite bacelari

Author

00

Shape and size female male

Tendeiro, 1947 R12-14x10

10-13x9-11

Host cell

Remarks

R14-18x119 hostnucleus 13-17x 11- cap 3 around 12 l3

> ’

3

5 w > 4

crl

> r

toddi

Sambon, 1907/8

E 16-23 x 9-14

E 47-63

measurements Sambon, 1908

t:

“m

2

I

M

2

audieri mathisi circaeti martyi

Laveran and E 11-18 x 8-14 Nattan-Larrier, 1911 Franqa, 1912a Sergent and E 1 6 18 x 6 7 Fabiani, 1922 (from drawing) Commes, 1918 E 23 x 7 21 x 6

Y

E 36-40 E E 30 x 8-9

sp. inquir. host nucleus 10-13x3-5

U m m m

m

@

> 2

E 52-53

U

w >

m

laverani Franchini, E 14-20 x 6-10 7-8 x 4-5 homonym of 1923 L. laverani Franqa, 1912a renamed L. franchini Franqa, 1927

E 25-35

host cell except nucleus missing from many males

C r

>

.7;1 ?-

z

E 18-29 x 9-13 21-22 x 10-11 ( 2 4 . 0 ~11.3)

Sagittaridae Mozambique Sagittarius serpentarius

beaurepairei

Dias, 1951

Galliformes Phasianidae Phasianus colchicus Pavo cristatus

Britain

macleani

Sambon, 1908

S.E. Asia

martini

Gallus gallus

S.E. Asia

caulleryi

Gallus gallus

S.E. Asia

sabrazesi

Gallus gallus

Sumatra

schuffneri

Gallus gallus

Congo

schoutedeni

Gallus gallus Gallus gallus

Yugoslavia U.S.A.

galli andrewsi

Mathis and R 13-17 (15) Lkger, 1911a Mathis and R 16 Leger, 1909a Mathisand E15xf3-24x4 Leger, 1910a von Prowazek, E 1912 Rodhain et at., R 13 1913 Ivanic, 1937 R Atchley, 1951 R 12-14

Coturnix chinensis S.E. Asia = Francolinus sinensis

Francolinus sinensis S.E. Asia F. bicalcaratus

Congo

mesnili

LCger and R 12 Mathis, 1909

E 29-67 x 9-17 nucleus (47 x 12.5) 9 narrow band (39-45 x 1113) d sp. inquir.

11

R 15-18

< 16

R 20

24x3

E 67 x 6-34 $2 67 x 4-34 8 E syn. of sabrazesi R 18 host nucleus Haround R sp. inquir. R 15-17 9 host nucleus 13-15 3 narrow band R 1416 nucleus flattened to one side missing from some 39:ld E syn. of neavei round forms also E syn. of neavei R

host nucleus 3 around ld:39

0

z

cn

11 10-12 11

kerandeli

Mathis and E 16 x 8 LCger, 1911a

francolini

Kerandel, 1913 E 15-25 x 4 1 3 smaller R 5-11

m

cm cn

f;

c 0

0 0

a

2 0 2

-

TABLE I (continued)

Order, family, species of host

Country

Species parasite

Author

0

?

Shape and size female male

Host cell

Remarks

z A

Pternistis Africa afer swynnertoni

pealopesi

Dias, 1951

E 25-70 x 11-29

29 x 15

(39.9 x 21 '8)

Tetraonidae Lagopus scoticus

Britain

lovati

Seligman and E 19-25 x smaller Sambon, 1907 12-16

Tetrao urogallus

Britain Canada

mansoni bonasae

Sambon, 1908 E 12-1 3 x 9 Clarke, 1935b E 18-20 x 6-7

neavei

(Balfour, 1906) E 15-20 x 5-8

numidae costaie smithi

Kerandel, 1913 E 14-18 x 5-8 Tendeiro, 1947 (Laveran and El4 x 8-25 x 5 Lucet, 1905)

centropi

Fantham, 1921 R 12-14x 9-10 7-13 x 5-9

Bonasa umbellus

Numididae Sudan Numida ptilorhynchus =N . meleagris Numida meleagris Sudan Numida meleagris P. Guinea Meleagridae France Gallopava meleagridis Culculiformes S . Africa Centropus superciliosus = C.burchelli

14-18 x 5-7

E 54-86 x 1334 (73.4 x 23.8) 9 (44.5 x 19.0) E host nucleus 3 length parasite, measurements Sambon, 1908 E 40-56 syn. of lovafi E 25-40 x syn. of lovati 10-12 E

E E E 43-44

R

syn. of neavei syn. of neavei nucleus elongate and flattened, often divided

Cuculidae U.S.A. coccyzus americanus

coccyzus

Coraciiformes Congo Coracidae Eurystomus gularis Coracias India benghalensis Coracias India benghalensis C . abyssinica P. Guinea

eurysfomi

Coatney and R 12-14 x 11-15x9-11 R 13-17~ West, 1938 10-12 (12x 10) 12-1 3

coraciaef

Kerandel, 1913 R 14-15 x 12-14 E 16-21 x 11 R

R

sp. inquir.

melloi

de Mello and Alfonse, 1935 Bhatia, 1938 R

R

sp. inquir.

leitaoig

Tendeiro, 1947 R 10-17x 7-14 1 4 1 7 x 9-12

R 15-21 x

P. Guinea

francae

Tendeiro, 1947 R 12-14x

10-1 1

Switzerland

ralli

34-37x6-8

11-14x7-11 11-14 20-22 x 6-7

E 21-25 x

Gruiformes Rallidae Rallus aquaticus

Galli-Vallerio, E 26 1930

0

z

*n v3

E26-37x7-11

Eurystomus afer = E. glaucurus

(15 x 12) ? 11-16~ 10-13 (13 x 12) 6 E 3541

(13x 11)

1417 Q

R 15-18 x

13-16 8 E 48-67 x 11-14 9 E 55-61 x 10-11 8 R 15-18x syn.of 11-1 5 eurystomi R 15-21 x homoym of 11-18 8 francai E 3745 x Nikitin and 11-12 3 Artemenko, E 3049x 1927 8-9 6 E sp. inquir.

0

* n v l 0 -J

b

h C

c, 0

c, T

2N

0 0

z

-

TABLE I (continued) Order, family, species of host

Country

Species parasite

Author

h,

?

Shape and size female male

Host cell

Remarks

-

Charadriiformes C haradriidae Sarciopharus tectus

P. Guinea

Scolopacidae Scolopax rusticola

Portugal

Tendeiro, 1947 E 14-21

x

9-12 24-26 x 7-9

E 3-3

x

13-14 3143 x 9-11

Columbiformes S.E. Asia Columbidae Stretopelia tranquebarica = Turtur hrimilis S . turtur Spain

Musophagiformes Musophagidae Crinijier piscator = C . africanus Strigiformes Strigidae Athene noctua A . noctua

sou-sadiusih

Iegeri

Franca, 1912a R 12 x 9

marchouxi

Mathis and R 11 Lkger, 1910c

turtur

CovaledaR Ortega and Gallego Berenquer, 1946 Tendeiro, 1947 R 10-13 x 8-11 11-12x 8-9

P. Guinea

dnizi

Europe

danilewskyi

smaller

9 d

R

nucleus around cap-Ii ke

R

IS:59

R

syn. of marchouxi

++

R 11-16x 10-13 12-14x

(Ziemann,

E 1 1-21 x 4

smaller

nucleus

9 ca. + around

10-11 d E 40-55 x 5-8

1898)

Europe

Glaucidium Brazil brasilianum = G . brasiliensis

ziemanni lutzi

(Laveran,

E 12-21 x 4-7 1903) Carini, 1920 E 15-17 x 12-14 x 7-9 10-1 2

R E 40-55 x 5-8 E 3245

syn. of danilewskyi syn. of danilewskyi

g

Caprimulgiformes Caprimulgidae Caprimulgusfossei = Scotornis fossii Passeriformes Corvidae Corvus corm Pica pica

Congo

caprimulgi

Kerandel, 1913 E 16-18 x 6-9 R 12-16x7-11

Britain

sakharofi

Sambon, 1908 R 12

Britain

berestnefi

GarruIus glandarius Portugal

E 38-40

syn. of danile wskyi ?

12

R 14

Sambon, 1908 R 14x 10

11 x 7

R

Iaverani

Franw, 1912a R 8-1 1 x 6-9

smaller

R

11 x 10

R

host nucleus +-$ around measurements Wingstrand, 1947 host nucleus oval, flattened 2 host nucleus m 3 around CA syn. of

same

R

R 13 x 12

Corvus corone

Corsica

zuccarellii

LRger, 1913

Timalidae Liothrix Iuteus

China

liothricis

(Laveran and R 7-8 Murullaz, 1914) R 11 Mathisand Lkger, 1910a

2

sakharofi

Pycnonotidae S.E. Asia Ixus hainanus = Pycnonotus sinensis Pycnonotus c. cafer India = Molpastes c. cajer Irenidae India Chloropsis aurifrons frontalis = C . a. davidsoni C . cochinensis India jerdoni Paridae Europe Parus major

brimonti

b

m

4 R 13

T

2N

molpastis

dehlello, 1937a R

R

sp. inquir.

chloropsidis

de Mello, 1935 R

R

sp. inquir.

enriquesi

deMello, 1937a R

R

sp. inquir.

majoris

(Laveran, 1902)

R

host nucleus ++around

R 11-12

%

0 0

2

w

L

P

TABLE I (continued) Order, family, species of host

Country

Species parasite

Author

Turdidae Turdus musicus T. merula = Merula merula P.pilaris

S.E. Asia

dubreuili

Portugal

mirandae

?

franqai

T. iliacus

Africa

giovannolai

Fringillidae Fringilla coelebs Carduelis chloris =Passer chloris

Europe

fringillinarum Woodcock, R 11 x 7 1910 seabrae Franqa, 1912a R

Portugal

Corsica Petronia petronia = Fringilla petronia Meliphagidae Australia Anthochaera chrysoptera = Annellobia chrysoptera Ploceidae Niger Sitagra melanocephala = Hyphantornis melanocephala

?

Shape and size female male R

Mathis and R 10 x 8 Leger, 1911a Franqa, 1 9 1 2 ~ R

R R

Nikitin and R Artemenko, 1927 Dias, 1954 R

gentili

LCger, 1913

anellobiae

(Cleland and Johnston, 1911)

bouffardi

Leger and R 10 Blanchard, 1911

Host cell

R smaller

R R

R 14-15 x 10-12 12-14 R

10

x

7-8

Remarks host nucleus almost circles syn. of dubreuili sp. inquir. probably dubreuili sp. inquir. probably dubreuili like marchouxi sp. inquir. probable syn. of dubreuili

R

13:15?

R

host nucleus $ around

R 18-20

E

Passer griseus Ektrilididae Lonchura pmctulata topela = Munia topela Emberizidae Emberiza cirlus Hirundinidae Hirundo spp.

(=ongo S.E. Asia

monardi roubaudi

Portugal

carnbournaci Franw, 1912b R 11-17 x 8 (11) hirundinis Hsu el al., R (1973)

Europe

Rodhain, 1931 R 11-12 Mathis and R 11 Lkger, 1911a

R =round. E=elongate. c Species inquirenda. Synonym. Emended by Bray (1964) from costue. f Emended by Bhatia (1938) from L. coruciue benghulemis. Emended by Bray (1964) from L . ZeitGoi. Emended by Bray (1964) from L. sousu-dhsi. a

10 smaller

R 14 R

R R

host nucleus

3 around

sp. inquir. subspecies of Sergent and Sergent (1905)

0

2

16

A . M U R R A Y FALLIS, S H E R W I N

s.

DESSER A N D RASUL A . K H A N

size and an oval rather than elongate nucleus. Comparison of illustrations reveals a remarkable similarity and it is doubtful if the two species caa be separated by these criteria. We believe that the names L. ardeolae and L. iowense are junior synonyms of L. ardeae. L. Ieboeuji may be the valid species in the order although M. LCger, who identified L. ardeae, collaborated with Mathis in the description of L. leboeu- and must have been convinced of differences. In our view the last two species should be retained at present.

C. ANSERIFORMES

Herman (1938b) considered L. anatis Wickware (1915) a synonym of L. simondi (Mathis and LCger, 1910~).It appears to have a cosmopolitan distribution (Lapage, 196l)although most records are fromthenorthern hemisphere. The validity of L. anseris Knuth and Magdeburg (1922) from domestic geese is less certain. We share the opinion of Herman (1968) and Hsu et aZ. (1973) that this name is also a synonym ofL. simondi. Certainly L . simondiis reported from wild geese (Laird and Bennett, 1970) and has been transmitted experimentally to domestic geese (Fallis et al., 1956). The reverse transfer does not appear to have been attempted although Stephan (1922) noted that gametocytes from geese survived when inoculated into a duck. The size and round appearance of L. anseris in the original description (Knuth and Magdeburg, 1922) suggest it is distinct although in a second paper (1924) they refer to parasites in elongate cells and these were noted also by Stephan (1922). Fluorescent antibody studies by Barrow and Miller (1 964) support the concept of a single species. Observations by Desser and Ryckman (unpublished) indicate that the strain of L. simondi from ducks which they are studying behaves differently in geese as elongate gametocytes were not seen for 4 weeks following infection. This might suggest that the parasite in geese is a distinct species if it were not known to have come from a duck. Occurrence of round and elongate gametocytes in infections with L. simondi in ducks has led to confusion and the belief that the infections were mixed (Huff, 1968). This was disproven by the experimental studies by Yang et al. (1971) who inoculated ducks with merozoites from megaloschizonts and found elongate and, later, round gametocytes in the peripheral blood. This sequence would be expected from our knowledge of the life cycle (Fallis et al., 1956; Desser, 1967) and the assumption that some merozoites from megaloschizonts become hepatic schizonts. Two types of gametocytes are known for other species also, e.g. L. daniZeien.skyi (Fallis and Bennett, unpublished; Khan, unpublished) and L. bonasae (Newman, 1968, 1970), although a clear association of round gametocytes with merozoites from hepatic schizonts has not been established. Available evidence indicates that L. simondi is the only species in the Anseriformes. Has this restriction arisen because of the specialized feeding behaviour of the vectors which seem to select these species of birds? The reverse appears to prevail for L.fringilharum which occurs in several kinds of birds and which can be transmitted in a single locality by several species of simuliids.

O N SPECIES O F L E U C O C Y T O Z O O N

D.

17

FALCONIFORMES

Species of Leucocytozoon have been described from several hawks but experimental work is lacking. L. laverani Franchini from Albanella pallida is a homonym of the species described under this name by Franca (1912a). Franca (1927) redesignated this parasite L. franchini. Measurements for L. mathisi were not given in the description and those for L. circaeti have been calculated from the illustrations only. The validity of these species is uncertain. They are retained pending data on schizogony and specificity although we suspect they and L. martyi are synonyms of L. toddi or L . nudieri. The large gametocytes L. beaurepairei distinguish it from the others. E. GALLIFORMES

The status of several species from birds in this order remains debatable in spite of the attention some have received. Sambon illustrated (1908) and named L. macleani from specimens seen in Phasianus colchicus. He gave neither measurements nor description ; consequently it is listed as species inquirenda. Surprisingly, this is the only record from the common pheasant. Pheasants and quail exposed during the summer adjacent to ruffed grouse, ducks and other birds carrying species of Leucocytozoon did not become infected (Fallis et al., 1956). More recently Roslien and Haugen (1970) found none in 364 pheasants (Phasianus colchicus), nor in 763 Bobwhite quail (Colinus Virginia) examined from April to September in the U.S.A. Possibly the parasite occurs in pheasants in Europe but not in North America. Prowazek (1912) in describing L. schiifneri from Gallus gallus said it was larger and less granular than L . sabrazesi from the same host. These characters are rather inconstant and we share the opinion of Levine (1973) that the name L. schiifneri is most likely a synonym. Three species with round gametocytes, namely L . schoutedeni, L. andrewsi and L . caulleryi, are distinct from those referred to above. L. galli is species inquirenda. L. galli is known only from Europe, L. schoutedeni from Africa, L. andrewsi from U.S.A., and L . caulleryi from Asia and Africa (Rousselot, 1953; Fallis er al., 1973). Possibly L. andrewsi occurs naturally in a wild bird and is not normally transmitted to poultry as it has been reported only once ofL. caulleryi. L . schoutedeni (Atchley, 1951).We do not believe it is a synony%m was noted in 17 % of the chickens Rodhain et al. (1 9 13) examined in the Cqngo, and Jacobson (Fallis et al., 1973) found it in more than 50% of a sample of chickens examined in East Africa. Leucocytozoon caulleryi which was placed in a separate genus (Bennett et al., 1965)differs, as stated previously, from other species with round gametocytes as the nucleus of the infected cell disappears. L. kerandeli and L.francolini are similar to L. neavei and L. sabrazesi. Round rather than elongate cells were noted in some birds infected with L. kerandeli. In view of the occurrence of gametocytes of other species in round and elongate cells at different times in their life cycles, the round forms described as L. mesnili may be L. kerandeli. L . kerandeli and L.,francolinimay be the same as L. neavei. L . pealopesi is larger than the other species. Borg (1 949) was convinced from his extensive study on capercaillie, black

18

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

grouse, and hazel grouse in Scandinavia that L. lovati is the valid species, and we incline to his view. It must be noted, however, that L. mansoni is smaller and that Sambon was involved in the description of both species (Seligman and Sambon, 1907; Sambon, 1908). Resemblance to L. neavei is also obvious. Until the life cycles in the different birds are known it is advisable to retain the three species although it would be almost impossible to assign a name to a specimen without knowing the bird from which it was taken. L. sabrazeji from chickens resembles the parasites in grouse but chickens did not become infected when exposed for several weeks in a locality with infected grouse (Fallis et al., 1956). Greiner (1972) also noted the absence ofLeucocytozoon sp. in pheasants and quail captured in a locality where the grouse were infected. L. sabrazesi appears restricted to south-east Asia. Probably L. numidae and L. costaiare the same as L. neaveialthough L. costai appears to be somewhat larger. Balfour (1908) noted the similarity of the parasite in francolin to L. neavei although cross transmission was not attempted. In two different years (unpublished data) we exposed six guinea fowl for several weeks at ground level or in the forest canopy in Algonquin Park, Canada, in the vicinity of ruffed grouse and passeriform birds infected with Leucocytozoon spp. None of the guinea fowl became infected but it is not known whether flies fed on them. Franchini (1924) believed L. lovati, L. sabrazesi and L. neavei are similar. Leucocytozoon smitlzi of turkeys was among the first species to be observed. Smith (1895) illustrated but did not describe the parasite which is known from North America and Europe. The gametocytes are characteristically oval although round forms are seen also. The nucleus of the host cell is flattened, often divided on two sides of the parasite, and extends along $4its length. The appearance and life cycle distinguish it from other species. F.

CUCULIFORMES AND CORACIIFORMES

L. centropiand L. coccyzus are rather similar in size but are considered distinct as they were described from birds in different families. The former was not illustrated. Hsu et al. (1973) believe, and we agree, that the parasite described as L. franpae by Tendeiro is L. eurystomi. The name is a homonym, however, as Nikitin and Artemenko described a parasite from the thrush under the name L. francai. Hsu et al. are of the opinion that L. leitaoi and L. coraciae are the same but measurements of the latter were not given and the description is inadequate. Neither measurements nor illustrations ofL. melloi were given and we designate it species inquirenda. G.

GRUIFORMES AND CHARADRIIFORMES

L. legeri is presumably a valid species but L. ralli is species inquirenda as the description is brief and no illustration was given. L. sou-sadiasi is accepted although the possibility of its being a species from a bird in another order cannot be dismissed.

O N SPECIES O F LEUCOCYTOZOON

H.

19

COLUMBIFORMES A N D MUSOPHAGIFORMES

The identity of L. marchouxi and L. turtur is uncertain. We share the opinion of Levine (1954) and Hsu et al. (1973) that the latter is ajunior synonym. LCger (1913) identified the parasite as L. marchouxi from the same species of bird. L. dinizi is the only species described from birds in the second order. I.

STRIGIFORMES A N D CAPRIMULGIFORMES

Similarities in the size and appearance of L. danilewskyi, L. ziemanni and L. lutzi lead us to believe a single species occurs in this order. Carini (1920) suggeststhat it is difficultto distinguish L. lutzifrom L. ziemanniand comparison of the illustrations of L. ziemanni and L. danilewskyi indicate (Figs 31, 33) their similarity. The round gametocytes in early patency are in round cells. Later, round and oval gametocytes are seen in elongate cells (Fig. 32). In all types the nucleus of the host cell is pushed to the side and extends around most of the circumference of the gametocyte. Oval gametocytes are more numerous in blood films from some owls and the round forms predominate in others. This was especially noticeable in blood films from Athene noctua and Otus scops which one of us (A.M.F.) was privileged to examine in Professor Corradetti’s Laboratory in Rome. The significance of these different gametocytes may become apparent when the schizogonic cycles are understood. Observations by Khan (unpublished) reveal hepatic and renal schizonts. Some of the latter resemble megaloschizonts but it is unknown whether they develop from syncytia and are comparable to the megaloschizonts of caulleryi, sakharofi and simondi. It remains to be seen whether the shape of the gametocyte and the cell harbouring it are related tG the different types of schizonts. Kerandel (1913) described L. caprimulgi and noted the similarity to L. danilewskyi. A comparison of illustrations of the two species supports this opinion although the species might be retained until other stages in the life cycle are known. J.

PASSERIFORMES

More than 25 % of the described species occur in this order. All have round or oval gametocytes in round cells. Gametocytes of species in the corvids are of rather similar size and appearance (LCger, 1913; Coatney and Roudabush, 1937; Coatney and West, 1938; Fallis, 1950; Ramisz, 1962; Khan and Fallis, 1970b). Sambon,in his description of L. sakharofi from the raven (1908), stated that the nucleus of the host cell almost surrounded the parasite whereas the nucleus of L. berestnefi from magpies was flattened and pushed to one side. LCger (1913) described L. zuccarellii from Corvus corone but remarked in a later paper (1917) that it resembled L. sakharofi. Coatney and West (1938), Wingstrand (1947) and Hsu et al. (1973) consider it a synonym of sakharofi. FranCa (1912a) noted the similarity of laverani to sakharofl but evidence to indicate synonymy is not available. Ramisz (1962) measured specimens from the corvids from which the four species were described and concluded all were valid. Fallis (1950) was of the opinion that L. berestnefi and L. sakharofi are synonymous but recent observations of schizogony in crows and magpies (Clark, 1965; Khan and Fallis, 1970b) compared with those of Wingstrand

20

A . MURRAY FALLIS, S H E R W I N S . DESSER A N D RASUL A . K H A N

(1947, 1948) on L. sakharoj’i, convince us that these two species are valid. The megaloschizonts reported by Wingstrand for sakharofi were not observed by Clark in magpies nor by Khan and Fallis (1970b) in the blue jays, crows, and ravens with which they worked. They remarked that the concurrent appearance of renal and hepatic schizonts in the blue jay 5.5 days after it received sporozoites suggested a schizogonic cycle resembling that of L. fringillinarum although schizonts of the latter are not reported from the spleen (Khan and Fallis, 1970a). Possibly Khan and Fallis were working with L. laverani. More data on life histories and experimental cross infections should clarify these taxonomic problems. Status of the species L. liothricis, brimonti, molpastis, chloropsidis and enriquesi is questionable. The last two are rather similar in appearance although descriptions are inadequate for identification. L. brimonti resembles L. mesnili which LCger and Mathis (1909) considered similar to L. majoris. Fallis and Bennett (1962) believed the species of Leucocytozoon in Turdus migratorius was L. mirandue. This was based on the tendency to a broadly oval shape of the parasite, its size, and the appearance of the nucleus of the host cell which conformed to Franca’s description (1912c), namely “il est tantat rCduit a une band tr6s Ctroite dans toute son extension, tant6t amincie vers le milieu et Cpaissie vers les extrimities”. Later Khan and Fallis (1970a) decided L. mirandae should be considered a synonym of L. dubreuili although the latter is often round rather than oval and the nucleus of the host cell often surrounds more than 3 of the circumference of the parasite and lacks the “knob-like’’ ends. Experimental studies (unpublished) on a species identified as L. dubreuili from Turduspilaris in Norway suggested that it could be transmitted to a small cage bird called the zebra finch, Taemopyga castonotis Gould. Possibly L. dubreuili is less specific than was supposed hitherto. Insufficient information on L. giovannolai and L.francai is available to decide their status with certainty although they appear similar to L. dubreuili. L. fringillinarum has been transmitted experimentally to different birds (Fallis, 1965; Fallis and Bennett, 1966) and natural infections have been noted in species in the families Fringillidae, Icteridae, Parulidae, and Pocidae (Fallis and Bennett, 1962).Probablyit occurs in othersalso. Wetmore(l94l)considered that the species in doves and grackles were similar. The wide distribution and lack of specificity of L. fringillinarum leads to the belief that several of the species described from passeriformes may be synonymous. L. seabrae is species inquirenda. Gametocytes of L. gentili are larger than those ofL.fringillinarum. Cleland and Johnston (1911) described an oval parasite in the blood of Anthochaera chrysoptera (syn. Anellobia chrysoptera) from New South Wales, Australia as Trypanosoma anellobiae emending it later (Cleland, 1915 ) to the genus Leucocytozoon. The parasite adhered closely to the nucleus of the parasitized cell. Many parasites, probably macrogametocytes, were deeply stained ; paler forms, probably microgametocytes, were also observed. They were seen in several species of birds and Breinl (1913) and Cleland (1915) reported other hosts. Mackerras and Mackerras (1960) provided a fuller description of L. aneflobiae. The nucleus of the host cell appeared as a cap- or band-like structure on the parasite and extended up to half way around it.

ON SPECIES OF LEUCOCYTOZOON

21

In this respect it resemblesL.JringiZZinarutn.The species reported from the families Ploceidae, Estrilidae and Emberizidae are somewhat similar and rather like L. majoris.More data are required to establish their specificidentity withcertainty. Sub-species have received no consideration in this report although recently Hsu et aZ. (1973) raised hirundinis to the status of a species. Sergent and Sergent (1905) had designated this parasite from swallows as a sub-species of L. danfZewskyi.Hsu and co-workers believe it should be a species because of lack of evidence of transmission of a species from a bird in one order to one in a different order. This would be more convincing if based on the results of cross transfers and especially since the description of the species is rather inadequate. It would be preferable to designate it species inquirenda. IV. LIFECYCLES A.

SCHIZOGONY

Life cycles of a few species of Leucocytozoon are known, albeit rather incompletely, from scattered observations on naturally infected birds and on limited numbers infected experimentally. None of the latter was initiated with vectors reared in the laboratory* although this is necessary to ensure that the flies have not been infected previously. Nevertheless, work with flies of unknown prior history has been subjected to some controls and indicates general patterns of cycles investigated thus far. Early investigators described and illustrated structures believed to be developing schizonts (Fantham, 1910a; Moldovan, 1913; Mine, 1914; FranCa, 1915; Knuth and Magdeburg, 1924; Giovannola, 1936; Ivanic, 1937; Clarke, 1938). The work of Huff (1942) and Wingstrand (1 947, 1948) on L. sfmondi and L. sakharofi, respectively, stimulated research which has led to our present understanding. The data suggest that two types of schizogonic cycle exist, one exemplified by L. simondi, the other by L. dubreuizi. Comparisons can begin conveniently with the sporozoite, the stage common to all. Small differences in size and appearance of sporozoites of different species have been noted but no detailed comparisons are reported. Sporozoites ofL. sitnondftransmitted to a duck by a simuliid initiate schizogony in parenchymal cells of the liver (O’Roke, 1934; Huff, 1942; Fallis el al., 1951; Desser, 1967). The stimuli which direct these “brainless” organisms to enter these cells are unknown. Possibly they enter various cells at random but survive only in those of the liver. Clearly some sporozoites do not develop immediately as those of at least 2 species have been seen in different organs several days after their transmission (Khan et al., 1969). Hepatic schizonts mature and discharge their contents 4-6 days after a duck has received sporozoites (Fig. 43). Schizonts which appear mature measured up to 45 pm (Eide and Fallis, 1972). Merozoites and syncytia are released from hepatic schizonts (a syncytium as used herein refers to cytoplasm bounded by a plasma membrane and containing two or more nuclei). Merozoites enter erythrocytes and erythroblasts and grow into gametocytes. Others probably enter parenchymal cells of

* I. B. Tarshis reported recently in a paper read August 25, 1973 to the Wildlife Disease Association that the sporogoniccycle of L. simondi had been followed in laboratory-reared Cnephh ornithophiliu and that the flies fed a second time and transmitted the sporozoites.

22

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

* FIG. 43. Maturing hepatic schizont (section) x 1200. FIG. 44. Mature megaloschizont (section of spleen) x 400. FIG.45. Round macrogametocyte (blood film) x 1400. FIG.46. Maturing microgametocyte. Note “spireme-like’’appearance of chromatin (arrow) (blood film) x 1200. * Figs 43-68

are L . simondi unless otherwise indicated.

23

O N SPECIES OF L E U C O C Y T O O Z O N

the liver to initiate a second schizogonic cycle, although evidence is scanty. The syncytia are presumably phagocytized by macrophages or other RES cells throughout the body and grow into megaloschizonts (Fig. 44) described by Huff (1942), Fallis et al. (1951), Cowan (1955), Desser (1967). The term, although descriptive, is somewhat misleading as it includes the enlarged host cell and its hypertrophied nucleus, the “central body” of some authors, as well as the large schizont within. We favour retention of the term and assign the following criteria to distinguish megaloschizonts from other types : (i) they originate from hepatic schizonts and develop in reticulo-endothelial cells, particularly vascular endothelium ; (ii) they cause extreme hypertrophy of the nucleus of the host cell; (iii) they may be from 100 pm to more than 400 pm in diameter. Megaloschizonts of L. simondi may be found in the vascular endothelium of any organ. They are especially abundant in the spleen and lymph nodes. Their scarcity in the liver, where they originate, is unexplained. Megaloschizonts require about 4 days to mature or more in some sites, e.g. the brain. They measure at maturity up to 200 pm in diameter and produce one million or more merozoites. These, when released, enter lymphocytes and other leucocytes which become attenuated. The elongated, distorted nucleus of such cells lies to one side of the oval gametocyte. Some merozoites from megaloschizonts, as indicated by studies of Yang et al. (1971), presumably initiate another generation of hepatic schizonts. A characteristic parasitaemia results from these two types of schizonts. Merozoites from hepatic schizonts develop into round gametocytes in erythrocytes and erythroblasts which are seen during early patency (Fig. 45). Gametocytes which are often oval rather than round and hereafter are referred to as elongate gametocytes, develop from merozoites of megaloschizonts and are not seen until the fifth day of patency or later. In birds with light infections the round forms may be scarce and overlooked and the appearance of elongate gametocytes may seem to indicate the beginning of patency. The maximum parasitaemia usually occurs 10-12 days following infection, after which it drops to a low, fluctuating, chronic level that may persist for years. Parasites are not always demonstrable in peripheral blood during this period. An increase of round and elongate gametocytes during chronicity indicates that cycles of schizogony are continuing. Ducks are known to retain infection for at least 2 years and we have robins which have retained L. dubreuili for 5 years. The present concept of this type of cycle is as follows :

sporozoites

-

\ 7

schizonts in hepatocytes ---+

___+

merozoitesksyncytia

round gametocytes

1

, , imegaloschizonts n RES cells

merozoites -----+ elongate gametocytes

24

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

L. simondi develops also in domestic and wild geese (Fallis et al., 1956; Desser and Ryckman, unpublished). Fallis (unpublished) and Herman (personal communication), noted round and elongate gametocytes, although domestic goslings often died before gametocytes appeared in attenuated cells. Different results were noted in research now in progress by Desser and Ryckman. In their experiments elongate gametocytes in attenuated cells were not detected in young Canada geese while under observation for several weeks. Moreover, few of these birds died compared to those observed by Herman et al. (1970). Is this indicative of different strains? Or is formation of megaloschizonts unnecessary in the cycle? Are megaloschizonts produced only if hepatic schizonts rupture prematurely, thus releasing portions, the syncytia, which have not formed into merozoites? Results of the research by Desser and Ryckman, and Herman and colleagues, will be awaited with interest. Wingstrand (1947,1948) found some of the megaloschizonts ofL. sakharoji measured 480 pm and the nucleus of the host cell 190 pm. He illustrated structures in macrophages which appear to correspond with the syncytia seen in L. simondi. Hepatic schizonts were not reported. This is understandable, as he was studying birds which were infected naturally at unknown times and the presence of many megaloschizonts suggests that the hepatic cycle was completed. The megaloschizonts of L. caulleryi and their location in several tissues are featuressimilar toL. simondi. Akiba( 1970) and Akibaetal. (197 1)noted schizonts in several organs on the seventh day after transmission of sporozoites, and merozoites 7 days later. Possibly these are second generation schizonts, as Kitaoka et al. (1972) in quantitative studies of schizogony remarked that “hundreds of schizonts were produced from a sporozoite”. Pan (1963) noted a structure in blood films from chickens infected with L. caulleryi, “that consists of several small nuclei in a blue-stained common cytoplasm”. These are similar to the syncytia seen following the rupture of hepatic schizonts of L. simondi and which we have seen occasionally in the blood of birds with a high parasitaemia and in imprints of the liver and other organs. Unfortunately Pan does not state the time these were seen relative to the time of infection. Their presence leads to the speculation that megaloschizonts of the two species have a similar origin. Recently megaloschizont-like bodies were reported from parakeets (Walker and Garnham, 1972; Borst and Zwart, 1972). An aberrant form of Leucocytozoon was suggested although gametocytes, the basis for identification of species of Leucocytozoon, were not seen. The significanceof megaloschizonts is far from understood as they are known for the above species only. Might they arise because of abnormalities of development of the parasite in a particular host rather than being characteristic of the speciesper se? Newman (1970) found large schizonts in renal cells of grouse infected with L. bonasae. The nuclei were hypertrophied. Some of the parasites were in epithelial cells and he thought others might be in phagocytic cells. He considered them homologous to megaloschizonts of L. simondi. Khan too (unpublished) has seen large schizonts which he thought were megaloschizonts in kidneys of owls infected with L. danilewskyi. They were present at the same

O N SPECIES OF

25

LEUCOCYTOZOON

time as hepatic schizonts, consequently they may have developed from sporozoites. We believe their cycles may be variants of the second type of schizogonic cycle which was revealed by experimental studies of L. dubreuili in robins and L. fringillinarum in grackles (Khan and Fallis, 1970a). The initial cycle of L. dubreuili and L. fringillinarum occurs in parenchymal cells of the liver. First generation schizonts of L. fringillinarum develop also in renal epithelial cells. Schizonts measured (pm) as follows:

liver kidney

L. dubreuili 1st generation 30 x 27 2nd generation 31 x 26 1st generation absent 2nd generation 45 x 29

L. fringillinarum 23-41 x 17-34 45 27x 18 74 x 32

The primary cycles are completed in 3-4 days, that for L. fringillinarum being slightly more rapid. The second generation of each species occurs in the liver and kidney, that of fringillinarum being larger than that of dubreuili. Nuclei of kidney tubule cells containing first and second generation schizonts of L. fringillinarum are enlarged as are those of liver cells containing first generation schizonts. Cycles of species in grouse (Clarke, 1938; Borg, 1949; Newman, 1968, 1970),in magpies (Clark, 1965),and turkeys (West and Starr, 1940; Richey and Ware, 1955; Newberne, 1955; Simpson et al., 1956; Wehr, 1962) have similarities to those of fringillinarum and dubreuili. Khan and Fallis (1970b), in preliminary studies of a species in corvids which they did not identify with certainty but may be L. laverani, observed schizonts in the liver, kidney and spleen of an experimentally infected blue jay, but only in the liver and kidney of a crow and raven. The nuclei of the parasitized renal cells were enlarged. These differences in schizogony from that known for L. sakharofi support the concept of more than one species in corvid birds. Newman (1968) illustrated schizonts of L. bonasae which he saw in the kidney and called megaloschizonts. These are larger than hepatic schizonts and resemble second generation schizonts of L. dubreuili and L.,fringillinarumrather than the megaloschizonts of caulleryi, sakharofi and simondi. The second type of cycle as exemplified by L. dubreuili in parenchymal cells can be summarized as follows : sporozoites

-

schizonts in ,ZIIZZ? hepatocytes

\

\7

merozoites

I

-

schizonts in renaI cells

round gametocytes

/

26

A. M U R R A Y FALLIS, SHERWIN

s.

DESSER A N D R A S U L A . K H A N

The shape and appearance of gametocytes and those of the cells containing them raise several questions. Species referred to above which occur in attenuated cells are also found in round cells, especially in early patency. It is our opinion that gametocytes of L. bonasae, danilewskyi, neavei and possibly smithi in round cells, are seen for a shorter time than those of L. simondi. The elongate parasites of L . simondi are associated with the merozoites of megaloschizonts but such schizonts are unknown for L. smithi and bonasae. Furthermore L. sakharofi has megaloschizonts but gametocytes are in round cells only. Yang et al. (1971) established that the round and elongate forms of L. simondi belong to the same species. They inoculated single megaloschizonts intravenously into young ducklings and observed elongate gametocytes 2-7 days later and round gametocytes at 6-1 1 days. This is the opposite of the sequence observed following inoculation of sporozoites. It is the sequence expected if merozoites from megaloschizonts develop into elongate gametocytes and others initiate hepatic schizogony which in turn produces merozoites that develop into round gametocytes. The relationship of the two types of gametocytes to the respective schizonts of other species is not understood. L. danilewskyi, for example, has round gametocytes in round cells at the beginning of patency. Later round and oval forms are seen in attenuated cells. The proportion of round vs elongate gametocytes in attenuated cells is variable in films from different birds. Perhaps it is related to the kind of schizont producing the merozoite, for Desser and Ryckman (unpublished) found neither elongate gametocytes nor megaloschizonts in wild geese infected with L. simondi which were examined for a month. Round gametocytes may be more important in the initiation of sporogony than elongate forms. Roller and Desser (1973b) found in in vitro studies of exflagellation of L . simondi that only round gametocytes escaped from their host cells, matured and exflagellated. This confirmed similar observations of Martin (1932). Rawley (1953), however, reported exflagellation of elongate gametocytes and we have seen this occasionally. Prepatent periods of 5-6 days have been noted (Fallis et al., 1956; Desser, 1967) in birds infected with L. simondi and 4-5 days (Khan and Fallis, 1970a in birds infected withL..fringillinarurnand L . dubreuili.Baker (1970) saw developing gametocytes in rooks 8 days after they received sporozoites of L . sakharofi. Skidmore (1932) saw fully grown gametocytes in the blood of turkeys 12 days after they received sporozoites of L. smith. Noblet et al. (1972) report a prepatent period of 13-14 days for the same species. The prepatent period in guinea fowl and chickens infected with L. neavei and L . schoutedeni respectively was 14 days or less (Fallis et al., 1973). The variability reported in the literature is possibly related partially to the intensity of the infections, as parasites may be overlooked if they are scarce. This would explain the failure to find round gametocytes at the beginning of patency of species known to have both types. The parasitaemia was followed in infections with L. simondi (Fallis et al., 1951;Chernin, 1952a; Roller and Desser, 1973a),althoughquantitativemeasurements are difficult to obtain. Maximum parasitaemia was noted 9-12 days postinfection. A slow decline to a chronic level followed and no parasites were detected at times. Their disappearance and later reappearance was noted

O N SPECIES O F

LECJCOCYTOZOON

27

especially in chickens infected with L. caulleryi (Mathis and Lkger, 1909b). Roller and Desser (1 973a) described a diurnal periodicity in the parasitaemia of ducklings infected naturally and experimentally with L. simondi. Peak parasitaemia was noted during daylight hours and coincided with the prominent feeding period of a vector (Bennett, 1960). Various authors note that microgametocytes are often less numerous than macrogametocytes. We have noted in blood films made at different times from the same bird that the ratio of male to female gametocytes may vary from 1 : 1 to 1 : 5. The causes of the differences are unknown. B.

SPOROCONY

Known sexual cycles occur in species of Simuliidae except that of L. caulleryi which develops in species of Culicoides. Investigations thus far indicate considerable lack of specificity (Table 11). The widespread distribution of some species of parasites compared to the more limited distribution of species of flies also TABLE I1 Simuliid and cerafopogonid hosts for species of Leucocytozoon L. bonasae L. caulleryi L. danilewskyi L. dubreuili

L. fringillinarum L. neavei L. sakharofi L. schoutedeni L. simondi

L. smithi

Leucocytozoon sp. (corvids)

S. aureum, S. latipes, S. quebecense, S.croxtoni Culicoides arakawae, C. odibilis, C. circurnscriptus S. aureum S. latipes, S. quebecense, S. aureum, Cnephia ornithophilia, Prosimulium decemartieularum as for dubreuili S. adersi, S. nyasalandicum S. angustitarse S. adersi, “S. impukane”, S. vorax, S. nyasalandicum Ontario, Canada, S. anatinurn, S. rugglesi Michigan, U.S.A., S. rugglesi Cnephia ornithophilia, S. innocens Wisconsin, U.S.A., S. rugglesi Norway, Simulium s p . like doglieli S. parnassum S. occidentale (= S. meridionale) S. nigroparvum (= S. jenningsi) S. slossonae S. eongareenarum S. aureum, Prosimulium decemarticulatum

Fallis and Bennett, 1962 Akiba, 1960a Morii and Kitaoka, 1968a Fallis, Bennett and Khan, unpublished Khan and Fallis, 1970a Khan and Fallis, 1970a Fallis et al., 1973 Baker, 1970 Fallis et a/., 1973 Fallis et a/., 1956; Fallis and Bennett, 1966 Barrow et at., 1968 Tarshis, 1972 Anderson et al., 1962 Eide and Fallis, 1972 Levine, 1973 Skidmore, 1931 Johnson eta[., 1938 Wehr, 1962;Noblet et al., 1972 Noblet et al., 1972 Khan and Fallis, 1970b

28

A. MURRAY FALLIS, SHERWIN

s.

DESSER A N D R A S U L A . K H A N

suggests lack of specificity for the vector. Sporogony may of course occur in flies that are not necessarily vectors. S. venustum, which feeds on mammals, is a suitable host for L. sirnondi and perhaps others (O’Roke, 1934; Fallis et al., 1951;FallisandBennett, 1962; Desser and Yang, 1973). Likewise L. schoutedeni will develop in the mammalophilic flies S. vorax and S. nyasalandicurn (Fallis et al., 1973). The pattern of sporogony appears similar in species studied thus far. A brief report by Martin (1932) described the beginning of sporogony of L. sirnondi. He noted the rapidity with which macrogametogenesis and exflagellation was completed, that gametocytes in attenuated cells did not take part in the process, and that the specialized anterior end of the ookinete was capable of lateral and forward movement. Our observations on L. sirnondi,dubreuili,fringillinarurn and danilewskyi indicate exflagellation of microgametocytes can begin 1-3 minutes after ingestion by a simuliid although some specimens may commence several mirwtes later. Roller and Desser (1973b) studied the process in vitro. A small opening appeared in the membrane investing the gametocytes and most of the cytoplasm as well as the nucleus of the gametocyte were extruded through the opening. A small, Feulgen-positive residual body remained within the membrane. Exflagellation of the microgametocytes followed. Prior to the formation of microgametes, eight of which were produced in those that could be counted, the chromatin is arranged first as a spireme (Fig. 46) then as a solid mass (Fig. 47) followed by separation into separate units one of which becomes incorporated into each microgamete as it forms (Fig. 48). Roller and Desser (1973b) demonstrated an inverse relationship between temperature and the time required for the commencement of exflagellation in vitro of gametocytes of L. simondi. Between 26” and 40”C, exflagellation usually occurred in 1-l+ min. Exflagellation occurred at 40°C, which approximates to the body temperature of the avian host. Thus a drop in temperatureper se is not necessary to initiate the process. Exposure of gametocytes to air, i.e. increased 0 2 and C02, stimulated exflagellation in vitro and probably does so also in the fly. The spherical zygote transforms into the elongate ookinete in 6-12 h at 20°C. It has a more or less central nucleus and several large crystalloid bodies (Trefiak and Desser, 1973) (Fig. 51). Flexing and forward motility is produced presumably by “waves” which move longitudinally along the body (Desser, unpublished). Penetration of the midgut of the fly was not observed although sections of flies revealed ookinetes in the process of doing so. Transformation of the ookinete to the oocyst occurs between cells or below the basement membrane of the midgut of the fly. This may occur in less than 48 h; other ookinetes remain in the midgut for several days. Probably their escape is delayed by the peritrophic membrane which develops around the ingested blood. After the ookinete is in position in the wall of the midgut of the fly a thin, transparent capsule forms around it as it changes to the oocyst. The early oocyst has a central core of crystalloid which appears as a vacuole in living and in alcohol-fixed specimens CFig. 49). The chromatin within the cytoplasm divides and when completed it becomes arranged peripherally in the oocyst. Small projections on the periphery of the oocyst indicate the beginning of

FIG.47. Advanced stage of maturation of a microgametocyte with compact chromatin and emerging flagella (blood film) x 1200. FIG.48. Exflagellation of microgametocyte with 8 forming microgametes (blood film) x 1200. FIG.49. Immature oocyst of L. dubreuili. Note crystalloid core (*) (saline preparation) x 1500. FIG.50. Maturing oocyst of L. dubreuili with sporozoites attached to residual body (saline preparation) x 1500. FIG.51. Ookinete with 2 large crystalloid inclusions (arrows) (smear of midgut) x 1200. FIG. 52. In vitro megaloschizont. Note hypertrophied hostcell nucleus (arrow) and syncytia in the cytoplasm x 480.

30

A. MURRAY FALLIS, S H E R W I N

s.

DESSER A N D R A S U L A. K H A N

sporozoite formation. These projections elongate at the expense of the cytoplasm to form the sporozoites (Fig. 50) each of which incorporates a portion of the crystalloid. The sporozoites with blunt ends pointing peripherally become detached from a residuum of cytoplasm and begin to move although still enclosed by the wall of the oocyst. Sporozoites escape gradually through the wall rather than simultaneously by rupture of it and make their way to, and penetrate, the salivary glands. Detailed comparisons of stages of sporogony of different species are not available. Effects on sporogony of the diet of the fly, temperature, peritrophic membrane and other factors await investigation. The size and shape of ookinetes of the same species are variable and specific separation would be difficult. Patterns of oocyst development of different species are similar but the size of the oocysts and the number of sporozoites differ. Oocysts of L. simondi, schoutedeni, neavei and fringillinarum are about 10-14 pm in diameter. Those of L. bonasae, dubreuili and danilewskyi may be more than twice this diameter and produce a correspondingly larger number of sporozoites. Sporozoites arise from a single germinal centre rather than several as in species of Plasmodium and in Haemoproteus columbae (Garnham, 1966). Sporozoites of some species are longer and narrower than others but specific identification is impossible at present. Rate of sporogony may differ within a species as well as among species. It may vary from 6 to 18 days in L. simondi (Fallis et al., 1956) in flies fed at the same time and kept under similar conditions at about 18-20°C. Strains of the same species developed in 7 days at 13-14°C in Norway (Eide and Fallis, 1972). This species is obviously adapted for development at low temperatures. Similar unpublished observations on L. dubreuiliin Norway likewise suggest adaptation to low temperatures. At 20°C sporogony of L. schoutedeni and L. neavei occurred in 6 or more days. Baker (1970) found sporozoites in the salivary glands of Simulium angustitarse 4-5 days after the flies fed on a rook infected with L. sakharoji. Comparison of sporogonic development at a series of temperatures is reported only for L. caulleryi. Morii and Kitaoka (1968b) found sporozoites in the salivary glands of Culicoidesarakawae in 6,4,3 and 2 days in flies kept at 15,20, 25, and 30°C respectively. Oocysts did not form at 12.5"C and sporozoites produced at 30°C were not infective at 3 and 5 days. Sporozoites were infective from 4-19 days in midges kept at 20°C and for 7-33 days in those held at 15°C. The same authors, according to Akiba (1970), reported zygotes and ookinetes in 30-60 min, oocysts in the intercellular midgut in 24 h and under the basement membrane in 48 h, and sporozoites in the body cavity and salivary glands in 72 h. Morii and Kitaoka (1968a, 1969) observed parasitaemia in chickens that received single sporozoites of L. caulleryi. Although not stated, it is assumed both macro- and microgametocytes were present. C.

CELLS INVADED

Opinions have differed on the kinds of cells occupied by gametocytes of species ofleucocytozoon.This is understandable as the host cell and its nucleus

O N S P E C I E S OF L E U C O C Y T O Z O O N

31

are altered early in the development of the gametocyte. The generic name can be misleading. It arose, as explained above, from the early view (Danilewsky, 1889) that the parasites were in leucocytes although later Danilewsky (1890) remarked on their occurrence in erythroblasts. Mathis and Ltger (1912) believed, on the basis of structure and staining, that elongate forms of L. kerandeli, sabrazesi and simondi were in erythroblasts. They believed that L. mesnili, caulleryi, marchouxi, brimonti, martini, leboeuji, roubaudi and dubreuili were in mononuclear cells. Levine (1954) reported L. marchouxi in lymphocytes. Sambon (1908) considered that the gametocytes of the species in grouse werein erythroblasts but Fantham (191Oa) believed those of L. Zovati were in mononuclear cells. Wenyon (1908b) and Keysselitz and Mayer (1909) held a similar view for the elongate L. neavei. Kuppusamy (1936) stated that the species in fowl was in erythrocytes. Kerandel(l913) too, stated that the round gametocytes were in mononuclear leucocytes and the elongate forms in erythroblasts. Laveran (1903), Cardamitis (191 l), and Franca (1912a) believed that L. ziemanni and the parasites in hawks and woodcock, respectively, were in erythrocytes. In contrast to these views Woodcock (1910) thought L. ziemanni occurred in leucocytes. Laveran and Lucet (1905) were of a similar opinion for L. smithi. Volkmar (1929) also thought it was in a modified reticulo-endothelial cell and that this might explain the apparent health of the birds as damage to the reticulo-endothelial system was repaired more easily than damage to the erythrocytes. Sakharoff (1893) believed the round parasites of the crow, raven, and magpie were in leucocytes and Berestneff (1904) agreed. Wingstrand (1948) thought young gametocytes of L. sakharoji were in lymphocytes and erythroblasts. He cautioned on the identification of cells in films and sections because of differences in sizes resulting from methods of preparation. It was LCger’s opinion (1917) that L. sakharoji was in mononuclear cells and lymphocytes and L. berestneji was in erythroblasts. Woodcock was convinced that L. fringilZinarum was in leucocytes (1910). Ltger (1913) stated that the parasites of Merula merula and L. gentili were in mononuclear cells. Franqa (1915) thought the former were in erythrocytes. Cleland and Johnston (191 1) reported immature specimens of L. annelobiae in “red cells”. Franqa (1912~)remarked that it is not the form of the host cell which determines the configuration of the parasite but rather the latter which affects the shape of the cell. If correct it follows that the appearance of the host cell could be a useful criterion in taxonomy. However, observations on L. danilewskyi indicate an exception as gametocytes which are distinctly round and others clearly elongate occur in similar, attenuated cells. Certainly our observations on L. simondi, L. bonasae, and L. danilewskyiindicate that elongation of a cell begins when the gametocyte within is small and increases as the parasite grows. Cook (1954) and Ramisz (1962) using the benzidine-peroxidazine reaction showed young parasites of L. simondi and L. sakharofi in erythrocytes. Studies by Desser et al. (1970a) on the fine structure of L. simondi indicate that elongation occurred only in leucocytes and that merozoites from hepatic schizonts develop into round gametocytes in erythrocytes and erythroblasts. Apparently merozoites of different species of Leucocytozoon occur in erythrocytes, erythroblasts and leucocytes

32

A . M U R R A Y FALLIS, S H E R W I N

s.

DESSER A N D R A S U L A . K H A N

but there is no pigment as suggested by some early observers. Granules ,in the extremities of some parasitized, elongate cells and their absence from others may indicate the type of leucocyte infected by the parasite. D.

RELAPSE

Moldovan (1913) remarked that parasites disappeared from the blood of an owl during the winter. Knuth and Magdeburg (1922, 1924) made similar observations on geese. Unpublished observations on ducks held over winter revealed scarcity or absence of gametocytes at times during the winter and a small increase in early spring (Fallis and Bennett, 1966). Huff (1942) and Chernin (1952~)studied the relapse in late spring. Desser et al. (1967) noted the parasitaemias from September to May in Pekin ducks which had been infected experimentally. An increase in round and elongate gametocytes occurred between March and May. The parasitaemias were followed also in black and mallard ducks during March. Young gametocytes were seen in'some of the birds. One such bird was killed and megaloschizonts were found in the lungs and heart. The megaloschizonts were smaller than many seen in primary infections. Landau and Chabaud (1968) noted that schizonts involved in relapses of Plasmodium spp. in rodents were smaller and grew more slowly than those in the initial cycle. Khan and Fallis (1970~)detected an elevated parasitaemia during March in saw-whet owls and two robins infected experimentally with L. danilewskyi and L. dubreuili respectively. Schizonts were found in the kidneys of the owls and robins. Bennett and Fallis (1960) noted an increase in parasitaemia in the non-migratory ruffed grouse in early spring as well as in robins and owls held over winter. These observations suggest, as did Chernin's ( 19 5 2 ~ and )~ Haberkorn's (1968) on Huemoproteus, that relapse is related more to the reproductive cycle than to stress such as might be associated with migration. Unpublished experimental work of Yang on L. simondi tends to support this view although the relapses he observed were minor compared to those known for certain species of Plasmodium. We have not seen hepatic schizonts of L. simondi during the autumn and winter. Their presence is indicated, however, by the round gametocytes which are more numerous during the spring. Clarke (1938) noted hepatic schizonts of L. bonusae during the winter. E.

TRANSMISSION

Intermediate hosts and their roles as vectors are known for few species (Table 1I) as difficulties of obtaining and maintaining a supply of parasite-free birds presents challenging problems apart from those on the organisms themselves. Present data indicate that simuliids are vectors of several species and L. caulleryi is transmitted by Culicoides spp. Possibly other species are transmitted by ceratopogonids, as Bray (1964) referred to a personal communication from Desowitz who found the parasite in francolin on the Jos plateau in Nigeria where Simulium spp. are absent. Species of Culicoides were suspected vectors. Garnham (1966) made a similar suggestion for a species of Leucocytozoon in Kenya in a locality without simuliids.

O N SPECIES OF

LEUCOCYTOZOON

33

Transmission, so far as known, occurs when birds are on their nesting grounds. This would seem advantageous to the parasite assuming, of course, that the vectors are prevalent when the birds are nesting. The situation may differ in tropical and subtropical countries if suitable vectors are present throughout the year and if birds nest at various times. Ecological and epizootiological studies among migratory and resident birds with different nesting habits could be informative. Akiba’s discovery of Culicoides arakawae as a vector of Leucocytozoon caulleryi opened a new chapter in the investigation of this parasite (1960a). Morii el al. (1965) and Morii and Kitaoka (1968b, 1969) showed that infective sporozoites developed also in C. circumscriptus,C . odibilis, and C. schultzei. C. odibilis fed avidly on chickens but had a minor role in transmission. C. schultzei normally feeds on cattle, consequently it is an unlikely vector. This lack of specificity for the insect leads us to expect that additional species of Culicoides will be suitable hosts. A similar lack of specificity is noted for species of Leucocytozoon which develop in and are transmitted by simuliids. Simulium rugglesi and S. anatinum are vectors of L. simondi in parts of northern United States and Canada (Fallis et al., 1956; Barrow et al., 1968). Simulium croxtoni and S. euryadminiculum were also named, but we now believe they were wrongly identified. Cnephia ornithophilia and Simulium innocens are also hosts in United States (Tarshis, 1972). A species of the Eusimulium group near S. doglieli is the vector of this species in Norway (Eide and Fallis, 1972). The parasite will also develop in Simulium venustum (see Desser and Yang, 1973) which feeds normally on mammals rather than on birds. L. fringillinarum also developed in this fly although the development appeared somewhat abnormal (Fallis and Bennett, 1962). L. schoutedeni of domestic chickens in Africa develops in S. adersi, in one of the S. impukane group and in S. vorax and S. nyasalandicum (see Fallis et al., 1973). The parasites develop as rapidly in the last two species as in the first two although the latter are abnormal hosts since they feed naturally on cattle. L. smithi develops in several simuliids. The feeding preferences of the flies may be more significant in transmission than the specificity of the parasite for the fly. The situation differs for L. fringillinarum and L. dubreuili as S. aureum, S. latipes, S. quebecense, Cnephiaornithophilia,and Prosimulium decemarticulatum feed on several kinds of birds and each is a suitable host for these two parasites and also for L . bonasae. Baker (1970) has shown that S. angustitarse is a host for L. sakharofl in England. Khan and Fallis (1970b) found that S. aureum and Prosimulium decemarticulatum are hosts for a species of Leucocytozoon in corvids in Canada. The parasites appear to have a more cosmopolitan distribution than the vectors. Consequently the list of vectors is likely to increase as more becomes known about transmission in different countries. In a recent personal communication, for example, Dr Tsu-Huai Fuh, Department of Veterinary Medicine, National University of Taiwan, says that his colleague Dr Chang infected a chicken experimentally with L. sabrazesi with sporozoites from S. (E.)geneculare.

34

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N F.

SPECIFICITY

Data on specificity are available for few species. L. fringillinarum has been transmitted experimentally to several kinds of birds (Fallis, 1965; Fallis and Bennett, 1966; Khan and Fallis, 1970a) and it shows little specificity for simuliids (Fallis and Bennett, 1962). These flies are known to feed on different birds and this too should favour maintenance and spread of this non-specific species. Since several of the hosts are migratory, transmission of this species could occur in some instances on the birds’ wintering grounds as well as in their nesting localities, but data are not available. L. simondi, in contrast to L.fringillinarurn, occurs predominantly in the Anseriformes (Fallis, 1965; Fallis and Bennett, 1966). Exceptions may be the single records from the black-bellied plover (Squatarola squatarola (L.)) and the short-billed dowitcher (Limnodromus griseus Gmelin) (Laird and Bennett, 1970). Skidmore (1932) found that only turkeys became infected with L. smithi although chickens, ducks and geese were in the vicinity. Mathis and Ltger (1910b) kept ducks, chickens, geese, turkeys and pigeons in a pen with chickens with L. caulleryi and L. sabrazesi. Only chickens became infected. Morii and Kitaoka reported (1 971) that Japanese quail, pheasant, bob-white, bamboo partridge and guinea fowl were resistant to infection with L. caulleryi. This is interesting as this species was reported recently from guinea fowl in Africa (Rousselot, 1953; Fallis et al., 1973). It is noteworthy also that Van den Berghe (1942) identified the round parasite 15 x 12.5 pm he found in Numida meleagris as L. neavei. His illustrations show one of the parasites in a cell with no nucleus. Probably it was L. caulleryi. We placed 21 young pheasants, 26 turkeys, 7 domestic chickens and 20 ducks in adjacent pens at the edge of woods where transmission of L. simondi was known to be taking place and where birds with L. bonasae, L. danilewskyi, L. dubreuili,L.fringillinarum, and possibly other species were present. All ducks became infected with L. simondi during the 2-6 weeks they were under observation. Infection was not apparent in any of the other birds. Guinea fowl were kept outdoors during the summer near infected grouse, ducks and passeriform birds but parasites were never seen in them. Stephan (1922) transferred blood of geese harbouring L. anseris to turkeys, pigeons, chickens, sparrows, geese and a duck. Gametocytes were found only in the geese and the duck following the inoculation. Mathis and Ltger (191Ob) noted that ducks, geese, turkeys, guinea fowl and pigeons did not become infected although they were kept in a yard with chickens infected with L. sabrazesi and L. caulleryi. Our results suggest that the guinea fowl is an unsuitable host for the above-mentioned four species although the attraction of the vectors to the guinea fowl was not assessed. The limited observations suggest that feeding preferences of vectors rather than resistance of the avian host may explain the absence of parasites from certain species of birds. Research on the feeding behaviour of insects that are suitable hosts and experimental cross infections are essential.

O N SPECIES OF L E U C O C Y T O Z O O N G.

35

EPIZOOTIOLOGY

Observations (Chernin, 1952b) on ducks infected with L. simondi have shown how the occurrence of more than one vector, preference of the vectors for ducks, the feeding behaviour (Bennett, 1960; Fallis and Bennett, 1966), longevity and flight range of vectors (Bennett, 1963), contributed to transmission and a high incidence of the parasite. A similarly high incidence of L . .fringiIIinarum is achieved in other ways. This species occurs in several kinds of birds, and develops in several species of simuliids which seem to show little preference for one bird rather than another. Incidence in young and old birds can differ among species depending on their nesting habits. Birds which nest above ground level, and especially those which remain in the nest for long periods, are likely to become infected while they are in the nest because several ornithophilic simuliids appear to feed by preference in the forest canopy (Bennett, 1960). A high incidence is likely to be found, therefore, in young robins which nest above ground and in crows which remain in the nest for a long time. In contrast, a low incidence in young white-throated sparrows which nest on the ground is understandable. Prevalence and incidence of species of Leucocytozoon will be influenced by the specificity of the parasites for the avian and insect hosts. Little is known about the former but several simuliids which are hosts for L.fringiIIinarum are also suitable for L. dubreuili, danilewskyi, berestnefi and bonasae. Studies on specificity are needed and will be most meaningful if methods of Tarshis of inducing newly emerged simuliids to feed in the laboratory can be used for other species. V. ULTRASTRUCTURE

Ultrastructural studies have thus far been restricted to stages of L. simondi in the avian host and in the simuliid vector (Desser, 1970a, b, c, 1972a, b, 1973; Desser and Wright, 1968; Desser el al., 1970; Aikawa et al., 1970; Sterling and Aikawa, 1973). A.

HEPATIC SCHIZOGONY

Knowledge of hepatic schizogony is incomplete as the changes which occur prior to the formation of cytomeres have not been observed. Maturing schizonts consist of several large electron-dense multinucleate cytomeres. Each cytomere is bounded by a trilaminar plasma membrane and lies within a membranebounded vacuole in the cytoplasm of the hepatocyte (Fig. 53). Extensive invagination and multiple cleavage of the cytomeres culminates in the production of uninucleate merozoites. Each of the latter is bounded by a single trilaminar plasmalemma and contains a large central nucleus, a mitochondrion with vesicular cristae, and paired electron-dense rhoptries and micronemes associated with three apical rings. A second, less frequently observed schizont contains many small, somewhat irregular inclusions interspersed in the hepatocyte cytoplasm. This type of schizont may produce the syncytia which give rise to the megaloschizonts in phagocytic cells (Desser, 1967), although this seems

36

A . M U R R A Y FALLIS, S H E R W I N s . DESSER AND RASUL A . K H A N

FIG.53. Mature hepatic schizont with several cytomeres containing merozoites and some binucleate syncytia. Cytomeres lie within membrane-bounded vacuoles, separated from each other and from the hepatocyte cytoplasm. (HN=hepatocyte nucleus) x 12000.

unlikely as studies of impression smears by light microscopy suggest that merozoites and syncytia may be released by the same schizont. B.

MEGALOSCHIZOGONY

Syncytia released from hepatic schizonts undergo prolific development in RES cells, which become grossly hypertrophied. These parasitized cells are termed megaloschizonts (Fig. 54). Study by light microscopy sometimes reveals two or more syncytia in them. Possibly they enter the cell at different times. This would account for portions of megaloschizonts containing merozoites and other portions showing less advanced development. Thus far cells with the developing syncytia prior to cytomere formation have not been available for electron microscopy and consequently details of cytomere formation are unknown. Young megaloschizonts are separated from the host cytoplasm by a double membrane and contain numerous cytomeres bounded by a plasma membrane. With further development the cytomeres expand, invaginate, and segment. Thickenings form on the plasmalemma of the cytomeres and paired

O N SPECIES OF L E U C O C Y T O Z O O N

37

FIG.54. Young megaloschizontcontaining characteristic, enlargedhost nucleus (N). Several round cytomeres (Cy) lie within the hypertrophied cytoplasm of the host cell ~ 3 6 0 0 . FIG.55. Female merozoite with dense cytoplasm containing many ribosomes x 34200. FIG. 56. Male merozoite containing mitochondrion and electron dense rhoptry (arrow). Note that the merozoites are bounded by a single membrane x 34200.

38

A . MURRAY FALLIS, SHERWIN

s.

DESSER AND RASUL A . KHAN

electron-dense rhoptries form adjacent to these areas. Nuclear division by multiple fission and cytoplasmic segmentation continues until merozoites are formed. The process of merozoite formation by multiple cleavage resembles that seen in hepatic schizogony. Merozoites of megaloschizonts, like those from the hepatic schizonts, are bounded by a single trilaminar membrane and contain a nucleus, a mitochondrion, electron-dense paired rhoptries and micronemes, and three polar rings. Unlike merozoites from hepatic schizonts, two types ofmerozoitescanbe distinguished by the density of ribosomes in their cytoplasm. It was suggested (Desser, 1970a) that the moredensemerozoites are female while the lighter are male (Figs 55, 56). Some megaloschizonts contain both types. Yang et al. (1971) found male and female gametocytes in ducklings inoculated with single megaloschizonts. Megaloschizonts are surrounded by a capsule, the outermost layer of which is fibrous. Beneath this is a thick filamentous zone from which numerous vesicles appear to be pinched off into the hypertrophied cytoplasm of the host cell which is bounded by a trilaminar plasma membrane. The enormous hypertrophy of the nucleus and cytoplasm of the infected cell appears to be a reaction to the rapidly growing parasite. This results in a vast increase in the nuclear chromatin of the host cell and the presence of extensive granular endoplasmic reticulum and numerous mitochondria in the hypertrophied cytoplasm. Nuclear hypertrophy has been observed also in hepatic and renal schizonts of L. fringillinarum, dubreuili, bonasae and danilewskyi (see Khan and Fallis, 1970a; Newman, 1970;Khan, unpublished) but it is less pronounced. C.

GAMETOCYTOGENESIS

Merozoites from hepatic schizonts enter polychromatic and mature erythrocytes and develop into round gametocytes (Fig. 57). Inside the erythrocyte, merozoites are surrounded by a membrane of host origin. As the parasites increase in size electron-dense, particulate material accumulates between the plasma membrane of the parasite and the surrounding host membrane. Small cisternae of endoplasmic reticulum become associated with these areas. Mature gametocytes are invested by three distinct membranes. Beneath the outermost membrane, presumably derived from the plasmalemma of the host cell, lies the plasma membrane of the parasite. Beneath this and separated by a space, lie two closely apposed trilaminar membranes (Desser et al., 1970; Sterling and Aikawa, 1973). Macrogametocytes are distinguished from the microgametocytes by their dark appearance due to the densely packed ribosomes and large accumulations of homogeneous dense material (Fig. 58). Sterling and Aikawa (1973) also observed this material in dilated cisternae of endoplasmic reticulum in macrogametocytes ofL. simondi.Trefiak and Desser (1 973) suggested that this material may act as a precursor of the crystalloid inclusions which are seen soon after zygote formation. Invaginations containing host cytoplasma and membrane-bounded vacuoles enclosing granular material seen occasionally in developing gametocytes are

FIG.57. Polychromatic erythrocyte containing a partially developed round gametocyte. The host cell nucleus (N) is displaced by the parasite. The parasite’s nucleus (*) is invested by a double membrane and its cytoplasm contains several membrane profiles x 38000. FIG.58. Blood cell containing a maturing macrogametocyte (MA) and a younger microgametocyte (MI). Note the characteristic dense appearance of the female due to closely packed ribosomes and amorphous dense material scattered throughout the cytoplasm x 26 600. FIG.59. Distal portion of the cytoplasmic extension of a leucocyte containing an elongate gametocyte. Note the microtubule (M) and the spirally arranged electron-dense banding (arrows) x 28 500.

40

A . MURRAY FALLIS, S H E R W I N S . DESSER A N D R A S U L A . K H A N

suggestiveof pinocytotic uptake of host material. Aikawa et al. (1970) and Sterling and Aikawa (1973) observed specific openings or cytostomes on the surface of L . simondi gametocytes but were unable to demonstrate clearly their role in uptake of nutrients. Large invaginations of the surface membranes were not associated with cytosomal rings. Sterling and Aikawa (1973) suggested that this may indicate “. . . a transience of this structure in Leucocytozoon”. Merozoites from megaloschizonts develop exclusively in leucocytes, predominantly lymphocytes and monocytes, and become the elongate gametocytes. The multilaminate pellicle of the mature elongate gametocytes resembles that in the round forms. Elongation of the host cell begins when the parasite is small and is not caused directly through physical distortion by the parasite. Observations on the early development of elongate gametocytes suggest that centrioles in a cell are stimulated by the parasite to form microtubules which become polarized and distort the host cytoplasm, resulting in the formation of the characteristic cytoplasmic extensions. A peculiar electron-dense “spiral banding” perpendicular to the long axis of the gametocytes was observed by Desser et al. (1970) (Fig. 59) and more recently by Sterling and Aikawa (1973) who described it as regularly spaced subunits “30-40 m p [nm]” in diameter, joined by an electron-dense material. Bundles of microtubules have also been observed in the cytoplasm of immature and mature elongate gametocytes, running parallel to the long axis of the parasite. The presence of well developed mitochondria and Golgi complexes in the residual host cytoplasm of infected leucocytes suggests active metabolism and contrasts sharply with the relatively “empty” appearance of erythrocytes containing mature round gametocytes. The rapid disappearance of the majority of round gametocytes in primary infections and their tendency to exflagellate rapidly may be related to the depletion of metabolites from their host cells, which are reduced to empty shells. The presence of elongate gametocytes in actively metabolizing cells may explain their more or less continual appearance throughout the chronic period of an infection. They show little tendency to exflagellate; their function is not understood. D.

EXFLAGELLATION

Aikawa et al. (1970) studied the ultrastructural changes before and during microgametogenesis in L . simondi. They noted that prior to exflagellation the microgametocyte was bounded by a trilaminar plasma membrane beneath which lay two closely apposed membranes. Before the onset of exflagellation the extracellular gametocyte underwent a peculiar process whereby a large portion of cytoplasm and nucleus of the parasite protruded through an interruption in its membranes. Desser (unpublished) confirmed these observations in vitro with the light microscope. He observed that the male and female gametocytes escaped from their host cells almost immediately after withdrawal of infected blood and that a portion of their contents flowed out through a small opening in the pellicle of each. A small “residual body” remained attached to the larger spherical portion of the extruded material at the conclusion of the process.

O N SPECIES OF

LEUCOCYTOZOON

41

FIG.60.Transection throughabnormal microgametewith one typical axoneme and adjacent disorganized microtubules (circled) x 47 500. FIG.61. Transection through distal portion of microgamete with two axonemes x 50 500. FIG.62. Longitudinally sectioned microgamete illustrating the apparent intertwining of the 2 axonemes x 45 700.

Aikawa et al. (1970) observed that the inner membranes of the transforming microgametocytes were discontinuous and the interruptions were more or less regular. The nuclear membrane disappeared and the chromatin appeared as small peripheral condensations which became dispersed in the cytoplasm and were later reinvested by membrane. These correspond, presumably, to the units referred to above. Axonemes formed and became closely associated with the newly formed “mini-nuclei” in the peripheral cytoplasm. The axonemes extended towards the surface of the microgametocyte to form primary flagellar

42

A . M U R R A Y FALLIS, SHERWIN

s.

DESSER AND R A S U L A . K H A N

buds into which the axonemes and chromatin masses migrated. From the primary flagellar buds, secondary buds, each of which contained a single axoneme and nucleus, grew out to form the microgametes. Aikawa et al. (1970) described the microgametes as long, thread-like structures, containing a single axoneme with a dense, hook-shaped nucleus extending from the anterior end to the midbody. This observation differs from the interpretation of Garnham et al. (1967) who described a single axoneme and a centrally positioned nucleus in microgametes of Leucocytozoon marchouxi. Aikawa et al. (1970) indicated that there were aberrant or “pathological” forms with two or more axonemes but that the most prevalent type contained one axoneme. In our experience the majority of microgametes contained double axonemes (Figs 60, 61, 62); moreover, prolonged study of living and fixed and stained microgametes revealed a central dense nucleus unlike that illustrated by Aikawa et al. who said the nucleus lay towards the anterior end and reflexed at the tip in a hook-like fashion. Clarification of the finerstructure of the microgametocyte during the formation of the microgametes and further study of the latter would be of interest. They obviously differ from the apparently simpler microgametes of Plasmodium spp. (Garnham et al., 1967). E.

OOKINETE

Approximately 5-10 h after fertilization, the zygotes elongate to form motile ookinetes (Desser and Fallis, 1966). Mature ookinetes are invested by a trilaminar plasma membrane beneath which is a fibrillar zone. Below this and forming the inner surface of the pellicle is a second continuous membrane-like layer which cannot be resolved as trilaminar. The pellicle measures approximately 40 nm in thickness. The specialized apical region is modified into a thickened, cap-like structure (Fig. 63). The innermost layer is interrupted at the apex by a dense cylindrical structure which differs from the classical “conoid” seen in the Sporozoa (Scholtyseck et al., 1970). The pellicle in the apical region appears wavy and the inner membrane-like layer appears alternately thick and thin in transverse sections. Below this inner layer in the cap region is a subpellicular space in which several elongate, strut-like, electron-opaque bodies lie. Situated immediately beneath the pellicle and extending along the length of the ookinete is a ring of approximately 70 microtubules. Numerous elongate, electron-dense micronemes extend anteriorly from the prenuclear region towards the apex of the ookinete (Fig. 63). The cytoplasm contains lipid droplets, mitochondria, granular inclusions and two or more large areas of crystalloid material (Fig. 64). The latter correspond to the large “vacuoles” seen in methanol-fixed, Giemsa-stained ookinetes. Their appearance and protein-lipid composition resemble inclusions in ookinetes of Plasmodium gallinaceum and Parahaemoproteus spp. (Trefiak and Desser, 1973). F.

OOCYST

Following penetration into the midgut epithelium of the simuliid vector, ookinetes of L. simondi round up beneath the basal lamina and transform into spherical oocysts. Young oocysts are surrounded by an irregular granular

O N SPECIES OF L E U C O C Y T O Z O O N

43

FIG.63. T r a n s d o n through the apical cap of an ookinete. Beneath the “wavy” plasma membrane is a fibrillar zone and below this, an alternately thick and thin layer. Approximately 35 microtubules ring the peripheral cytoplasm and lie immediately beneath the circumpolar “anterior struts” (*). Numerous electron-dense micronemes lie in the cytoplasm ~43700.FIG.64. Portion of crystalloid inclusion in an ookinete consists of closely packed, electron-dense particles arranged randomly x 43 600.

electron-dense capsule and contain several concentric lamellae of granular endoplasmic reticulum which surround a large central core of crystalloid material. Numerous dividing nuclei with microtubular spindle fibres are seen in the peripheral cytoplasm. In more advanced oocysts, the trilaminar plasma membrane surrounding the parasite becomes intermittently doubled and “budlike” outgrowths occur at these sites. The crystalloid core becomes dispersed in the cytoplasm and some of it moves into each forming sporozoite which grows at the expense of the residual cytoplasm (Fig. 65). G . SPOROZOITE

Approximately 50 slender sporozoites are formed in each oocyst of L. simondi. The sporozoite is surrounded by a pellicle consisting of a trilaminar outer membrane separated by a narrow fibrillar zone from an inner thickened layer comprised of two closely apposed membranes. Immediately below the membranes, approximately 35 microtubules ring the peripheral cytoplasm of the sporozoite (Fig. 66).Sporozoites possess an apical pore which is surrounded by two electron-dense polar rings, but no conoid as stated by Desser (1970b). Large electron-dense paired structures, the rhoptries, originate anterior to the

44

A. M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

FIG.65. Maturing oocyst containing sporozoites associated with residualcytoplasm (R). Each sporozoite contains a crystalloid inclusion (*) (T= tracheole) x 12000.

nucleus and their ducts empty to the outside via the apical pore (Fig. 67). The cytoplasm contains one or more mitochondria and many dense ellipsoidal granules. Aggregations of crystalloid are often seen anterior and posterior to the centrally located nucleus. Choptiany (1972) found that sporozoites of L. simoiidi accumulated predominantly in the posterior region of the bulbous lobe of the salivary glands of the vector, Simuliimz rzrgglrsi (Fig. 68). Penetration by the parasites is probably facilitated by the absence of pigment cells and the comparatively thin basal lamella in this region of the gland. Most intracellular sporozoites were not surrounded by host membrane, although occasionally several parasites were enclosed in a continuous, highly folded, membranous vacuole. The mechanism(s) employed by the motile stages of haemosporidian parasites for locomotion has not been clearly elucidated. Fallis and Bennett (1962) noted the gregarine-like movement of ookinetes. Desser (I97Ob) postulated that the flexing movements displayed by sporozoites ofL. simondimay be due to differential shortening of their subpellicular microtubules. Ookinetes exhibit slow flexing movements and marked forward locomotion without perceptible

O N SPECIES OF

LEucocYrozooN

45

FIG.66. Transection through anterior region of sporozoite illustrating the approximately 35 subpellicular microtubules and the electron-dense micronemes x 43 700. FIG. 67. Longitudinal section through anterior end of sporozoite. Note paired rhoptries (*) with duct of one emptying through apical polar ring (P) x 38 000. FIG. 68. Section through salivary gland of Simulium rugglesi with numerous sporozoites in the lumen (G=gland cell) x 4500.

46

A. MURRAY FALLIS, SHERWIN

s.

DESSER AND R A S U L A. K H A N

alteration in their pellicles. Pellicular folds have been observed electronmicroscopically in both sporozoites and ookinetes of L. simondi (Desser, unpublished) and conceivably the formation of these submicroscopical folds from anterior to posterior is responsible for the locomotion as described for extracellular haemogregarines (Desser and Weller, 1973). Similar folds have been observed in ookinetes of P . berghei (Garnham et al., 1969). The ultrastructure of L. simondi is generally similar to that of comparable stages of other Haemosporina. However, the following features, if present in other species of the Leucocytozoidae, will distinguish them from species of the Plasmodiidae and Haemoproteidae. Individual cytomeres of hepatic and megaloschizonts of L. simondi are surrounded by membranes whereas in exoerythrocytic schizonts of Plasmodium spp. and Huemoproteus spp. the parasites are isolated from the host cytoplasm by a single membrane surrounding all of them (Bradbury and Galucci, 1972; Sterling, 1972). Merozoites of L. simondi and those of renal schizonts of L. dubreuili (Wong and Desser, unpublished) are bounded by a single trilaminar membrane, in contrast to the rigid pellicle and subpellicular microtubules characteristic of merozoites of species of Plasnwdium and Haemoproteus. Tiny orifices associated with feeding (cytosomes or micropores), commonly encountered in merozoites of species of the latter genera (Aikawa, 1971; Bradbury and Galucci, 1971; Sterling, 1972), were not observed (Desser et al., 1970; Desser, 1973) in merozoites of L. simondi. Cytostomes have been found in gametocytes of the latter but do not appear to play an active role in the uptake of host cytoplasm (Sterling and Aikawa, 1973). Cytostomes have not been observed in any other stage of L. simondi, whereas these structures have been found in gametocytes and sporozoites of Plasmodium spp. (Aikawa, 1971; Garnham et al., 1961; Vanderburg et al., 1967; Terzakis et al., 1966), gametocytes and sporozoites of Haemoproteus spp. (Bradbury and Galucci, 1971; Sterling, 1972; Sterling and DeGuisti, 1974; Klei, 1972), as well as in developing schizonts (Bradbury and Galucci, 1971, 1972) of H. columbae. Trefiak and Desser (1973) observed lipid-protein crystalloid in the cytoplasm of the macrogametocytes of L. simondi. Aggregation of crystalloid into a central core in early oocysts and distribution of a portion of this material to each of the forming sporozoites as seen in L. simondi, occurs also in Haemoproteus metchnikovi (see Sterling and DeGuisti, 1974) and probably in Parahaemoproteus velans (see Desser, 1972a). Crystalloid inclusions have also been found in ookinetes of species of Plasmodium, Haemoproteus and Parahaemoproteus (see Garnham et al., 1969; Galucci, 1971; Desser, 1972b; Trefiakand Desser, 1973). They rarely occur in immature oocysts of Plasmodium spp. (Terzakis et al., 1966; Garnham et al., 1969) and have never been observed in sporozoites of species of the latter (Garnham er al., 1961; Terzakis, 1971; Terzakis et al., 1967; Vanderburg et al., 1967). Trefiak and Desser (1973) proposed that crystalloid inclusions in species of the Haemosporina be divided into two types on the basis of ultrastructural and cytochemical evidence; Type I is lipid-protein in nature and appears as electron-dense, irregularly spherical particles, 25-40 nm in diameter, with individual particles not invested by membrane. Type I1 is probably virus and is characterized by electron-dense, irregularly spherical, membrane-bounded particles with a diameter usually

O N SPECIES O F LEUCOCYTOZOON

47

greater than 40nm. The latter type has been described in early oocysts of Plasmodium gallinaceum (see Terzakis, 1969) and of P. berghei berghei (see Davies and Howells, 1971). Type I crystalloid may serve as an energy reserve and may explain the survival of sporozoites of Leucocytozoon spp. in the blood of the avian host for several days (Khan et al., 1969) whereas sporozoites of Plasmodium spp. which do not possess crystalloid disappear from the blood of the vertebrate host within an hour following injection (Fairley, 1947). Discovery of Type I crystalloid in sporoblast stages of several coccidian species (Porchet-HennerC and Richards, 1969,1971 ;Porchet-HennerCandVivier, 1971 ;Robertsetal., 1972)suggeststhat these inclusions may be a common feature in the sporogonic development of many species of Teleospora.

VI. PATHOGENESIS AND PATHOLOGY Few records of infection with species of Leucocyrozoon and descriptions of the species mention disease. Pathogenesis has been predominantly attributed to infection with L. simondi, L. smithi, and L. caulleryi although Wingstrand (1948) reported a “violent attack of the disease” in 2 young crows infected with L. sakharofi and Garnham (1966) attributed death in weaver birds to an unnamed species. Wickware (1915) described an epizootic with many deaths of ducks in Ontario, Canada. Mortality of ducks and geese was recorded also by Knuth and Magdeburg (1922, 1924), Stephan (1922), and Ivanic (1937). Parasites found sometimes in apparently healthy birds cast some doubt on the pathogenesis of L. simondi. Savage and Isa (1 959) also reported disease in ducks. O’Roke’s studies (1930, 1931, 1934) clearly indicated that L. anatis (=L.simondi) produced an often fatal disease of young ducks. Severely infected birds displayed lethargy, loss of appetite, diarrhaea, laboured breathing, convulsions and ultimately many died. The liver and spleen were markedly hypertrophied and an increasing anemia was attributed to the large number of parasitized erythrocytes. Fallis et al. (1951), Kocan and Clark (1966), and Desser (1967) studied the development of L. simondi in ducks and noted the anaemia and tissue damage associated with the widespread secondary megaloschizonts. The red blood cell volume decreased in several birds by 50% or more. This decrease could not be explained by destruction of parasitized cells only. The anaemia was usually most severe 9-1 5 days after infection. Kocan (1968) found that the number of parasites in erythrocytes would not account for the observed anaemias and concluded that the extensive loss of erythrocytes in L. simondi infections is due to intravascular haemolysis. In a study of the histopathology of ducks infected with L. simondi, Newberne (1957) found hypertrophy, congestion and haemosiderosis in the liver and spleen, and necrotic foci in the liver. Reaction against megaloschizonts was seen in the brain and lungs, but not in the other organs, nor was there reaction against hepatic schizonts or gametocytes. Cowan (1957) and Desser (1967) also described the infiltration of inflammatory cells around megaloschizonts and the resulting necrosis. Briggs (1960) compared gametocytaemia and mor-

48

A. M U R R A Y FALLIS, SHERWIN

s.

DESSER A N D RASUL A. K H A N

tality rates of White Pekin and Muscovy ducklings naturally infected with L. sirnondi. The parasitaemia was lower in the Muscovies and reached a peak later than in the Pekins. Mortality was likewise lower and death occurred later in the Muscovies. The difference, as Briggs indicates, could result from differences in susceptibility and/or differences in the feeding preferences of the vectors. Similar studies which included experimental and natural infections are reported on Black, Mallard and White Pekin ducks by Khan and Fallis (1968). The two wild species were noticeably more tolerant of the parasite. Anderson et al. (1962) noted that only domestic ducks died when they and several wild species were infected experimentally. A highly pathogenic species of Leucocytozoon of chickens, was described by Mathis and LCger (1910b). It has been incriminated as causing epizootics in Thailand (Campbell, 1954), India (Sivadas et al., 1965), Taiwan (Lee et al., 1966a),Japan (Akiba et al., 1958), Burma (Griffiths, 1964),Ceylon (Seneviratna and Bandaranayake, 1963), the Philippines (Manuel, 1969), Singapore (Chew, 1968), Malaysia (Omar, 1968), and Korea (Akiba, 1964). Akiba (1960b) and Akiba and Morii (1967) studied the pathology of the disease in experimentally infected chickens. Clinical symptoms were first observed 12-1 3th days after infection, and were related to the number of sporozoites the bird received (Morii and Kitaoka, 1969). Birds harbouring heavy infections were listless, lost their appetite, discharged diarrhaeic, green faeces, and often died of haemorrhage about 2 weeks post infection. Survivors suffered from acute anaemia due to haemorrhage and erythrocyte destruction. Petechial haemorrhages and oedema were noted in birds with innumerable megaloschizonts which formed thrombi in the vascular endothelium of most of the organs and tissues examined. Inflammatoryresponse to themegaloschizonts was observed in many tissues. Wingstrand (1947) described stages in the schizogony and gametogony of L. sakharofi from naturally infected, hooded crows in Sweden. Two juveniles shot during the spring harboured heavy parasitaemias and numerous megaloschizonts up to 480 pm in diameter in the spleen, pituitary and thyroid glands, and gonads. Congested spleens 60mm or more long and 10mm or more broad and containing numerous megaloschizonts were present in other nestlings with the disease. Haemosiderin in the liver and spleen and inflammatory and necrotic foci in the liver were noted. Many gametocytes were in the blood vessels. Adult crows shot during autumn contained some gametocytes, but schizogonic stages were not seen. He concluded from observations on naturally infected birds, that the parasite was pathogenic and that mortality (if any) occurred in the nestlings. Leucocytozoon smithi has long been considered a pathogen of turkeys. Stephan (1922) discovered a heavy parasitaemia in a turkey that had died suddenly. The parasite was the suspected cause of death as other pathogens were not found. Skidmore (1932) noted heavy mortality in turkeys in Nebraska, which he related to the presence of L. smithi. Bacteria were excluded as causal agents. Johnson et al. (1938) also described epizootics of L. smithi in turkeys in Virginia. Bacterial examinations of dead birds yielded negative results, as did attempts at experimental transmission with blood and tissues. From post

O N SPECIES OF L E U C O C Y T O Z O O N

49

mortem examinations these authors suggested that death might have been caused by “circulatory obstruction by large numbers of these parasites resulting in anaemia of some of the vital organs”. The capillaries were crowded with gametocytes, but schizonts were not seen in the tissues of 40 turkeys. The symptoms in heavily infected birds were somewhat similar to those displayed by ducks infected with L . sirnondi, namely loss of appetite, emaciation, lethargy, difficulty in breathing, anaemia, enlarged liver and spleen, and congested lungs and heart. Newberne (1955) studied the histopathology of L. smithi in turkeys harbouring chronic infections. He found small schizonts in hepatic parenchymal cells, and some congestion in the viscera. He noted some lymphocytic infiltration but believed it was not necessarily caused by the parasite. No cellular reaction was associated with gametocytes. Haemosiderin in Kiipffer cells was believed to have come from broken down erythrocytes. Banks (1943), Savage and Isa (1945), Travis et af.(1939), West and Star (1940), Jones et af.(1972) and Stoddard et al. (1952) reported mortality in turkey flocks which they attributed to L. srnithi. Byrd (1959) conducted a study of naturally and experimentally infected wild turkeys and concluded that in native wild and pen-raised turkeys in one area in Virginia, “Leucocytozoon probably should be considered an innocuous organism”. The evidence linking epizootics in turkeys with L. srnithi infections is conflicting. Descriptions of the pathology differ. Possibly other factors in combination with the parasite are responsible for death. In a recent publication Noblet et af.(1972) cite a personal communication from W. Derieux that the disease in turkeys “is often potentiated by concurrent infections with other diseases such as fowl cholera”. Careful study of experimentally infected turkeys is necessary. The pathogenicity of Leucocytozoon spp. of grouse and of capercaille is also in doubt. Clarke (1934, 1935a), finding gametocytes of Leucocytozoon bonasae in most grouse he examined in Ontario, suspected it might be a cause of death. Fallis and Hope (1 950) failed, however, to produce conclusive evidence that the parasite alone was the pathogen. Borg (1953) described hepatic schizogony in naturally and experimentally infected grouse chicks and juveniles. His careful studies provided no support for the theory that leucocytozoonosis was responsible for the mortality in grouse. Erickson (1953) concluded likewise and Newman (1970) obtained no evidence of pathogenicity. Similarly, studies of naturally and experimentally infected passeriform birds by Khan and Fallis (1970a) revealed neither clinical signs nor mortality although many schizonts were in the liver and kidneys and high parasitaemias were noted. Recently mortality in parakeets in Germany and Great Britain has been associated with “aberrant leucocytozoonoses” (Walker and Garnham, 1972; Borst and Zwart, 1972). Histological examination of dead birds revealed megaloschizonts in the tissues and a pathological picture not unlike that associated with infections with L. simondi and L. caulleryi. Available data suggestthat the most pathogenic species have megaloschizonts in cells of the reticulo-endothelial system; i.e. L . simondi, L. caulleryi, L.

50

A. MURRAY

FALLIS,

SHERWIN S . DESSER A N D R A S U L

A.

KHAN

sakharoji. Pathogenicity of L. bonasae, L. lovati, L. smithi, L.fringillinarum and L. dubreuili with schizogony restricted to cells in the hepatic and renal epithelium seems to be less severe. Pathogenicity has been evaluated solely on gross appearances and some histological examinations. A priori biochemical and pathophysiological damage might be expected in view of studies by Maegraith and colleagues on species of Plasmodium (1968). Domestic birds appear to be affected more severely than wild species. The lesser effects on the latter may be nevertheless damaging to them in their natural habitats by making them more susceptible to other pathogens, environmental stresses and predation.

VII. TREATMENT PREVENTION AND CONTROL

Mathis and LCger (191 1b) reported no change in the number of gametocytes of L. sabrazesi in domestic chickens receiving quinine daily. O’Roke (1934), Coatney and West (1938) and Fallis (1948) using quinine, paludrin, atebrin and sulphamerazine were unsuccessful in preventing, or curing, infections caused by L. simondi. Seneviratna and Banaranayake (1963) claimed that administration of quinine and other antimalarials including pyrimethamine was ineffective against L. caulleryi infection in Ceylon. Akiba el al. (1963,1964) achieved remarkable success in preventing leucocytozoonosis in chickens in Japan by administering 0.5-1 .O ppm of pyrimethamine in the food. Good results were also obtained with sulphadimethoxine (50 ppm). In 1967 a strain of L. caulleryi produced an epizootic which did not respond to pyrimethamine but simultaneous administration of pyrimethamine (1 ppm) and sulphadimethoxin (10 ppm) was effective (Akiba, 1970). Lee et af.(1966a, b) in Taiwan studied the effectiveness and side effects of the same drugs over prolonged periods on chickens infected with L. caulleryi. Their data confirmed the Japanese workers’ results. Prolonged administration of pyrimethamine and sulfadimethoxine, in the dosages employed, apparently caused no side effects. In an attempt to control the vector, Culicoides arakawae, Hori et al. (1964) sprayed a repellent (DA-1A-7) inside chicken houses and over the body of the birds. The procedure resulted in reduced biting by the midges. Kitaoka et al. (1965) observed a decrease in mortality and incidence among birds sprayed with repellents. VIII. IMMUNITY Ducks which survived primary infections and were exposed to continued reinfection ofL. simondi lapsed into a chronic phase characterized by low parasitaemias and few tissue stages. Thus infection initiated a state of premunition (Fallis et al., 1951). Birds harbouring chronic infections and isolated from the simuliid vectors for some time often became heavily reinfected and died of acute leucocytozoonosis when re-exposed. A similar situation resulted when ducks infected during one summer were re-exposed to infection the following

ON SPECIES O F LECJCOCYTOZOON

51

year. Protection is apparently dependent on the continual introduction of sporozoites into the birds. Experimental work on the immunological aspects of Leucocytozoon disease is scanty. Kocan andClark( 1966)studied the anaemia associated with infections with L. simondi as well as the mechanism of erythrocyte destruction (Kocan, 1968).Anaemia was coincident with the appearance of young gametocytes and was most pronounced during early patency and the period ofpeak parasitaemia. The volume of erythrocytesincreased gradually to the normal level as the parasitaemia declined to a chronic state. Kocan and Clark (1966) suggested that the number ofparasites would not account for the observed anaemia. Subsequently, Kocan (1968) noted that the anaemia was not due to erythrophagocytosis in the spleen and bone marrow, nor was it apparently due to destruction by autoantibody. An anti-erythrocyte factor was found in the gamma fraction of the serum of acutely infected ducks which agglutinated and haemolyzed normal as well as infected duck erythrocytes. Titers of anti-erythrocyte factor were determined using normal erythrocytes. These cells agglutinated below 25°C and were haemolyzed at 37" and 42°C. Kocan concluded that the red cell loss in L. simondi infections resulted from intravascular haemolysis. Lee et aZ. (1969) observed that chickens that had recovered from primary infections with L. caulleryi resisted reinfection. Morii and Kitaoka (1970) found that experimentally infected young chickens were less resistant to reinfection than older birds. They observed merozoites in the peripheral blood of chickens challenged with sporozoites following repeated primary inoculations with merozoites. Gametocytes, however, failed to develop in these birds. The level and duration of parasitaemia in primary infections in normal chickens were similar to those observed in bursectomized birds, but the latter were susceptible to reinfection. Splenectomy performed 2 days before or 14 days after inoculation had little effect on the intensity and duration of parasitaemia. Morii (1972) found soluble antigens in the sera of chickens 10-15 days after inoculation with sporozoites. The highest titer of serum-soluble antigens was recognized two days prior to the peak in parasitaemia and increased proportionately with the number of sporozoites inoculated. Precipitating antibodies against antigen prepared from schizonts were demonstrated on the 17th day, and against antigen from merozoites and gametocytes on the 21st day after infection. The antibody reacted specifically with L. cauZleryi antigen. Cross reactions were not observed with antigens prepaied from related Sporozoa.

IX. CULTIVATION Successful in vitro cultivation of species of Leucocytozoon should facilitate studies of life histories and to some extent offset difficulties encountered in keeping hosts and vectors for use experimentally. Yang (1971) grew megaloschizonts of L. simondifor 5 days following introduction into Eagle's Minimum Essential Medium supplemented with 10 % foetal calf serum. Growth occurred in macrophages (Fig. 52). The cultured parasites were infective to ducks and elongate gametocytes appeared, followed by round forms. The parasitaemia which followed the inoculation of the hepatic schizonts showed an opposite

52

A . MURRAY FALLIS, S H E R W I N S . DESSER A N D RASUL A . K H A N

pattern with the round gametocytes appearing first. This sequence would be expected if merozoites from megaloschizonts grow into elongate gametocytes or into hepatic schizonts and those from hepatic schizonts into round gametocytes. Cultures of hepatic cells which had been inoculated 10 days before with sporozoites contained no recognizable hepatic schizonts but infective parasites, probably surviving sporozoites, were present as ducks became infected when inoculated with the cultures. Attempts to culture hepatic schizonts commencing with an inoculum from an infected liver were unsuccessful. Fertilization of the macrogamete and formation of the ookinete takes place in blood held at room temperature (Fallis and Bennett, 1961 ; Roller and Desser, 1973b) but transformation to an oocyst in vifro has not been achieved.

X. SUMMARY Readers will perceive the progress toward an understanding of these parasites and, at the same time, the uncertainty concerning the status of several species and their biology. Studies of life cycles and taxonomy, although not fashionable, are clearly needed and are challenging, the more so because research to discover ways of maintaining hosts and vectors often must precede such studies. Knowledge of life histories is basic to work on the biochemistry and physiology of the organisms and to experimental studies to assess specificity, pathogenesis, and immunity. Genetics is unexplored and cytological observations are reported on only one species. Intriguing epizootiological problems requiring ecological investigations of avian and insect hosts in different parts of the world await attention. Furthermore, these parasites could be used as models for research pertaining to the biology of cells. Information should be especially relevant to an understanding of the related coccidian and malaria parasites. Current interest in several places leads to the expectation of interesting discoveries during the next decade.

ACKNOWLEDGMENTS We are grateful to the Medical Research Council, Canada, for financial support for some of the research reported herein and to Mrs G. Weller and other colleagues for assistance in preparing the manuscript. REFERENCES Aikawa, M. (1 971). Plasmodium: The fine structure of malarial parasites. ExplParasit. 30, 284-320. Aikawa, M., Huff, C. G. and Strome, C. P. A. (1970). Morphological study of microgametogenesis of Leucocytozoon simorrdi. J. Ultrastruc. Res. 32, 43-68. Akiba, K. (1960a). Studies on the Leucocytozoon found in the chicken in Japan 11. On the transmission of L . caulleryi by Culicoides arakawae. Jap. J. vet. Sci. 22, 309-31 7 . Akiba, K. (1960b). Studies on Leucocytozoon disease of chickens IV. Relationship between gametogony of L. caulleryi Mathis and Leger 1910, in experimentally infected chickens and its clinical symptoms and haematological changes. Jap. J . vet. Sci. 22,461462. Akiba, K. (1964). Leucocytozoonoses in Japan. Bull. 08 int. Epizoot. 62,1017-1022.

O N SPECIES O F L E U C O C Y T O Z O O N

53

Akiba, K. (1970). Leucocytozoonosis of chickens. Natn. Inst. Anim. Hlth. Q., Tokyo 10 (SUPPI.),131-147. Akiba, K. and Morii, T. (1967). Influence of suspending fluid on the viability of sporozoites of Akiba (=Leucocytozoon).Jap. J. vet. Sci. 29 (suppl.), 48-49. Akiba, K., Kawashima, H., Inui, S. and Ishii, S. (1958). Studies on Leucocytozoon of chickens in Japan I. Natural infection of L . caulleryi. Bull. natn. Inst. Anim. Hlth 34, 163-180. Akiba, K., Morii, S., Ebisawa, S., Nozawa, S. and Minai, T. (1963). Field trials for the prevention of Leucocytozoon caulleryi infections in chickens by the use of pyrimethamine, sulfisomezole, sulfadimethoxine and furazolidone. Natn. Inst. Anim. Hlth Q., Tokyo 3, 188-197. Akiba, K., Ebisawa, S., Nozawa, S., Komigama, T. and Minai, T. (1964). Preventative effects of pyrimethamine and some sulfonamides on Leucocytozoon caulleryi in chickens. Natn. Inst. Anim. Hlth Q., Tokyo 4,222-228. Akiba, K., Inui, S. and Ishitani, R. (1971). Morphology and distribution of intracelMar schizonts in chickens infected experimentally with Akiba caulleryi. Natn. Inst. Anim. Hlth Q., Tokyo 11, 109-121. Al-Dabagh, M. A. (1964). The incidence of blood parasites in wild and domestic birds of Columbus, Ohio. Am. Midl. Nat. 72, 148-151. Anderson, 3. R., Trainer, D. 0. and DeFoliart, G. R. (1962). Natural and experimental transmission of the waterfowl parasite Leucocytozoon simondi M. & L., in Wisconsin. Zoonoses Research 9, 155-164. Arcay-Peraza, L. (1968). Hellazo de un Leucocytozoidae (Protozoa, Sporozoa) en reptiles (Iguana iguana iguana). Acta Cientifica Venezolano 19,46. Atchley, F. 0. (1951). Leucocytozoon andrewsi n. sp. from chickens observed in survey of blood parasites in domestic animals in South Carolina. J. Parasit. 37, 483-488. Aubert, P. and Heckenroth, F. (191 1). Sur trois Leucocytozoon des oiseaux de Congo francais. C. r. Skanc. SOC.Biol. 70,958-959. Baker, J. R. (1958). Leucocytozoon spp. in some Hertfordshire birds. Nature, Lond. 181, 205. Baker, J. R. (1970).Transmission of Leucocytozoon sakharofi in England by Simulium angustitarse. Parasitology 60,417-423. Balfour, A. (1906). Report of a travelling pathologist and protozoologist. Second Report Wellcome Research Laboratory, Khartoum, 183. Balfour, A. (1908). Report of travelling pathologist and protozoologist. Third Report Wellcome Research Laboratory, Khartoum, 157-1 65. Banks, W. C. (1943). Leucocytozoon smithi infection and other diseases of turkey poults in central Texas. J. Am. vet. med. Ass. 102,467-472. Barrow, J. H. and Miller, H. C. (1964). A fluorescznt waterfowl Leucocytozoon antibody in rabbits. J. Protozool. 11 (suppl.), 18. Barrow, J. H., Jr., Kelker, N. and Miller, H. (1968). The transmission of Leucocytozoon simondi to birds by Simulium rugglesi in Northern Michigan. Am. Midl. Nat. 79, 197-204. Beer, L. (1944). Parasites of the blue grouse. J. Wildl. Mgmt 8,91-92. Bennett, G. F. ( I 960). On some ornithophilic blood-sucking Diptera in Algonquin Park, Ontario, Canada. Can. J . Zool. 38, 377-389. Bennett, G. F. (1963). Use of P32in the study of a population of Simulium rugglesi (Diptera: Simuliidae) in Algonquin Park, Ontario. Can. J. Zool. 41,831-840. Bennett, G . F. and Fallis, A. M. (1960). Blood parasites in birds in Algonquin Park, Canada, and a discussion of their transmission. Can. J. Zool. 38,261-273. 3

54

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

Bennett, G. F. and Laird, M. (1973). Collaborative investigations into avian malarias; an international research programme. J. Wildl. Dis. 9,26-29. Bennett, G. F., Garnham, P. C. C. and Fallis, A. M. (1965). On the status of the genera Leucocytozoon, Ziemann, 1898 and Haemoproteus, Kruse 1890 (Haemosporidiida: Leucocytozoidae and Haemoproteidae). Can. J. Zool. 43,927-932. Berestneff, N. (1904). Uber das Leucocytozoon danilewskyi. Arch. Protistenk. 3, 376-386. Berson, J. P. (1964). Les protozoaires parasites des hkmaties et du systtme histiocytaire des oiseaux. Essai de nomenclature. Revue Elev. 17,43-96. Bhatia, B. L. (1938). “The Fauna of British India Protozoa: Sporozoa”. Taylor and Francis, London. Boing, W. (1925). Untersuchungen iiber Blutschmarotzen bei einheimischen Vogelwild. Zentbl. Bakt. ParasitKunde Abt. I. 95,312-327. Borg, K. (1949). Blodparasites hos vilda honsfaglar i Sverige och nagot om deras betydelse. Nordisk Nord. Vet.Med. 1,199-212. Borg, K. (1953). On Leucocytozoon in Swedish Capercaillie Black Grouse and Hazel Grouse. Berlingska Boktryckeriet, Lund 1-109. Borst, G. H. A. and Zwart, P. (1972). An aberrant form of Leucocytozoon infection in two Quaker Parakeets (Myiopsitta monachus Boddaert, 1783). Z . ParasitKde 40, 131-138. Bradbury, P. C. C. and Galucci, B. B. (1971). The fine structure of differentiating merozoites of Haemoproteus columbae Kruse. J. Protozool. 18, 679-686. Bradbury, P. C. C. and Galucci, B. B. (1972). Observations on the fine structure of the schizonts of Huemoproteus columbae Kruse. J . Protozool. 19,4349. Bray, R. S. (1964). A check list of the parasitic protozoa of West Africa with some notes on their classification. Bull. de I’I.F.A.N. 26,238-315. Breinl, A. (1913). Parasitic protozoa encountered in the blood of Australian native birds. Rep. Aust. Znst. trop. Med. for 1911,30-38. Briggs, N. T. (1960). A comparison of Leucocytozoon simondi in Pekin and Muscovy ducks. Proc. helminth. SOC.Wash. 27, 151-156. Burgess, G. D. (1957). Occurrence ofLeucocytozoon simondi M. and L. in wild waterfowl in Saskatchewan and Manitoba. J. Wildl. Mgmt 21, 99-100. Byrd, M. A. (1959). Observations on Leucocytozoon in pen-raised and free-ranging wild turkeys. J. WiIdl. Mgmt 23, 145-156. Campbell, J. G. (1954). Bangkok haemorrhagic disease of chickens: An unusual condition associated with an organism of uncertain taxonomy. J. Path. Bact. 68, 423. Cardamatis, J. P. (191 1). L‘Haemamoeba ziemanni d’apres les observations faites. Centralbl. Bakt. I Abt. 50,241-245. Carini, A. (1920). Sur un Leucocytozoon d’une chouette du Brtsil. Bull. SOC.Path. exot. 13, 506-508. Chernin, E. (1952a). Parasitemia in primary Leucocytozoon infection. J. Parasit. 38, 499-508. Chernin, E. (1952b). The epizootiology of Leucocytozoon simondi infections in domestic ducks in Northern Michigan. Am. J. Hyg. 56, 39-57. Chernin, E. (1952~).The relapse phenomenon in Leucocytozoon infection of the domestic duck. Am. J. Hyg. 56, 101-118. Chew, M. (1968). Megaloschizonts of Leucocytozoon in the eyes and sciatic nerves of domestic fowl. Vet. Res. 83, 51 8-5 19. Choptiany, Stanley, M. (1972). A cytological study of the salivary glands of adult female Simulium rugglesi Nicholson and Mickel, and observations on the

O N SPECIES OF L E U C O C Y T O Z O O N

55

relationship between the glands and the sporozoita of Leucocytozoon simondi Mathis and Leger. M.Sc. Thesis, University of Toronto, Canada. Clark, G. W. (1964). Frequency of infection and seasonal variation of Leucocytozoon berestnefi in the yellow-billed magpie, Pica nuttali. J. Protozool. 11,481-483. Clark, G . W. (1965). Schizogony and gametocyte development of Leucocytozoon berestnefi in the yellow-billed magpie, Pica nuttali. J. Protozool. 12, 584-589. Clark, G. W. and Swinehart, B. (1969). Avian haematozoa from the offshore islands of Northern Mexico. Bull. Wildl. Dis. Assoc. 5,111-1 12. Clarke, C. H. D. (1934). Causes of mortality of young grouse. Science, N.Y. 80, 228-229. Clarke, C. H. D. (1935a). The dying off of ruffedgrouse. Trans. 21st. Am. Game Conf. 402-405. Clarke, C. H. D. (1935b). Blood parasites ofruffedgrouse(Bonasaumbel1us)andspruce grouse (Canachitescanadensis)with description of Leucocytozoon bonasae n. sp. Can. J. Res. 12, 646-650. Clarke, C. H. D. (1938). Organisms of a malaria type in ruffed grouse, with a description of schizogony of Leucocytozoon bonasae. J. Wildl. Mgmt 2, 146-1 50. Clarke, C. H. D. (1946). Some records of blood parasites from Ontario birds. Can. Fld Nut. 60, 34. Cleland, J. B. (1915). The haematozoa of Australian birds No. 3. Trans. R. SOC. S. Austr. 39, 25-37. Cleland, J. B. (1922). The parasites of Australian birds. Trans.Proc. R. SOC.S. Austr. 46, 85-1 18. Cleland, J. B. and Johnston, T. H. (1911). The haematozoa of Australian birds. J. Proc. R. SOC.N.S. W. 4 5 , 4 1 5 4 4 . Coatney, G. R. (1937). A catalogue and host-index of the genus Leucocytozoon. J. Parasit. 23, 202-212. Coatney, G. R. (1938). Some blood parasites from birds of the Lake Okoboji region. Am. Midl. Nut. 20, 336-340. Coatney, G. R. (1960). Some blood parasites found in birds and mammals from Loei province, Thailand. J, Parasit. 46, 701-702. Coatney, G. R. and Jellison, W. L. (1940). Some blood parasites from Montana birds. J. Parasit. 26, 158-1 60. Coatney, G. R. and Roudabush, R. L. (1937). Some blood parasites from Nebraska birds. Am. Midl. Nat. 18, 1005-1030. Coatney, G. R. and West, E. (1938). Some blood parasites from Nebraska birds 11. Am. Midl. Nut. 19,601-612. Coles, A. C. (1914). Blood parasites found in mammals, birds and fishes in England. Parasitology 7 , 17-61. Commes, Ch. (1918). Leucocytozoon et microfilaria d’un rapace diurne (Astur badius sphenurus). Bull. SOC.Path. exot. 11, 31-34. Cook, A. R. (1954). The gametocyte development of Leucocytozoon simondi. Proc. helminth. SOC.Wash. 21, 1-9. Corradetti, A., Cavalluci, P. and Crescenzi, R. (1941). Incidenze dagli emotozoi delle civette nella Campagna Romana all‘inizio dell’autumno. Revta Parasit. 5, 251. Covaleda, Ortega J. and Gallego Berenquer, J. (1946). Contribucion a1 estudio de algunosLeucocytozoon parasitos de aves espaiiola. Revta ibkr.Parasit. 6,203-224. Cowan, A. B. (1955). The development of megaloschizonts of Leucocytozoon simondi, Mathis and Leger. J. Protozool. 2, 158-167. Cowan, A. B. (1957). Reactions against the megaloschizonts of Leucocytozoon simondi Mathis and Leger in ducks. J. infect. Dis. 100, 82-87.

56

A . M U R R A Y FALLIS, S H E R W I N S . DESSER A N D R A S U L A . K H A N

Danilewsky, V. (1889). “Le parasitologie comparie du sang. I. Nouvelles recherches sur les parasites du sang des oiseaux”. A. Dame, Kharkoff. Danilewsky, V. (1890). Developpement des parasites malariques dans les leucocytes des oiseaux. Annls Znst. Pasteur, Paris 4,427-43 1. Davies, E. E. and Howells, R. E. (1971). A pathogen of the malaria parasite. Trans. R. SOC.trop. Med. Hyg. 65,541. De Lucena, D. T. (1941). Lista dos protozoarios hemoparasitas de aves da regiao neatropica. Rev. Fac. Med. vet. Sao Paul0 2, 33-66. Desser, S. S. (1967). Schizogony and gametogony of Leucocytozoon simondi and associated reactions in the avian host. J. Protozool. 14,244-254. Desser, S . S. (1970a). The fine structure of Leucocytozoon simondi. 11. Megaloschizogony. Can. J. Zool. 48,417-421. Desser, S. S. (1970b). The fine structure of Leucocytozoon simondi. 111. The ookinete and mature sporozoite. Can.J. Zool. 48,641-645. Desser, S. S. (1970~).The fine structure of Leucocytoroon simondi. IV. The microgamete. Can. J. Zool. 48, 647-649. Desser, S. S. (1972a). The fine structure of Leucocytozoon simondi. V. The oocyst. Can. J. Zool. 50,707-71 1. Desser, S. S. (1972b). The ultrastructure of ookinetes of Parahaemoproteus velans (= Haemoproteus velans, Coatney & Roudabush)(Haemosporidia : Haemoproteidae). Can. J. Zool. 50,477-480. Desser, S. S. (1973). The fine structure of Leucocytozoon simond. VI. Hepatic schizogony. Can. J. Zool. 51, 605-610. Desser, S. S. and Fallis, A. M. (1966). A description of the stages of the sporogony of Leucocytozoon simondi. Can. J . Zool. 45,275-277. Desser, S. S. and Weller, I. (1973). A study of the structure, cytochemistry, and locomotion of a species of Haemogregarina from Rana berlandieri.J. Protozool. 20, 65-73. Desser, S. S. and Wright, K. A. (1968). A preliminary study of the fine structure of the ookinete, oocyst, and sporozoite formation in Leucocytozoonsimondi Mathis and LCger. Can.J. Zool. 46,303-31 1 . Desser, S. S. and Yang, Y. J. (1973). Sporogony of Leucocytozoon spp. in mammalophilic simuliids. Can. J. Zool. 51, 793. Desser, S. S., Fallis, A. M. and Garnham, P. C. C. (1967). Relapses in ducks chronically infected with Leucocytozoon simondi and Parahaemoproteus nettionis. Can. J. ZOOI.46,281-285. Desser, S . S., Baker, J. R. and Lake, P. M. (1970). The fine structure ofleucocytozoon simondi. I. Gametocytogenesis. Can. J. Zool. 48, 331-336. Dias, J. A. T. S. (1951). Hematozoaires das aves. Duos novas especies parasitas do Pternistes afer swynnertoni.W. L. Sclater, 1921, Moqambique No. 67,71-92. Dias, J. A. T. S. (1954). Estudos fobre of haematozarios das aves de Moqambique. Bolm SOC.Estud. MoCarnh. 87, 3-14. Doflein, F. (1916). “Lehrbuch der Protozoenkunde” (4th edition). Fischer, Jena. Dorney, R. S. and Todd, A. C. (1960). Spring incidence of ruffed grouse blood parasites. J. Parasit. 46, 687-694. Dutton, J. F., Todd, J. L. and Tobey, E. N. (1907). Concerning certain parasitic protozoa observed in Africa. Ann. trop. Med. Parasit. I , 287-370. Eide, A. and Fallis, A. M. (1972). Experimental studies on the life cycle of Leucocytozoon simondi in ducks in Norway. J. Protozool. 19,414-416. Eide, A., Fallis, A. M., Brinkman, A., Jr., Allen, T. and Eligh, D. (1 969). Haematozoa from Norwegian birds. h b o k Univ. Bergen 6, 1-8.

O N S P E C I E S OF

LEUCOCYTOZOON

57

Erickson, A. B. (1953). Leucocytozoon bonasae in ruffed grouse; its possible relationship to fluctuations in numbers of grouse. J. Wildl. Mgmt 17,536-538. Ewers, W. H. (1967). The blood parasites of some New Guinea birds. Nova Guinea 38, 427-432. Fairley, N. H. (1947). Sidelights on malaria in man obtained by subinoculation experiments. Trans. R. SOC.trop. Med. Hyg. 40, 621-676. Fallis, A. M. (1948). Observations on Leucocytozoon infections in birds receiving paludrine atebrin and sulfamerazine. Can. J. Res. D. 26, 73-76. Fallis, A. M. (1950). Are Leucocytozoon sakharofi Sambon and Leucocytozoon berestnefi Sambon synonymous. Can. J. Res. 28, 1-4. Fallis, A. M. (1965). Protozoan life cycles. Am. Zool.5,85-94. Fallis, A. M. and Bennett, G. F. (1961). Sporogony of Leucocytozoon and Haemoproteus in simuliids and ceratopogonids and a revised classification of the Haemosporidiida. Can. J. Zool.39,215-228. Fallis, A. M. and Bennett, G. F. (1962). Observations of the sporogony ofLeucocytozoon mirandae, L. bonasae, and L. fringillinarum (Sporozoa : Leucocytozoidae). Can. J. Zool. 40,495-400. Fallis, A. M. and Bennett, G. F. (1966). On the epizootiology of infections caused by Leucocytozoon simondi in Algonquin Park, Canada. Can. J. Zool. 44, 101-1 12. Fallis, A. M. and Hope, C. E. (1950). Observations of ruffed grouse in southern Ontario with a discussion of cycles. Can. Fld Nat. 64,82-85. Fallis, A. M., Davies, D. M. and Vickers, M. A. (1951). Life history ofLeucocytozoon simondi Mathis & Leger in natural and experimental infections and blood changes produced in the avian host. Can.J.Zool.20,305-328. Fallis, A. M., Anderson, R. C. and Bennett, G. F. (1956). Further observations on the transmission and development of Leucocytozoon simondi. Can. J . Zool. 34, 389404. Fallis, A. M., Jacobson, R. L. and Raybould, J. N. (1973). Haematozoa in domestic chickens and guinea fowl in Tanzania and transmission of Leucocytozoon neavei and L. schoutedeni.J. Protozool. 2 0 , 4 3 8 4 2 . Fantham, H. B. (1910a). On the occurrence of schizogony in an avian Leucocytozoon (L. lovati) parasitic in the red grouse, Lagopus scoticus. Ann. trop. Med. Parasit. 4, 255. Fantham, H. B. (1910b). Observations on the parasitic protozoa of the red grouse (Lagopus scoticus) with a note on the grouse fly. Proc. Zool. SOC.Lond. 692708. Fantham, H. B. (1921). Some parasitic protozoa found in South Africa. S. Afr. J. of Sci. 18, 164-170. Fantham, H. B. (1926). Some parasitic protozoa found in South Africa. IX. S. Afr. J. Sci. 23, 560-570. Fantham, H. B. (1927). Some parasitic protozoa found in South Africa. X. S. Afr. J. Sci. 24,441-449. Fantham, H. B., Porter, A. and Richardson, L. R. (1942). Some haematozoa observed in vertebrates in Eastern Canada. Parasitology 34, 199-226. Farmer, J. N. (1960). Some blood parasites from birds in central Iowa. Proc. Iowa Acad. Sci. 67, 591-597. Franqa, C. (1912a). Leucocytozoon du geai, de I’Cpervier et de la bCcasse. Bull. Sc.0 Path. exot. 5 , 17-21. Franqa, C. (1912b). Contribution al’Ctude des Leucocytozoon des oiseaux du Portugal. Bull. SOC.de la Path. exot. 5, 82-86. FranCa, C. (1 912c). Contribution a 1’Ctude des Leucocytozoondes oiseaux du Portugal. Bull. Soc. Path. exot. 5 , 173-176.

58

A. MURRAY FALLIS, SHERWIN

s.

DESSER A N D R A S U L A . K H A N

Franp, C . (1915). Quelques observations sur le genre Leucocytozoon. Bull. SOC. Path. exot. 8, 229-241. Franp, C. (1927). Notes parasitologiques. lorn. Sci. math. phys. nat. 5, 15-24. Franchini, G. (1923). Hematozoaires de quelques oiseaux d’Italie. Bull. SOC.Path. exot. 16, 118-125. Franchini, G. (1924). Observations sur les hkmatozoaires des oiseaux d’Italie. Annls Znst. Pasteur, Paris 38,470-515. Frank, W. (1965). Eine Leucocytozoon-Infektion bei Pennantsittichen (Platycercus elegans). Gejied. Welt 89, 193-194. Frank, W. (1967). Leucocytozoon-Infektion bei Nachzuchten australischer Sittiche in der deutschen Bundesrepublik. Bundesrepublik. IX. Znt. Symp. Erkrank. Zootiere Prague, 191-194. Frank, W. andKaiser, L. (1967).Infektionen mit Parasiten der GattungLeucocy tozoon (Protozoa, Sporozoa), bei Nachzuchten australischer Sittiche (Aves, Psittaciformes). 2. ParasitKde 28, 370-382. Galindo, P. and Sousa, 0. (1966). Blood parasites of birds from Almirante, Panama with ecological notes on the hosts. Revta Biol. 14,2746. Galli-Valerio, B. (1930). Notes de parasitologie. Zentbl. Bakt. ParasitKde Abt Z 115, 212-219. Gallucci, B. (1971). Fine structure of fertilization and ookinete formation in Haemoproteus columbae.J. Protozool. 18 (suppl.), 29. Gardiner, J. L. and Wehr, E. E. (1949). Some parasites of the wild turkey (Mefeagris gallopavo silvesrris) in Maryland. Proc. helminth. SOC.Washington 16, 16-1 9. Garnham, P. C. C. (1954). Distribution of blood protozoa in Africa. Proc. Linn. SOC. Lond. 165,61-66. Garnham, P. C. C. (1966). “Malaria parasites and other haemosporidia”. Blackwell, Oxford. Garnham, P. C . C., Bird, R. G., Baker, J. R. and Bray, R. S. (1961). Electron microscope studies of the motile stages of malaria parasites TI. The fine structure of the sporozoite of Laverania (=Plasmodium) falciparum. Trans. R . SOC.trop. Med. Hyg. 55,98-102. Garnham, P. C. C., Bird, R. G. and Baker, J. R. (1967). Electron microscope studies of the motile stages of malaria parasites. V. Exflagellation in Plasmodium, Hepatocystis, and Leucocytozoon. Trans. R. SOC.trop. Med. Hyg. 61,58-69. Garnham, P. C. C., Bird, R. G., Baker, J. R., Desser, S. S., El-Nahal, H.M.S. (1969). Electron microscope studies on motile stages of malaria parasites. VI. The ookinete of Plasmodium berghei yoelii and its transformation into the early oocyst. Trans. R. SOC.hop. Med. Hyg. 63, 187-194. Gaud, J. and Petitot, M. L. (1945). HCmatozoaires des oiseaux du Maroc. Archs Pasteur Maroc. 3, 149-171. Giovannola, A. (1 936). Les Leucocytozoon: leur developpement schizogonique. Annls Parasit. 14, 369-374. Glushchenko, V. V. (1962). [Material on the seasonal dynamics of blood parasites of birds in Kevak Polese]. Z . born. Prato Zool. Muz. Akad. Nauk. U.R.S.R. 31, 56-62. Goldsby, A. J. (1951). Poultry parasites new to North Dakota (Haemoproteus and Leucocytozoon).Bull. N. Dak. agric. Exp. Stn 13,121-122. Greiner, E. C. (1972). Parasites of Nebraska pheasants. J. Wildlge Dis. 8,203-206. Griffiths, R. B. (1964). Leucocytozoon caulleryi in the domestic fowl in Southeast Asia. Med. J. Malaysia 19,4041. Haberkorn, A. (1968). Zur hormonellen BeeinflussungvonHaemoproteusInfektionen. Z . Parasitenk. 31, 108-112.

O N SPECIES OF

LEUCOCYTOZOOW

59

Hanson, H. C., Levine, N. D., Kossack, C. W., Kantor, S. and Standard, L. J. (1957). Parasites of the mourning dove (Zenaidura macroura carolinensis) in Illinois. J. Parasit. 43, 186-193. Hart, J. W. (1949). Observations on blood parasites of birds in South Carolina. J. Parasit. 35, 79-82. Herman, C. M. (1938a). The relative incidence of blood protozoa in some birds from Cape Cod. Trans. Am. microsc. SOC.57, 132-141. Herman, C. M. (1938b). Leucocytozoon anatis Wickware, a synonym for L . simondi Mathis and Leger. J. Parasit. 24,472473. Herman, C. M. (1944). The blood protozoa of North American birds. Bird Banding 15,89-112. Herman, C. M. (1951). Blood parasites from California ducks and geese. J. Parasit. 37,280-282. Herman, C. M. (1968). Symp. Zool. SOC. London 24, 177-195. Herman, C. M., Barrow, J., Jr. and Tarshis, I. B. (1970). Epizootiology of Leucocytozoon in Canada geese (Branta canadensis). J. Parasit. 56, (11), 143. Hewitt, R. I. (1940). Studies on blood protozoa obtained from Mexican wild birds. Parasit. 26, 287-295. Hinshaw, W. R. and McNeil, E. ( I 943). Leucocytozoon sp. from turkeys in California. Poult. Sci. 22, 268-269. Hori, S., Toriumi, T. and Tanabe, A. (1964). Studies on the prevention of Leucocytozoort infection of the chicken. I. The behaviour of Culicoides arakawae to an insecticide DA-14-7. Scient. Rep. Fac. Agric. Okayama Univ. 24, 47-54. Hsu, C. K., Campbell, G. R. and Levine, N. D. ( I 973). A check list of the species of the genus Leucocytozoon (Apicomplexa, Plasmodiidae). J . Protozoof. 20, 195203. Huff, C. G. (1942). Schizogony and gametocyte development in Leucocytozoon simondi and comparisons with Plasmodium and Haemoproteus. J. infect. Dis. 71, 18-32. Huff, C. G. (1963). Experimental research on avian malaria. “Advances in Parasitology”, Vol. 1 (Ed. Ben Dawes), pp. 1-65. Academic Press, London and New York. Huff, C. G. (1968). Recent experimental research on avian malaria. “Advances in Parasitology”, Vol. 6 (Ed. Ben Dawes), 293-311. Academic Press, London and New York. Ivanic, M. (1937). Zur Kenntnis der gewohnlichen Zweiteilung und der in den Leberzellen der Hausgans (Anser domesticus L.) vorkommenden multiplen Teilung (schizogonie) bei Leucocytozoon anseris Knuths and Magdeburg. Arch. ParasitKde 89, 16-40. Jansen, B. C. (1952). The occurrence of some hitherto undescribed Leucocytozoon and Haemoproteus species in South African birds. Onderstepoort J. vet. Res. 25, 3-4. Johnson, E. P., Underhill, G. W., Cox, J. A. and Threlkeld, W. L. (1938). A blood protozoan of turkeys transmitted by Simulium nigroparvum (Twinn). Am. J . Hyg. 27, 648-665. Johnston, T. H. (1912). Internal parasites recorded from Australian birds. Emu 12, 105-1 12. Johnston, T. H. (191 6). A census of the endoparasites recorded as occurring in Queensland, arranged under their host. Proc. R . SOC.Qd 28.31-79. Jones, J. E., Barnett, B. D . and Solis, J. (1972). The effect of Leucocytozoon smithi infection on production, fertility and hatchability of broad breasted white turkey hens. Poultry Sci.51, 1573-1645.

60

A . M U R R A Y F A L L I S , S H E R W I N S. DESSER A N D R A S U L A . K H A N

Jordan, H. B. (1943).Blood protozoa of birds trapped in Athens, Georgia. J. Parasit. 29,260-263. Kerandel, J. (1909). Sur quelques hematozoaires observks a u Congo (Haute-SanghaLogone). Bull. SOC.Path. exot. 2,204-209. Kerandel, J. (191 3). Trypanosomes et Leucocytozoon observks chez des oiseaux du Congo. Annls Inst. Pasteur, Paris 27, 421-439. Keysselitz, G. and Mayer, M. (1909). Ueber ein Leucocytozoon bei einem Ostafrikanischen Perlhuhn (Guttera pucherani Hartl.). Arch. Protistenk. 54, 237-244. Khan, R. A. and Fallis, A. M. (1968).Comparisons of infections with Leucocytozoon simondi in black ducks (Anas rubripes), mallards (Anas platyrynchos) and white Pekins (Anus boschas). Can.J. Zool. 46,773-780. Khan, R. A. and Fallis, A. M. (1970a). Life cycles ofLeucocyrozoon dubreuili Mathis and LCger, 191 1 and L. fringillinarum Woodcock, 1910 (Haemosporidia; Leucocytozoidae). J. Protozool. 17,642-658. Khan, R. A. and Fallis, A. M. (1970b). Speciation, transmission and schizogony of Leucocytozoon in corvid birds. Can. J. Zool. 49,1363-1367. Khan, R. A. and Fallis, A. M. (1970~).Relapses in birds infected with species of Leucocytozoon. Can. J. Zool. 48,451-455. Khan, R. A.,Desser,S. S a n d Fallis,A. M. (1969). Survivalofsporozoites ofleucocytozoon in birds for 11 days. Can. J.Zool. 47,347-350. Kitaoka, S., Morii, T. and Kosoge, M. (1965). Field experiments on the repellents to chicken biting midges. Jup. J. sanir. Zool. 16,244-248. Kitaoka, S., Morii, T. and Fujisaki, K. (1972). Quantitative observations on schizogony of Akiba caulleryi of chickens. Nut. Inst. Anirn. Hlth Q . 12, 151-160. Klei, T. R. (1972). The fine structure of Huemoproteus columbae sporozoites. J. Protozool. 19,281-286. Knuth, P. (1922).Demonstration uber in Deutschland gefundene Leukozytozoen der Hausgans. Arch. Schifls-u. Tropenhyg. 26, 315-3 17. Knuth, P. and Magdeburg, F. (1922). Ueber ein durch Leukozytozoen verursachtes Sterben junger Ganse. Berl. tierarztl. Wschr. 38, 359-361. Knuth, P. and Magdeburg, F. (1924). Uber Leucocytozoen bei der Hausgans. Z . InfektKrankh. 26,42-52. Kocan, R. M. (1968). Anemia and mechanism af erythrocyte destruction in ducks with acute Leucocytozoon infections. J. Protozool. 15,445-462. Kocan, R. M. and Clark, D. T. (1 966). Anemia in ducks infected with Leucocytozoon simondi. J. Protozool. 13,465-468. Kozicky, E. L. (1948).Some protozoan parasites of the eastern wild turkey in Pennsylvania. J . Wildl. Mgmt 12, 263-266. Kuppusarny, A. R. (1936). Leucocytozoa and nlicrofilaria of fowls and Haemoproteus columbae of pigeons in province Wellesley. Indian vet. J. 13,2635. Lainson, R. and Shaw, J. J. (1969).A new haemosporidian of lizards. Saurocytozoon tupinambi gen. nov., sp. nov., in Tupinamubs nigropunctatus (Teiidae). Parasitology 59, 159-162. Lainson, R., Shaw, J. J. and Humphrey, P. S. (1970). Preliminary survey of blood parasites of birds of the area de Pesquisas ecologicas do Guama, BelCm, Par& Brad. J. Parasit. 56, sect. II., 197-198. Laird, M. (1950). Some blood parasites of New Zealand birds. Zool. Publ. Victoria University College No. 5, 1-20. Laird, M. (1961). A lack of avian and mammalian haematozoa in the Antarctic and Canadian Arctic. Can. J. Zool. 39, 209-213. Laird, M. and Bennett, G. F. (1970). The subarctic epizootiology of Leucocytozoon simondi. J. Parasit. 56 (IT), 199.

O N S P E C I E S OF L E U C O C Y T O Z O O N

61

Landau,I.andChabaud, A. G. (1968).Schizogoniehepatiquesecondairedanslapaludisme spontane des rongeurs. C. r. hebd. Skanc. Acad. Sci.,ParisD266,1730-1733. LaPage, G. (1961). A list of the parasitic protozoa, helminths and Arthropoda recorded from species of the family Anatidae (ducks, geese, and swans). Parasitology 51, 1-109. Laveran, M. A. (1902). Sur une Haemamoeba d’une mesange (Parus major). C . r. Skanc SOC.Biol.51, 1121-1124. Laveran, M. A. (1903). Contribution h E t u d e de Haemamoeba ziemanni. C. r. Skanc. SOC.Biol. 55, 620-623. Laveran, M. A. and Lucet, A. (1905). Deux hematozoaires de la perdix et du dindon. C . r. hebd. Skanc. Acad. Sci., Paris 141,673-676. Laveran, A. and Murullaz, M. (1914). Sur des Hemamibes et un Toxoplasma du Liothrix luteus. Bull. SOC.Path. exot. 7,21-25. Laveran, A. and Nattan-Larrier, L. (191 1). Sur un Leucocyfozoon de I’aigle Haliaefus vocifer. C. r. Skanc. SOC.Biol.70,686-688. Lee, Y. C., Chang, C. H., Hsu, T. R. and Yeh, L. C. (l966a). Studies on the leucocytozoonosis of chickens. I. Study of chemical control with various drugs. Mem. Coll. Agr. natn. Taiwan Univ. 8, 169-174. Lee, Y. C., Chang, C. H., Hsu, C. K. and Yeh, L. C. (1966b). Studies on the Leucocytozoonosis of chickens. Part 11. Development of preventative methods with some chemical drugs. J. agric. Ass. China 54,70-76. Lee, Y . C., Chang, C. H. and Fuh, T. H. (1969). Studies on Leucocytozoonosis of chickens. VI. On the natural immunity to L. caulleryi. J. Taiwan Ass. Anim. Husb. vet. Med. 14, 9-15. Uger, M. (1913). Hematozoaires d‘oiseaux de la Corse. Bid/. SOC.Path. exot. 6, 51 5-523. LCger, M. (191 7). Observations sur quelques Leucocytozoon doiseaux de la region de Reims. Bull. SOC.Path. exot. 10,28-33. LCger, A. and Blanchard, M. (191 1). Hematozoaires d‘un passereau du Haut.-Senegal et Niger (Hyphantornis melanocephala Linne). Bull. SOC.Path. exot. 4, 526-527. Leger, A. and Lkger, M. (1914). Les Leucocytozoon: leur denombrement et essai de classification. Bull. SOC.Path. exot. 7,437-447. Leger, M. and Mathis, C. (1909). Leucocytozoon de la perdix du Tonkin. Annls Znst. Pasteur. 23, 740-743. Levine, N. D . (1954). Leucocytozoon in the avian order Columbiformes with a description of L. marchouxi Mathis and Leger, 1910 from the mourning dove. J. Protozool. 1, 140-143. Levine, N. D. (1962). Geographic host distribution of blood parasites in columbroid birds. Trans. Ill. St. Acad. Sci. 5592-1 1 1 . Levine, N. D. (1973). “Protozoan parasites of domestic animals and man”. Burgess, Minneapolis. Levine, N. D. and Hanson, H. C. (1953). Blood parasites of the Canada goose Branta canadensis interior. J. Wild. Mgmt 17, 185-196. Levine, N. D. and Kantor, S. (1959).Check list of blood parasites of birds of the order Columbiformes. Wild. Dis. 1, 1-38. Love, G. L., Wilkin, S.A. and Goodwin, M. H. (1953). Incidence of blood parasites in birds collected in south-west Georgia. J. Parasit. 39,52-57. Lubinsky, G., Levite, M. and Grinchpone, C. (1940). De la faune des hematozoaires chez les fringillides des environs de Kiev. [Tr. from Russian]. Parazit. Sb. 8, 9 1-99. Mackerras, M. J. and Mackerras, I. M. ( I 960). The haematozoa of Australian birds. Austr. J. Zool. 8, 226-260.

62

A . M U R R A Y F A L L I S , SHERWIN S . DESSER A N D R A S U L A . K H A N

Maegraith, B. (1968). Liver involvement in acute mammalian malaria with special reference to Plasmodium knowlesi malaria. “Advances in Parasitology”, Vol. 6 E d . Ben Dawes). Academic Press, London. Manuel, M. F. (1969). Further studies on Leucocytozoon caulleryi in domestic fowls in the Philippines. Avian Dis. 13,280-287. Manwell, R. D. (1951). Leucocytozoon and other blood parasites of the purple grackle Quiscalusquiscala quiscalu. J. Parasit. 37, 301-306. Manwell, R. M. (1955). Relative incidence of blood parasites in robins of central New York and of the high rockies. J.Protozool. 2,85-88. Manwell, R. D. and Herman, C. M. (1935). Blood parasites of birds of the Syracuse (N.Y.) region. Anat. Rec. 60 (suppl.), 78. Martin, R. K. (1932). The cytology of Leucocytozoon anutis Wickware. J. Parasit. 19, 179. Mathis, C. and Leger, M. (1909a). Leucocytozoonde la poule. C. r. Skanc. SOC.Biol. 67, 470472. Mathis, C. and LCger, M. (1909b). RCcherches sur le Leucocytozoon de la poule. PCriodicitC des formes sexuhs dans le sang. C. r. SPanc. SOC.Biol. 67,688-690. Mathis, C. and Uger, M. (1910a). Parasites sanguicoles d‘un passereau du Tonkin (Zxus hitianus) boulboul de l’isle d’Hainan. C. r. Sdanc. SOC.Biol. 69, 30-32. Mathis, C. and Uger, A. (1910b). Nouvelles rkherches sur Leucocytozoon sabrazesi et Leucocytozoon caulleryi de la poule domestique du Tonkin. Bull. SOC.Path. exot. 3,504-510. Mathis, C. and Uger, M. (1910~).Leucocytozoon d‘une tourtelle (Turtur humilis) et d‘une sarcelle (Querquedulacrecca) du Tonkin. C. r. SPanc. SOC.Biol. 68, 118120. Mathis, C. and LCger, M. (1911a). Leucocytozoon d‘un Paon d‘un Crabier et d’un Bengali du Tonkin. C. r. Sdanc. SOC.Biol. 70,211-212. Mathis, C. and LCger, M. (1911b). “RCcherches de parasitologie et de pathologie humaines et animales au Tonkin”. Masson et Cie, Paris, Mathis, C. and Gger, M. (1912). Nature des cellules-h6tes des Leucocytozoon. Bull. SOC.Path. exot. 5,77-82. Mello, I. F. de (1935). A contribution to the study of the blood parasites of some Indian birds. Proc. Indian Acad. Sci. 1B, 349-358. Mello, I.F. de(1937a).OnHaemoprotozoaofIndian birds. C. r. 12 Cong. International Zool. Lisbon 2, 1391-1 445. Mello, I. F. de (1937b). Further contributions to the study of the blood parasites of the Indian birds, together with a list of haemoparasites not hitherto recorded. JI R . Asiat. SOC.Beng. (Science) 2,95-122. Mello, I. F. de and Alfonse, E. (1935). Blood parasites of Coracias b. benghalensis with special remarks on its two types of Leucocytozoon.Proc. Indian Acad. Sci. I1 B, 67-73. Mine, M. (1914). Beitrage zur Kenntnis der Blutparasiten der Vogel in Japan. Arch. Purasitenk. 34, 198-21 1. Mohammed, A. H. H. (1958). “Systematic and Experimental studies on Protozoal Blood Parasites of Egyptian Birds”. Cairo University Press. Moldovan,J. (1913). Beitrag zur Entwicklung das Leucocytozoonziemanni (Laveran). Zentbl. Bakt. ParasitKde 71, 66-69. Morgan, B. B. and Waller, E. F. (1941). Some parasites of the eastern crow (Corvus brachyrhynchos brachyrhynchos Brehm). Bird Banding 12, 16-22. Morii, T. (1972). Presence of antigens and antibodies in the sera of chickens infected with Akiba caulleryi. Natn. Inst. Anirn. With Q., Tokyo 12, 161-167.

O N SPECIES O F

LEUCOCYTOZOON

63

Morii, T. and Kitaoka, S. (1968a). Susceptibility of chickens of different ages to sporozoites of Akiba caulleryi at various doses. Natn. Znst. Anim. Hlth Q., Tokyo 9, 104-111. Morii, T. and Kitaoka, S. (1968b). Influence of temperature on the sporogony of Akiba caulleryi in three Culicoides species. Natn. Znst. Anim. Hlth Q., Tokyo 8, 210-216. Morii, T. and Kitaoka, S. (1969). Susceptibility of chickens to sporozoites of Akiba caulleryi. Natn. Znst. Anim. Hlth Q., Tokyo 9, 104-1 11. Morii, T. and Kitaoka, S. (1970). Some aspects on immunity to Akiba caulleryi infections in chickens. Natn. Znst. Anim. Hlth Q., Tokyo 8, 204-209. Morii, T. and Kitaoka, S. (1971). Susceptibility of the gallinaceous birds to Akiba caulleryi. Natn. Znst. Anim. Hlth Q., Tokyo 11, 170-171. Morii, T., Kitaoka, S. and Akiba, K. (1965). Some investigations on the sporogony of Leucocytozoon caulleryi in laboratory reared biting midges of four Culicoides species. Natn. Znst. Anim. Hlth Q., Tokyo 5 , 109-110. Nelson, E. C. and Gashwilder, J. S. (1941). Blood parasites of some Maine waterfowl J. Wildl. Mgmt 5, 199-205. Newberne. J. W. (1955). The pathology of Leucocytozoon infection in turkeys with a note on its tissue stages. Am. J. vet. Res. 16, 593-597. Newberne, J. W. (1957). Studies on the histopathology of Leucocytozoon simondi infection. Am. J. vet. Res. 18, 191-199. Newman, M. W. (1968). Protozoan parasites of ruffed and Franklin's grouse in Alberta. M.Sc. Thesis, University of Alberta, Edmonton, Canada. Newman, M. W. (1970). Large schizonts of Leucocytozoon from the kidney of the ruffed grouse (Bonasa urnbellus). Can. J. Zool. 48, 879-880. Nikitin, S. A. and Artemenko, V. D. (1927) [Veberdie Protozoa des Blutes Dei WirbeltierenderSudlichenUkraine]. In Russian. Russk.Zh. trop. Med.5,654-664. Noblet,R., Adkins,T. R.andKissam, J. B. (1972). Simulium congareenarum (Diptera: Simuliidae) a new vector of Leucocytozoon smithi (Sporozoa: Leucocytozoidea) in domestic turkeys. J. med. Ent. 9,580. Ogawa, M. (1912). Notizen uber die blutparasitischen Protozoen bei japanischen Vogeln. Arch. Protistenk. 24, 119. Oliger, I. M. (1940). Parasitic protozoa and their role in the fluctuation of the Hazel Grouse (Tetrastes bonasia L.) population in the northern part of the Gorkij province. Dokl. Akad. Nauk. SSSR 28,470-473. Omar, A. R. (1968). Haemoprotozoan infections of poultry in Malaysia. Kajian Vet. 1, 109-124. O'Meara, D. C. (1956). Blood parasites of some Maine waterfowl. J. Wildl.Mgmt 20, 207-209. Oosthuizen, J. H. and Markus, M. B. (1967a). The haematozoa of South African birds. I. Blood and other parasites of two species of game birds. Ibis 109,115-1 17. Oosthuizen, J. H. and Markus, M. B. (1967b). The haematozoa of South African birds. 11. Blood parasites of some Rhodesian birds. J. S. Afr. vet. med. Ass. 38, 438-440. Oosthuizen, J. H. and Markus, M. B. (1967~).Blood parasites of birds. Bokmakierie 19, 20-21. Oosthuizen, J. H. and Markus, M. B. (1968). The haematozoa of South African birds. IV. Leucocytozoonosis in nestlings. J. Parasit. 54, 1244-1246. O'Roke, E. C. (1930). The incidence, pathogenicityand transmission of Leucocytozoon anatis of ducks. J. Parasit. 17, 112. ORoke, E. C. (1931). The life history of Leucocytozoon anatis Wickware. J. Parasit. 18, 127.

64

A . M U R R A Y F A L L I S , S H E R W I N S . DESSER A N D R A S U L A . K H A N

O’Roke, E. C. (1934). A malaria-like disease of ducks. Univ. Mich. Sch. For. Conserv. Bull. 4, 44. Pan, I. C. (1963). A new interpretation of the gametogony of Leucocytozoon caulleryi in chickens. Avian Dis. 7, 361-368. Peters, J. L. (1931-1970). Checklist of birds of the world, 1-13. Museum of Comparative Zoology, Cambridge, Mass. Plimmer, H. G. (1913). Report on thedeaths whichoccurredin theZoological Gardens during 1912 together with a list of the blood parasites found during the year. Proc. Zool. SOC.Lond. 141-149. Plimmer, H. G. (1914). Report on the deaths which occurred in the Zoological Gardens during 1913, together with a list of the blood parasites found during the year. Proc. Zool. SOC.Lond. 181-190. Porchet-Hennere, E. and Richards, A. (1 969). Structure fine du sporoblaste immature uninuclee d’Aggregatu eberthi Lab% (Sporozoaire: Coccidiomorphe). C. Y. hebd. Sganc. Acud. Sci., Paris 269, 1681-1683. Porchet-Hennere, E. and Richards, A. (1971). La sporogenese chez la coccidie Aggregutu eherthi. etude en microscope electronique. J. Protozool. 18, 614616. Porchet-Hennerk, E. and Vivier, E. (1 971). Observations sur le “crystalloide” des coccidies. J. Protozool. 18, 51. Prowazek, S. von (1912). Beitrage zur Kenntnis der Protozoen und verwandter Organismen von Sumatra (Deli). Arch. Protistenk. 26, 250-274. Ramisz, A. (1962). Protozoa of the genus Leucocytozoon Danilewski, 1890 in birds in the environs of Wroclaw. Actaparasit. pol. 10, 39-53. Rawley, J. ( 1 953). Observations on the maturation of gametocytes of Leucocyfozoon 20, 127-128. simondi. Proc. helminth. SOC. Renjifo, S., Sanmartin, C. and De Zulueta, J. (1952). A survey of the blood parasites of vertebrates in Eastern Columbia. Actu trop. 9, 151-169. Richey, D. J. and Ware, A. E. (1955). Schizonts of Leucocytozoon smithi in artificially infected turkeys. Cornell Vet. 45, 642-643. Roberts, W. L., Mahrt, J. L. and Hammond, D. M. (1972). The fine structure of sporozoites of Isosporu canis. Z. PurasitKde 40,183-194. Rodhain, J. (1931). Deux Leucocytozoon d’oiseaux du Congo Belge. C. r. Sianc. SOC. Biol. 107,273-276. Rodhain, J., Pons, C., Vandenbranden, F. and Bequaert, J. (191 3). Notes sur quelques hematozoaires du Congo belge. Arch. Protistenk. 29, 259-278. Roller, N. F. and Desser,,S. S. (1973a). Diurnal periodicity in peripheral parasitemias in ducklings (Anas boschas) infected with Leucocytozoonsimondi Mathis & LCger. Can.J. Zool. 51, 1-9. Roller, N. F. and Desser, S. S. (1973b). The effect of temperature, ageand density of gametocytes and changes in gas composition on exflagellation of Leucocytozoon simondi. Can. J. Zool. 51, 577-587. Roslien, D. J. and Haugen, A. 0. (1970). Blood parasites found in some Iowa game birds. J. Parusit. 56, sect. 11, 291. Rousselot, R. (1953). “Notes de Parasitologie Tropicale Tome. I. Parasites du Sang des Animaux”. Vigot Freres, Paris. Sachs, I. B. (1953). Certain blood-inhabiting protozoa of birds in the vicinity of Urbana, Illinois. Trans. Am. miscrosc. SOC.72,216-227. Sadun, E. H. (1949). Leucocytozoon simondi infection in domestic ducks in northern Michigan with a note on Haemoproteus. Poultry Science 28, 870-893. Sakharoff, M. N. (1893). Rkcherches sur les hematozoaires des oiseaux. Annls Inst. Pasteur, Paris 7, 801-81 1.

O N SPECIES O F

LEUCOCYTOZOON

65

Sambon, L. W. (1908). Remarks on the avian haemoprotozoa of the genus Leucocytozoon, Danilewsky. J. trop. Med. Hyg. 11,325-328. Savage, A. and Isa, J. M. (1945). An outbreak of Leucocytozoon disease in turkeys. Cornell Vet. 35,270-272. Savage, A. and Isa, J. M. (1959). A note on Leucocytozoon disease in ducks. Cornell Vet. 49, 252-254. Schaudinn, F. (1904). Generations- und Wirtswichsel bei Trypanosoma und Spirochaete. Arb. K . GesundhAmt. 20,387-439. Scholtyseck, E., Melhorn, H. and Friedhoff, K. (1970).The fine structure of theconoid of Sporozoa and related organisms. Z . ParasitKde 34,68-94. Scott, H. H. (1926). Report on the deaths occurring in the Society’s Gardens during the year 1925. Proc. zool. SOC.Lond., 231-244. Seligman, C. G. and Sambon, L. W. (1907). Preliminary note on Leucocytozoon found in the blood of the red grouse (Lagopus scoticus). Lancet 2,829-830. Seneviratna, P. and Bandaranayake, A. (1 963). Leucocytozoon caulleryi Mathis & LCger, 1909 infection in domestic fowl in Ceylon. Ceylon vet. J. 11, 2-8. Sergent, E. and Fabiani, G. (I 922). Sur un Leucocytozoon d’un rapace diurne d’Algerie (Circaetiis gallicus) (Gmel.). Archs. Inst. Pasteur Afrique Nord. 2, 480. Sergent, E. and Sergent, E. (1905). Observations sur les hematozoaires des oiseaux d‘Algerie. Nouvelle hemamibe de I’hirondelle. C. r. SPanc. Soc. Biol. 58,56-57. Sergent, E. andSergent, E. (1907).Etudesstir les hematozoaires d‘oiseaux(P1asmodium relictum, Leucocytozoon ziemanni, Haemoproteus noctuae, H . columbae, trypanosome de I’hirondelle Algerie, 1906). Annls Inst. Pasteur, Paris 21, 251-280. Sewell, R. B. S. (1938).“The Fauna of British India”. Taylor and Francis, London. Simpson, C. F., Anthony, D. W. and Young, F. (1956). Parasitism of adult Turkeys in Florida by Leucocytozoon smithi (Laveran and Lucet). J. Am. vet. med. Ass. 129, 573-576. Sivadas, C. A., Noir, M. K., Rajan, A. and Ramachandran, K. M. (1965).A disease in poultry resembling “Bangkok haemorrhagic disease of chickens”. Indian vet. J. 42, 816-823. Skidmore, L. V. ( 1 93 1). Leuococytozoonsmithiinfectionin turkeys and its transmission by Simulium occidentale Townsend. J. Parasit. 18, 130. Skidmore, L. V. (1932).Leucocytozoon smithi infection in turkeys and its transmission by Simirlium occidentale Townsend. Zentbl. Bakt. ParasitKde Abt. I125,329-335. Smith, Th. (1895). Investigations concerning infectious diseases among poultry. Bull. No. 8, Bureau of Animal Industry, Washington. Son, C. K. (1960). The occurrence of some Leucocytozoon and Haemoproteus species in guinea fowl, chicken and pigeon of Mozambique. Annls Inst. Med. trop. 17, 765-785. Stabler, R. M. (1961). A parasitological survey of fifty-one eastern white-winged doves. J. Parasit. 47, 309-3 1 1. Stabler, R. M. and Holt, P. A. (1963). Haematozoa from Colorado birds. I. Pigeon and doves. J. Parasit. 49, 320-322. Stephan, J. (1922). Uber eine durch LeukocytozoenverursachteGanse-und-Putenerkrankung. Dt. tierarzl. Wschr. 30, 589-592. Sterling, C. R. (1972). Ultrastructural study of gametocytes and gametogenesis of Haemoproteus metchnikovi. J. Protozool. 19, 69-76. Sterling, C. R. and Aikawa, M. (1973). A comparative study of gametocyte ultrastructure in avian Haemosporidia. J. Protozool. 20, 8 1-92. Sterling, C. R. and DeGuisti, D. (1974). The fine structure of differentiating oocysts and mature sporozoites of Haemoproteus metchnikovi. J. Protozool. 21, 276283.

66

A . MURRAY FALLIS, S H E R W I N

s.

DESSER AND RASUL A. K H A N

Stoddart, E. D., Tumlin, J. T. and Cooperrider, D. E. (1952). Recent outbreak of Leucocytozoon infection in adult turkeys in Georgia. J. Am. vet. med. Ass. 121, 190-195. Takos, M. (1947).Blood parasites of some Panamanian birds. J. Parasit. 33,229-330. Tarshis, I. B. (1972). The feeding of some ornithophilic black flies (Diptera: Simuliidae) in the laboratory and their role in the transmission of Leucocytozoon simondi. Ann. ent. SOC.Am. 65,842-848. Tendeiro, J. (1947).Acerca dos hematozoarios de algumas aves da Guine Portuguesa. Revta Med. vet. 42,285-346. Terzakis, J. A. (1969). A protozoan virus. Milit. Med. 134,916-921. Terzakis, J. A. (1971). Transformation of the Plasmodium cynomolgi oocyst. J. Protozool. 18,62-73. Tenakis, J. A., Sprinz, H. and Ward, R. A. (1966).Sporoblast and sporozoite formation in Plasmodium gallinaceum infection of Aedes aegypti. Milit. Med. 131, 984992. Tenakis, J. A., Sprinz, H. and Ward, R. A. (1967).The transformation of the Plasmodiumgallinaceumoocysts in Aedes aegyptimosquitoes. J. CeIlBiol.34,311-326. Thompson, P.E.(1943).The relative incidence of blood parasites in some birds from Georgia. J. Parasit. 29, 153-155. Todd, J. L.and Wolbach, S.B. (1912).Parasitic protozoa from the Gambia. J. med. Res. 26, 195-218. Trainer, D. O.,Schildt, G. S.,Hunt, R. A. and John, L. R. (1962). Prevalence of Leucocytozoon simondi among some Wisconsin waterfowl. J. WiIdI. Mgmt 26, 137-143. Travis, B. V., Goodwin, J. M. H. and Gambrell, E. (1939).Preliminary note on the occurrence of Leucocytozoon smithi Laveran and Lucet (1905) in turkeys in southeastern United States. J. Parasit. 25,278. Trefiak, W. D. T. and Desser, S. S. (1973). A comparative study of the crystalloid inclusions in Leucocytozoon, Plasmodium and Parahaemoproteus. J. Protozool. 20, 73-80. Uegaki, J. (1930). Untersuchungen uber die Blutprotozoen von Vogeln der Siidsee. Arch. Protistenk. 72,7490. Van den Berghe, L. (1942). Parasites du sang du vertebrb. Exploration du Parc National Albert et du Parc National de la Kagera 1, 1-1 5. Vanderberg, J., Rhodin, J. and Yoeli, M. (1967). Electron microscope and histochemical studies of sporozoite formation in Plasmodium berghei. J. Protozool. 14, 82-103. Volkmar, F. (1929). Observations on Leucocytozoon smithi with notes on Leucocytozoon in other poultry. J. Parasit. 16,2428. Walker, J. (1912).uber ein Leucocytozoonbeim Vogel. Z . Znfektionskrankh.Haustiere 12, 372-375. Walker, J. (1913).A short note on the presence of a Leucocytozoon infection. Host: the ostrich. Trans.R . SOC.S. Africa 3,35-38. Walker, D. and Garnham, P. C. C. (1972). Aberrant Leucocytozoon infections in Parakeets. Vet. Rec. July 15, 70-72. Wehr, F. (1962).Studies on Leucocytozoonosis of turkeys with notes on schizogony, transmission and control of Leucocytozoon smithi. Avian Dis. 6, 195-210. Wenyon, C. M. (1908). Report of the travelling pathologist and protozoologist. Third Report Wellcome Res. Labs. Khartoum 121-168, 157-165. Wenyon, C. M. (1926). “Protozoology”. Bailliere, Tindall and Cox, London. West, J. R. and Starr, L. E. (1940). Further observations on a blood protozoan infection in turkeys. Vet.Med. 35,649-653.

ON SPECIES OF L E U C O C Y T O Z O O N

67

Wetmore, P. W. (1941). Blood parasites of birds of the District of Columbia and Patuxent Research Refuge vicinity. J. Parasit. 27,379-393. Wickware, A. B. (1915). Is Leucocytozoon anatis the cause of a new disease in ducks? Parasitology 8,17-21. Wingstrand, K. G. (1947). On some haematozoa of Swedish birds with remarks on the schizogony of Leucocytozoon sakharofi. Kungl. Svenska Vetenskapsakad. Handl. 24, 1-3 1. Wingstrand, K. G. (1948). Further studies on Leucocytozoon sakharofi Kungl. Svenska Vetenskapsakad.Handl. 24, 1-17. Wood, F. D. and Wood, S. F. (1937). Occurrence of haematozoa in some California birds and mammals. J. Parasit. 23, 197-202. Wood, S. and Herman, C. M. (1943). The occurrence of blood parasites in birds from southwestern United States. J. Parasit. 29, 187-196. Woodcock, H. M. 0910). Studies on avian Haemoprotozoa. I. On certain parasites of the chaffinch (Fringilla coelebs) and the red poll (Linota rufescens). Q. J. microsc. Sci. 55, 641-740. Wohnus, J. F. and Ryerson, D. L. (1941). HeIpatozoa from California birds. J. Parasit. 27, 540-541. Yang, Y.J. (1971). In vitro cultivation of exoerthrocytic stages of Leucocytozoon simondi. Can. J. Zool. 49, 561-563. Yang, Y. J., Desser, S. S. and Fallis, A. M. (1971). Elongate and round gametocytes of Leucocytozoon simondi Mathis & Lkger in ducks inoculated with megaloschizonts. J. Protozool. 18, 553-556. Zajicek, D. (1968). Trypanosoma dafilae sp. n. and Leucocytozoon anatis Wickware 1915 in the northern pintail (Dafilaacuta acuta L.). FoliaParasit. 15,169-172. Ziemann, H. (1898). ‘‘uber Malaria und andere Blutparasiten”. Fischer, Jena. ADDENDUM

The following relevant papers have appeared since the manuscript was prepared: Siccardi, F. J., Rutherford, H. 0. and Derieux, W. T. (1974). Pathology and prevention of Leucocytozoon smithi infection of turkeys. Avian Dis. 18,21-32. Solis, J. (1973). Nonsusceptibility of some avian species to turkey Leucocytozoon infection. Poultry Sci. 52, 498-500.

This Page Intentionally Left Blank

Recent Advances in Antimalarial Chemotherapy and Drug Resistance WALLACE PETERS

Department of Parasitology. Liverpool School of Tropical Medicine. Liverpool. England I . Introduction .................................................................................... I1. Newer Techniques for Drug Testing ...................................................... I11. Mode of Action of Antimalarial Drugs ................................................... A Chloroquine and Related Compounds ............................................. B. Tissue Schizontocides and Sporontocides .......................................... C. Pigment Clumping as an Investigative Tool ......:................................ D . Drugs Acting on Pathways of Folate Metabolism .............................. IV. Drug-Parasite-Host Interactions ......................................................... V. Mechanisms of Drug Resistance ............................................................ A . Patterns of Cross-Resistance ......................................................... B . Resistance to Chloroquine and Related Compounds ........................... C. Resistance to Primaquine and Other Tissue Schizontocides .................. D. Resistance to Dihydrofolate Reductase Inhibitors .............................. E. Transmission of Drug-Resistant Strains of Plasmodium ........................ VI New Antimalarial Drugs and Drug Combinations .................................... A Quinoline and Phenanthrenemethanok, Quinine Analogues .................. B . New Dihydrofolate Reductase Inhibitors .......................................... C. Sulphonamides and Sulphones......................................................... D. Antibiotics ................................................................................. E . Interesting Miscellaneous Compounds ............................................. F. Drug Combinations ..................................................................... VII Tomorrow’s Outlook ........................................................................... References .......................................................................................

69 71 15 15 78 82 84 89 89 89 94 95 96 91 91 91 98 99

.

.

.

.

102 103 104 105 106

I. INTRODUCTION Many readers will be surprised to learn that. after so many years of intensive campaigns designed to eradicate malaria. the following authoritative statement appears in a current publication of the World Health Organisation (1973):

..... the provision of effective chemoprophylaxis and adequate treatment of malaria is still one of the major problems in tropical countries ..... The greater part of all research on the treatment of malaria has been undertaken during this century; like so many facets of scientific research the tempo this has followed has been exponential . During the past decade there has been 69

70

W A L L A C E PETERS

a greater concentration of research effort related to the field of malaria chemotherapy than in the entire first half of the century. A few years ago I attempted to review the major part of the information available up to that time in order to make some kind of sense out of the wealth of data that had been accumuleted concerning, in particular, the way antimalarial drugs work, and the way in which malaria parasites become resistant to them (Peters, 1970a).In retrospect, it is clear that, as I was reminded by a scholarly paper by Sadun (1972), my bibliographical studies should have gone yet further back into the recesses of history. However, modern technology being as it is, I believe that we may gain more by analysing and sieving the torrent of current information than by seeking clues in the remote past. While we must certainly learn by past lessons, we must also be prepared to look critically at our present and our future, and that is what I attempt to do in these pages. Several valuable reviews have appeared on the topic of antimalarial chemotherapy in recent years. Particular attention is drawn to two reports of WHO Scientific Groups (1967; 1973), to the monographs of Pinder (1971), Steck (1971) and Thompson and Werbel (1972), and to briefer, more selected reviews by Elslager (1969), Schmidt (1969), Peters (1969), Newton (1970), Richards (1970), Howells et al. (1972) and Warhurst (1973). The recent report of WHO (1973) reiterates the roles that drugs play in both the control and eradication of malaria in endemic areas, whereas the increasing problem of imported malaria (into both endemic and non-endemic countries) is stressed by Bruce-Chwatt (1970a, 1973). This author has also given a remarkably concise review of the role that malaria and antimalarials have played in military operations from earliest times up to the present day (Bruce-Chwatt, 1971). Just how serious the resistance of malaria parasites to antimalarial drugs is in practical terms depends upon one’s point of view. The only species of parasite of importance to man that has developed resistance of a significant degree is Plasmodium falciparum which, in several geographical areas, is highly resistant to chloroquine (Fig. 1) and to dihydrofolate reductase inhibitors (antifols). It is against these strains that most of the chemotherapy research of the past decade has been directed. More than one quarter of a million compounds have been screened for antimalarial action in vivo during this period in the course of the U.S. Army chemotherapy research programme alone, and this does not include an unknown number that have been investigated by other organizations including universities and pharmaceutical laboratories. Chloroquine resistance in P.fakiparum is spreading faster than malaria control or eradication can keep up with the transmission of this parasite. It is today threatening parts of South-East Asia, and in particular the Indian sub-continent, where the efforts of the last 20 years that nearly achieved the the interruption of malaria transmission are, for one reason or another, beginning to break down. What would happen, for example, if falciparum malaria broke out in epidemic fashion in India where the greater part of the population are now non-immune, as happened recently with vivax malaria in Sri Lanka (formerly Ceylon)? Resistant strains have been identified already as far West as Rangoon in Burma (Clyde et al., 1972)and as far East as Sabah (Clyde et al., 1973a)and the Philippines (Shute e l al., 1970; Ramos el al., 1971). Fortunately

-8

ANTIMALARIAL CHEMOTHERAPY A N D D R U G RESISTANCE

0

o inn

71

Uganda I ,Kenva (Kiwmu)

c

.-

5 2 !i

(Motto Grosso)\

\Brazil

c

5 0 Chloroquine n m l /ml of blood I

0

I

I

I

I

160

320

480

640

Chioropuine pg

I

800

I

1

960 1120 base I 1000mL of Blood

I 1280

I

I

1440

1600

FIG.1. Chloroquine sensitivity of P. faleiparum in vitro and in vivo. The figures show the responses obtained in 3 sensitive African strains of P . faleiparum compared with strains of varying levels of resistance from West Malaysia, Brazil and South Vietnam. (Reproduced with permission from WHO, 1973 and Dr K. H. Rieckmann). (Copyright WHO, Geneva).

chloroquine resistance is still unproven on the African continent (BruceChwatt, 1970b; WHO, 1973). It seems possible that a genetic susceptibility may play a role (Hall and Canfield, 1972).

TECHNIQUES FOR DRUG TESTING 11. NEWER For those concerned with the screening of drugs for antimalarial action the recent WHO publication (1973) gives a very useful guide that covers the entire topic from primary screening to the monitoring of a new drug during mass drug administration in the field. While this document contains no radically new techniques, it does provide a most valuable orientation on the relative merits of current standard procedures. For example, more weight is given to the direct evaluation of a compound against the malaria parasites of man, either in vitro or in simian hosts, than in previous publications including that of Peters (1970a). In primary screening in vivo, attention is drawn to the use by Fink and Kretschmar (1970) of P. vinckei as an alternative to P . berghei which has, by now, become the classical model for this purpose. While rodent malaria provides a satisfactory model for the demonstration of blood schizontocidal action, it has proved less satisfactory in relation to causal prophylacticactivity, and attention is turning once again to avian Plasmodium models. While Fink et al. (1970) favour P. cathemerium in the canary, Gerberg (197 1) and Gerberg and Kutz (1971) adhere to the classical P. gallinaceum-chickmodel, as do Rane and Rane (1972). The latter have attempted to adapt their highly successful mass techniques used for screening of blood schizontocides in the P. bergheimouse system (Osdene et al., 1967, expanded in Peters, 1970a) to combined

72

WALLACE PETERS

FIG.2. The South American owl monkey (Aotus trivirgatus).These animals weigh up to about 1200 g when fully grown. (Photograph by courtesy of Mr D. G. Taylor, Nuffield Institute of Comparative Medicine).

screening for blood and tissue schizontocidal action, using the same basic criterion of survival time. The availability of a number of drug-resistant strains of P . falcipariim in the South American owl monkey (Aotus trivirgatus) (Fig. 2) has provided us with an opportunity of making a direct assessment of a drug’s action against these organisms by employing a modification of the invaluable in vitro technique devised by Rieckmann et al. (1968) (see Table I). An alternative technique involvin&la “rocker dilution” procedure has been proposed by Siddiqui et al. (1972). Direct studies of tissue schizontocidal action can also be made on avian parasites in tissue culture, but this method requires further development. The

ANTIMALARIAL CHEMOTHERAPY A N D D R U G RESISTANCE

73

adaptation of human malaria parasites to the owl monkey has provided us with an unprecedentedly valuable model for the tertiary evaluation of the more promising compounds that are selected by primary screening and that survive secondary evaluation (e.g. toxicity testing). This subject has been reviewed by Schmidt (1969, 1973) who has pioneered the field. Procedures have been defined both for the examination of drugs for blood schizontocidal effect against drug-sensitive and drug-resistant P. falciparum and P . vivax, and for tissue schizontocidal action against the latter. However, the simian parasite P . cynomolgi in the rhesus monkey still provides a. most practical model for vivax malaria, and antifol resistant strains of this parasite are widely used. Baseline data on the resDonse of various strains of P. falcbarum and P . vivax in Aotus trivirgatus to various standard drugs are nowavaiable (WHO, 1973; Schmidt, 1973). Various techniques have been devised for experiments designed to investigate the mode of action of antimalarials, and their pharmacological properties. Pharmacological studies have been made from two points of view, firstly to determine the pharmacodynamic aspects of their antimalarial action and

TABLE I Responses of infections with various strains of Plasmodium falciparum and Plasmodium vivax in Aotus trivirgatus to chIoroquine, pyrimethamine andquinine. (Reproduced with permission from Schmidt, 1973)

Curative dose-mg base/kg body weight administered once daily for 7 days ~~~

Strain

Chloroquine

~~

~~

Pyrimethamine

Quinine

Plasmodiumfalciparum ~

Uganda Palo Alto Malayan Camp (Sadun) Malayan Camp-CH/Q Cambodian I Malayan IV Vietnam Monterey Vietnam Oak Knoll Vietnam Smith Honduras Palo Alton

5.0 5.0 > 5 . 0 ; < 10.0 5.0

>2.5

>2x20.0

>2.5 >2.5 > 2.5 >2.5 1.0 ca. 0.15

>20.0

>2.5

20.0 > 2 x 20.0 2.5

~~~

~

20.0 20.0 >20.0; 80.0

0.025

10.0

0.625

40.0 40.0

PIasmodium vivax

New Guinea Chesson Vietnam Palo Alto

2.5 2-5

Evaluated in the splenectomizedowl monkey. (Copyright Trans. R . SOC.trop. Med. Hyg.). @

>2.5

74

W A L L A C E PETERS

toxicity, i.e. how the drugs are handled by the host, and secondly, how they interact with the parasite-host cell complex. Classical pharmacological techniques have been applied, for example, to determining the metabolic fate of diformyl dapsone (DFD) (e.g. Gordon et al., 1970; Chiou, 1971; Gleason and Vogh, 1971) and sulphonamides. Contrary to expectations, genetic variation in the rate of acetylation of dapsone by leprosy patients plays no role in their therapeutic response to this compound (Ellard et al., 1972). However, pharmacogenetic factors may be important in relation to “sulphonamid; resistance” in malaria infection (Clyde et al., 1971~).In general, in vitro methods have yielded more useful data on the molecular pharmacology of the antimalarials at the level of the parasite-host cell complex. Study of the direct interaction of drugs with parasite and host enzymes has given a valuable insight into the mode of action of compounds such as pyrimethamine that inhibit folate metabolism (e.g. Ferone, 1970; Gutteridge and Trigg, 1971) and chloroquine (Gutteridge et al., 1972). The reviving and extension of old techniques for short-term in vitro culture of malaria parasites has enabled workers such as Trager (1971) and Siddiqui et al. (1972) to study new drugs, e.g. pantothenate antagonists or drug combinations (McCormick et al., 1971; McCormick and Canfield, 1972). Schnell and Siddiqui (1972) have used cultures both of P.fakiparum and P.knowlesi to study the action of antibiotics on protein synthesis; they have also investigated the influence of various amino acids in the culture medium on the growth of these parasites (Siddiqui and Schnell, 1972). Cultivation techniques’in general were reviewed recently by WHO (Bertagna et al., 1972). The rodent parasite P. berghei has been most frequently employed for short-term culture. Cenedella et al. (1970), Van Dyke et al. (1970b), Richards and Williams (1971,1973), and Williams and Richards (1973) have reported new methods for screening, the latter being based on the uptake of 3H-leucine in leucocyte-free P. berghei-infected rat blood. These techniques also lend themselves to some degree to a study of the mode of drug action (Carter el al., 1972; Carter and Van Dyke, 1972). Other protista such as Tetrahymenapyriformis which is readily cultured in vitro have yielded useful information in the hands of Chou and Ramanathan (1968) studying mepacrine, Conklin el al. (1969,1970)quinine, and Conklin and Chou (1972) primaquine, although their data must be translated with caution in relation to antiplasmodial action because of the vast differences in physiology and biochemistry of these two groups bf protozoa. Studies with various bacteria have continued to yield valuable data especially on drug resistance, e.g. Siege1 et al. (1970). A most useful approach to the study of the action of drugs in the intact malaria parasite is that of Warhurst and his associates which is based on the well-known phenomenon of the clumping of haemozoin by the exposure of intraerythrocytic malaria parasites to chloroquine. Warhurst et al. (1971) have shown that parasite protein synthesis is essential for this process to occur in vivo and in vitro (Warhurst and Baggaley, 1972). This technique is currently proving of value not only in studying the modes of action of new drugs (Warhurst et al., 1972)but also in probing the intimate details of parasite respiration (Homewood et al., 1972c) (see Section IIIc).

A N T I M A L A R I A L C H E M O T H E R A P Y A N D D R U G RESISTANCE

75

111. MODEOF ACTION OF ANTIMALARIAL DRUGS A.

CHLOROQUINE AND RELATED COMPOUNDS

1. Concentration of drugs in parasitized erythrocytes While it has long been recognized that chloroquine (l), amodiaquine (2) and mepacrine (3) are concentrated in plasmodium-parasitized erythrocytes (see

1. chloroquirn

2. amodiaauine

3. mepacrine

review by Peters, 1970a) the mechanism by which this occurs has until recently remained obscure. Homewood and Warhurst (1971) have proposed a simple physico-chemical explanation for this phenomenon. They suggest (Homewood et al., 1972b) that compounds such as these possess just the right combination of lipid solubility and ability to become doubly protonated to permit them to pass from the serum into the trophozoite phagosomes which are normally maintained at an acid pH (this is required for optimum functioning of the parasites’ proteolytic enzymes). This hypothesis fits well with observations of other workers such as Fitch (1969, 1970) and Polet (1970) both of whom have observed a very rapid initial, energy-independent, uptake of chloroquine by drug-sensitive parasites. Kramer and Matusik (1971) have suggested that the high affinity binding sites are associated with parasite membranes. Fitch (1972) and Warhurst (1973) have attempted to define the nature of these sites. The former made direct measurements of the binding properties of a variety of anti-malarials and related these to other physico-chemical properties of the drugs, but was unable to define the site completely by this means. Warhurst (1973), using the indirect approach described by Warhurst et al. (1972) postulated that the site must be lipophilic, and associated with two special groups. One is an electron-acceptor hydrogen-bonding group, and this is separated by 3 4 A from a negatively charged, ionized acidic gioup. Several workers have attempted to forecast structure activity relationships among various chemical classes of antimalarials by sophisticated analytical approaches beyond the scope of this review (e.g. Hudson et al., 1970; Cheng, 1971; Craig, 1972). 2. Influence on parasite feeding mechanisms Within the phagosomes the entry of basic chloroquine ions must lead to a depletion of acid radicles with the result that the pH increases, probably beyond the optimum range for the enzymes that are normally responsible fof the proteolysis of the host haemoglobin, taken into the phagosome via the cytostome. The net outcome of this is an acute amino acid deprivation, or, in

76

WALLACE PETERS

short, the parasite starves. Chloroquine may well have secondary effects on the phagosome membranes. By analogy with the well recognized effects in mammalian lysosomes (which may also underlie the recently recognized syndrome of chloroquine myopathy (Hughes et al., 1971)), it is possible that the membranes, initially stabilized to some degree, become labilized with higher drug concentrations, thus permitting leakage of the phagosome contents into the general endoplasm of the parasite, but this is probably a subterminal phenomenon. Conklin and Chou’s (I 970) observation that in Tetrahymena pyriformis chloroquinine, mepacrine, quinine and primaquine block amino acid uptake may have some relevance in thiscontext. Working with P. lophurae Sherman and Tanigoshi (1972) concluded that the inhibitory effects of chloroquine, quinine and primaquine on amino acid incorporation were due to the influence of the drugs on the energetics of the parasites. and not a direct block of amino acid uptake. 3. Morphological effects The clumping of the individual haemozoin granules of developing trophozoites that rapidly follows exposure to chloroquine or mepacrine has been well documented in earlier reviews and does not need further emphasis here. It is, however, the detailed analysis of this phenomenon by Warhurst and his colleagues that has led to most recent advances in our understanding of the mode of action of these drugs (see Section IIIc). Warhurst and Baggaley (1972) have devised a simple in vitro technique for the quantitative evaluation of haemozoin clumping. The nature of haemozoin is still in dispute. Homewood et al. (1972a) suggest that the parasite may actually synthesize it from haemin, and that it is not simply a degradation product of haemoglobin. 4. Biochemical effects

The biochemistry and .metabolism of the malaria parasite have recently been reviewed in a useful paper by Fletcher and Maegraith (1972) that forms a background to the following paragraphs. Most studies on the biochemical effects of chloroquine’s action on malaria parasites have been focused on nucleic acid metabolism ever since the demonstration some years ago that the drug intercalates with DNA (see review by Newton, 1970). Gutteridge et al. (1972) have shown that DNA extracted from P . knowlesi also binds chloroquine. They havC, in addition, like Van Dyke et al. (1969), shown that chloroquine inhibits the uptake of 3H-adenosine by trophozoites in short-term culture (Van Dyke et al., 1970b, have made this action the basis of a screening technique for antimalarial drugs). Theakston et al. (1972) have confirmed this in vivo and shown that methionine uptake is also reduced. Blodgett and Yielding (1968) and subsequently Morris et al. (1970) have demonstrated that chloroquine binds not only to DNA but also to various polynucleotides although the latter emphasize that these in vitro studies can only give a pointer to the mode of action of a drug in a biological system. Histones interfere with DNA-chloroquine binding (Washington et al., 1973). Certainly in the intact organism chloroquine causes a breakdown in the

ANTIMALARIAL CHEMOTHERAPY A N D D R U G RESISTANCE

77

larger species of ribosomal RNA but Warhurst and Williamson (1 970) believe that this is a consequence of autolysis inside the cytolysosome that is formed within the parasite on exposure to the drug. They believe that any gross intercalation with parasite DNA is likely to follow only when the internal organization of the drug-exposed parasites has been completely disrupted and free drug is released within the general parasite substance. A similar phenomenon has been reported by Hendy et al. (1969) in rat heart lysosomes while Filkins (1969) has shown that this compound labilizes rat liver lysosomes, causing increased lysosomal enzyme activity. It is interesting in this context that Whichard and Holbrook (1970) found that the formation of a chloroquineRNA complex renders the RNA more sensitive to hydrolysis by ribonuclease. Van Dyke el al. (1970a) have shown that mepacrine too inhibits adenosine uptake by P . berghei. In addition it blocks the incorporation of ATP into RNA. More recently, following a careful analysis of the energetics of P. berghei (Carter et al., 1972) and particularly the role of cyclic AMP, Carter and Van Dyke (1972) have attempted to define whether the effects of antimalarials on purine incorporation in cell-free parasites are due to inhibition of uptake, phosphorylation or polymerization. They concluded that mepacrine and quinine inhibit the last two functions at low concentrations, whereas chloroquine and primaquine do not. In other protozoa mepacrine exerts different effects: Chou and Ramanathan (1968), for example, find that it inhibits synchronized cell division in Tetrahymena pyriformis, possibly by inhibiting DNA synthesis through interference with the cells’ energy production. It is interesting to note that in Crithidia fasciculata O’Connell et al. (1 968) found that the inhibition of growth caused by exposure to mepacrine was reversed by certain Krebs cycle intermediates and the amino acid products could be derived from them by transamination. The mode of action of quinine (20) appears to be more complex than that of chloroquine or mepacrine (see also Section IIIc). Like mepacrine it appears to influence the energy-generating mechanism of T . pyriformis (Conklin et al., 1969) and its effects on DNA synthesis and protein synthesis may be secondary to this as in P . lophurae (Sherman and Tanigoshi, 1972). Certainly it inhibits DNA-dependent DNA polymerase in vitro and Estensen et al. (1969) suggest that this may be associated with the binding of quinine to more than one class of DNA binding site. Rat liver microsomal enzyme activity is inhibited by quinine (Boulos et al., 1970) with a subsequent decrease in the rate of breakdown of substances that are normally metabolized with the aid of these enzymes. Cambar and Aviado (1970) have drawn attention to an interesting pharmacological action of a 4-aminoquinoline with chloroquine-like antimalarial activity, WR 4809. The hypotensive action of this compound is said to be due to blockade of both 01 and P-adrenetgic receptors in mammalian muscle but they do not suggest that this bears any relation to the drug’s antimalarial activity. A curious interrelationship of chloroquine and the iron intake of host red cells was noted by Siu (1972) who found that the drug increased uptake of this metal. Mice pretreated with iron and then infected with P . berghei responded

78

W A L L A C E PETERS

better to chloroquine than animals on a low iron diet. The reason for this is at present obscure. B.

TISSUE SCHIZONTOCIDES AND SPORONTOCIDES

1. Metabolic studies Fundamental to an understanding of the differential mode of action of antimalarial drugs in the different stages of the life cycle is a knowledge of the changes that the metabolism of the parasite undergoes as it moves from vertebrate to invertebrate and back. In earlier sections of this review are summarized the ways in which drugs such as chloroquine enter the parasite and intervene in its mechanism for obtaining amino acids. Clearly this can only apply to stages that actively engulf haemoglobin and break it down by proteolytic enzymes that require an acid pH. This is not the case with the mature gametocytes, the sporogonic stages or the exo-erythrocytic schizonts. Howells (1970) and Howells and Bafort (1970) have shown that the rodent parasite P . berghei undergoes a cyclic change in its respiratory pathways as it passes between the vertebrate and invertebrate stages of the life cycle (see reviews by Peters, 1970c and Howells et al., 1972). Probably commencing with the macrogametocyte, the parasites develop cristate mitchondria and it is likely that they begin producing enzymes of the Krebs citric acid cycle (Fig. 3). This cycle appears to be fully functional in the sporogonic stages but once the sporozoites enter liver parenchymal cells the pathway is “switched off” and the pre-erythrocytic schizont has been shown to be devoid of typical enzymes of the Krebs cycle such as succinic dehydrogenase. Howells and Maxwell (1973a) have shown that P . berghei-infected reticulocytes contain a single isoenzyme of NAD- and of NADP-dependent isocitrate dehydrogenase (IDH). On the other hand, a different isoenzyme of each can be demonstrated in infected A . stephensi midguts, distinguishable both from those of mouse blood and of the mosquito. Scheibel and Pflaum (1970) doubt whether the cytochrome oxidase of P . knowdesi functions in the asexual erythrocytic stages. The mitochondria-associated enzymes of rodent parasites, at least, thus appear to be of major importance in the invertebrate but not the vertebrate stages. 2. Morphological effects Although certain sulphonamides and dihydrofolate reductase inhibitors such as pyrimethamine probably function as tissue schizontocides and sporontocides, these will be dealt with in a later section and the present discussion will be restricted to drugs with other modes of action, particularly the 8-aminoquinolines and naphthoquinones. Beaudoin and Aikawa (1968) showed that primaquine (4)induces morphologicalchanges in the exo-erythrocytic schizonts of P.,fallu.xin tissue culture. They have been able to show that tritiated primaquine is taken up rapidly by the mitochondrial membranes and only after a long delay comes to be associated also with the paired organelles (Aikawa and Beaudoin, 1970). Although Howells et al. (1970a) have been able to demonstrate ultrastructural changes in the whorled organelles(probab1y mitochondrial

A N T I M A L A R I A L C H E M O T H E R A P Y A N D D R U G RESISTANCE

MOSQUITO

79

MOUSE

‘. \

Spaoroik \ \ \

Oocysk

/

/ /

I’

/’

Ookinetc

?

/ / / /

FIG.3. Diagrammatic representation of the changes observed within the mitochondria of P. berghei during the course of the parasites’ life cycle. The presence of stippling or hatching within the mitochondria indicates that the enzymes’ activity has been demonstrated for the mitochondria at that stage of development. Cyt. oxidase =cytochrome oxidase S.D.H. = succinate dehydrogenase NADP-IDH =nicotinamide adenine triphosphate-dependent isocitrate dehydrogenase NAD-IDH =nicotinamide adenine diphosphate-dependent IDH P.E. schuont = pre-erythrocytic schizont Chlor. =chloroquine mat. and imm. =mature and immature (Reproduced with permission from Howells and Maxwell, 1973a). (Copyright Ann. trop. Med. Parasit.).

equivalents) of the asexual erythrocytic stages of P . berghei, following exposure to primaquine in vivo, they have not been able to do so in the sporogonic stages (Davies et al., 1971). They postulate that this may be due to the necessity for primaquine and related compounds (5, 6, 7) to be metabolized to an active derivative in vivo, similar to (S), in the mouse whereas, in their experiments on the sporogonic stages, the parasites were exposed directly to primaquine in sugar solutions fed to Anopheles stephensi. This makes even more puzzling the claim ofTerzian (1970) that primaquine interferes with the maturing sporozoites but not the earlier oocyst stages.

80

WALLACE PETERS

4. primaquine

7. pamaquine

6. quinocide

5. pentaquine

8. 5:6 quinoline-quinone derivative

3. Biochemical effects The haemolytic effects of primaquine are well known and their relation to G-6-PD deficiency has been well documented. There has been a number of reports of clinical trials to determine the extent to which primaquine causes haemolysis in normal or enzyme-deficient subjects when given in association with other drugs. Pannacciulli et a/. (1969) found that weekly doses of 45 mg primaquine with 300 mg chloroquine base caused no haemolysis in G-6-PD deficient negroes but did do so in a high proportion of Caucasians with the deficiency, e.g. Sardinians. Primaquine sensitivity is frequent too in Laotian males (12.4 % of 89 examined by Ebisawa and Muto, 1972).Clyde et al. (1970b) found that the potential haemolytic action of the weekly chloroquine-primaquine combination was enhanced when, in addition, 25 mg of dapsone was given daily or 200 mg of diformyldapsone (DFD) weekly. This toxicity was not manifested however in enzyme-normal subjects. When exposed to a low concentration of primaquine, normal erythrocytes were shown by Ginn et al. (1969) to develop changes in the ultrastructure of the membrane and vacuolization that the authors suggest is related to the haemolytic effect. A direct inhibiting effect of a variety of antimalarials on isolated G-6-PD in vitro has been demonstrated by Cotton and Sutorius (1971) but at high concentrations. Lantz and Van Dyke (1970) have shown that primaquine and pamaquine inhibit the uptake of tritiated ATP into the RNA of cell-free preparations of P. berghei. They suggest that this may be due either to blockade of the template function of DNA or inhibition of the RNA polymerase. However, as the concentrations that they found effective were relatively high, Carter and Van Dyke (1972) concluded that these weE not important in vivo. Morris et al. (1970) have found that several 8-aminoquinolines bind to polyribonucleotides in vitro. While suggesting from their experiments that these compounds probably affect several functions of RNA as well as nucleic acid synthesis, they emphasized the danger of too literal a translation of their findings to the biological mechanisms of the intact organism. The same caution should be applied in inter-

A N T I M A L A R I A L CHEMOTHERAPY A N D D R U G RESISTANCE

81

preting the observations of Whichard et al. (1972) who showed that 8-aminoquinolines and two hydroxylated derivatives inhibit certain bacterial DNA polymerases. The presence of DNA-associated histones decreases the degree of binding of 8-aminoquinolines to isolated DNA (Washington et al., 1973). In Tetrahymena pyriformis Conklin and Chou (1970) found that primaquine appears to block the uptake of amino acids but here the same precaution may apply in relating these observations to Plasmodium. It will be recalled that Skelton et al. (1968) showed that in P . lophurae several antimalarials including primaquine affect enzyme systems involving mitochondria and the biosynthesis of ubiquinones. This group has now shown that a number of mammalian species, P . knowlesi, P . cynomolgi and P . berghei synthesize ubiquinone-8 (Skelton et al., 1970). In rat liver mitochondrial preparations Howland (1965) showed that a number of naphthoquinones inhibit the respiratory chain between cytochromes b and c1 and that this action could be reversed by ubiquinone. Both menoctone (a naphthoquinone derivative) (26) and primaquine have been shown to cause mitochondrial damage in the exoerythrocytic stages of P . fallax (Aikawa and Beaudoin, 1969) and P . berghei (Berberian and Slighter, 1968). Howells et al. (1970a) found that menoctone produced similar changes to primaquine in the morphology of the asexual erythrocytic stages of P . berghei while Peters (1970e) noted that there was an additive effect when these two drugs were given together. However he also found that, while menoctone potentiated the action of cycloguanil, primaquine produced no clear potentiation. He therefore questioned whether primaquine and menoctone do in fact exert their effects at the same site. Sherman and Tanigoshi (1972) have emphasized the importance of drug action (including that of primaquine) on the energetics of P . lophurue rather than on specificmetabolic functions such as amino-acid uptake. Recently Dunn et al. (1972) have shown that P . berghei pre-erythrocytic schizonts failed to grow in ethionine-treated rats but the effect is largely reversed by administering methionine or adenosine. The basic effect may be due to deprivation of labile methyl groups. As Warhurst (1973) has pointed out, considerably more needs to be known about the modes of action of tissue schizontocides.

4.Newly reported tissue schizontocides and sporontocides A sulphamethoxazole-trimethoprim combination appeared not to have a gametocytocidal action against P . fakiparum (Wilkinson et ul., 1973) but McCarthy and Clyde (1973) have shown clearly that another sulphonamide, sulfalene (13), is gametocytocidal if given when young gametocytes are in the course of development. The tissue schizontocidal effect of the pyrocatechol compound RC12 (30) has once again been reported, this time by Sodeman etal. (1972) but no indication is given of its mode of action. RC 12 also has a sporontocidal action against P . cynomolgi bastianellii (Omar and Collins, 1973). In a series of experiments on the pre-erythrocytic schizogony of P . cynomolgi ceylonensis and P . vivax,Garnham et al. (1971) made the incidental observation that oxytetracycline has a tissue schizontocidal action. This observation is now being

82

W A L L A C E PETERS

followed up in man by various investigators including Rieckmann et al. (1971a) and Clyde et al. (1971a). Several lincomycin derivatives were shown by Schmidt et al. (1970)to havean incomplete action as causal prophylactics and secondary tissue schizontocides against P . cynomolgi. C.

PIGMENT CLUMPING AS AN INVESTIGATIVE TOOL

1. Parasite metabolism Intrigued by the rapidity with which haemozoin clumps in the presence of a low concentration of chloroquine (Fig. 4), Warhurst set out to investigate the factors concerned in the formation of the cytolysome, or autophagic vacuole so formed which contains, in addition to the granules of haemozoin, a variety of other, normal cytoplasmicconstituents such as ribosomes. Warhurst and Robinson (1971) found that in vivo a variety of cytotoxic agents that are known either to inhibit nucleic acid synthesis (e.g. actinomycin D, earlier shown by Fink End Goldenberg, 1969, to exert a schizontocidal action on P . berghei) or protein synthesis (e.g. the antibiotic tetracycline, also a recognized schizontocide), failed to produce clumping of haemozoin in P . berghei. On the other hand, when such drugs were used to pretreat parasites which were subsequently exposed to chloroquine, even non-schizontocidal concentrations of such ribosomal protein synthesis inhibitors as cycloheximide caused a marked inhibition of the chloroquine-induced pigment clumping. Inhibitors of RNA synthesis produced only a limited effect (Warhurst et al., 1971) in vivo. This phenomenon has now been observed in a simple in vitro system by Warhurst and Baggaley (1972), so confirming the contention that protein synthesis is essential for autophagic vacuole formation as well as some degree of RNA synthesis. These authors, moreover, found that clumping was inhibited by rotenone, a respiratory inhibitor. Chloroquine alone inhibits clumping only when a very high concentration is used, probably because of inhibition of

Time from exposure to chloroquine (min)

FIG.4. The effect of chloroquine on the haemozoin of P . berghei N strain in vifro. Note the decrease in fine pigment within 10 min of exposure to the drug (in a concentration of 1 0 - f i ~ ) and a corresponding increase in granular and clumped pigment. Nearly all pigment is clumped within 60-80 min. (Original figure by courtesy of Dr D. C. Warhurst.)

ANTIMALARIAL CHEMOTHERAPY AND DRUG RESISTANCE

83

nucleic acid synthesis (Warhurst et al., 1972), although at the lower concentrations corresponding to those achieved in practice chloroquine itself inhibits neither nucleic acid nor protein synthesis (Homewood et al., 1971). Homewood and her colleagues (1 972c) are now investigating the respiratory metabolism of P . berglwi using chloroquine-induced pigment clumping as a tool to study the physiology of the intact parasite within the host erythrocyte. In preliminary experiments they confirmed that, unlike the initial stages, the later phase of chloroquine uptake by the parasites is glucose dependent, as originally pointed out by Polet (1970). By using inhibitors such ‘as rotenone cyanide and antimycin A that block different parts of the electron transport chain, and measuring both oxygen uptake and chloroquine-induced pigment clumping, they have revealed that P . berghei contains a previously unrecognized type of electron transport chain that can function in the absence of oxygen (Homewood et al., 1972~).This opens a whole field of investigation into protozoal respiratory mechanisms. Recently, for example, it has been shown that cystine and methionine are the only amino acids required in the medium used for these in vitro clumping experiments (Homewood and Atkinson, 1973). 2. Mode of drug action As Warhurst and Baggaley (1972) have pointed out, on the basis of their influence on chloroquine-induced clumping or their own ability to cause clumping, antimalarial agents can be divided into at least four categories, i.e. (1) 4-aminoquinolines and mepacrine (2) 8-aminoquinolines (3) Cinchona alkaloids (4) Antimetabolites such as pyrimethamine and sulphadiazine. Warhurst et a / . (1972) have now extended these observations to a wider range of drugs including recently developed phenanthrenemethanols and quinolinemethanols. The latter two groups (which are known, like quinine, to retain schizontocidal action against a number of chloroquine-resistant strains of P . fakiparum), are now shown to have a quinine-like effect, apparently competing with chloroquine for the binding sites of the latter in the parasites. They have shown that drugs which induce autophagic vacuole formation on their own apparently bind to the clumping site as does quinine but, in addition, have the ability to become doubly protonated at physiological pH. Their general arguments on structure-activity relationships agree well with those proposed by Bass et al. (1971) on the basis of their complex analysis of physicochemical data on a wide range of 4-aminoquinoline antimalarials. Even drugs with no antimalarial action but with the appropriate sidechains and partition coefficients, e.g. dichloroisoproterenol, can show a quinine-like activity. The sidechain structure is vital and, for example, 4-7,-dichloroquinoline, is ineffective(WarhurstandMallory, 1973). The presence of a “3 A dipole” is a common physicochemical property of several antimalarials which otherwise appear quite different, e.g. mepacrine, febrifugine, BW 377C54 (Warhurst and Thomas, 1973). The suggestion of various authors that chloroquine acts primarily by intercalating with parasite DNA can no longer be considered tenable in the light of more recent studies such as those reviewed above, and of

84

W A L L A C E PETERS

Gutteridge et al. (1972) who showed that chloroquine has a similar affinity for the DNA o f f . knodesiand its host. Moreover, the physicochemical analyses of Angerman el a/. (1972) give further contrary evidence. D.

DRUGS ACTING ON PATHWAYS OF FOLATE METABOLISM

I . Sulphonamides and sulphones With the revival of interest in the antimalarial action of sulphonamides and sulphones and the synthesis of new derivatives of these groups, attention has been turned to their basic pharrnacodynamics. A comprehensive review of the relationship between pharmacokinetics of sulphonamides and the therapeutic regimen was given by Kriiger-Thiemer and Biinger (1965-66). Marked species differences are known in the metabolic disposition of sulphonamides and this is well brought out in a study on various primate species including man, dogs and rodents by Adamson el al. (1970), working with sulphadimethoxine. More attention is being given at present to sulphones and in particular to dapsone (9) itself and its diformyl analogue (DFD) (10). While DFD appears to be a good suppressive drug in clinical trials in volunteers reported by Clyde et a/. (1970c, 1971d) and Willerson et al. (1972b), these authors emphasize the need for more long-term studies on the compound's tolerability, both alone and combined with other antimalarials. A new test has been devised for the assay of dapsone and proguanil in urine when the two drugs are given together. This test, described by Kreutzmann (1970) is based on U.V.examination of a thin-layer chromatograph. Species differences in the metabolism of dapsone and genetically determined differences within species are reviewed by Hucker (1970) who points out that man is a relatively slow acetylator of this drug (as distinct, for example, from the rhesus), and similar observations are reported by Gordon et a/. (1970). If dapsone is administered together with probenecid its urinary excretion is delayed (Goodwin and Sparell, 1969). This does not, however, seem to offer any practical advantage since the diformyl derivative in any case has a much longer half-life in man. Aviado e t a / . (1968) found that DFD was less toxic than dapsone while producing similar blood levels and questioned whether the antimalarial action of DFD was really referable to the deformylated metabolite or DFD itself. It is interesting to note that rodents deformylate DFD more rapidly with plasma than with liver enzymes (Gleason and Vogh, 1971), while the reverse is true for man (Chiou, 1971). When given together with chloroquine to dogs in subacute toxicity tests DFD appears to have no influence on the rate of accumulation of chloroquine in the tissues of the eye (Lee et af.,1971). There appears to be little more recent knowledge on the mode of action at the molecular level of sulphonamides and sulphones against malaria parasites. Cenedella and Jarrell(l970) have found that dapsone interferes with transport of glucose at the level of the erythrocyte membrane and that the drug is concentrated there. The drug's antimalarial action is moreover partially reversed by induced hyperglycaemia (Cenedella and Saxe, 1971). Sulphadiazine does not have this action on glucose transport. They suggest that this may be one of the ways in which dapsone inhibits the growth of intra-erythrocytic P .

ANTIMALARIAL CHEMOTHERAPY A N D DRUG RESISTANCE

RHN a S 0 2 e N H R '

HzN e S 0 2 N H R '

10. DFD

1 1 . acedapsone

g

R5

R: 9. dapsone

85

-H

12. sulfadoxine

129, 131, 142, 152, 175 Pfeiffer, H., 282, 326, 327, 357, 363 Maum, W. K., 78, 112 Phifer, K., 237, 245, 267 Phillips, A. A., 382, 389 Phillips, S. F., 209, 225, 262, 264, 268, 274 Picq, J.-J., 92, 108 Pinder, R. M., 70, I 1 I Platzer, E. G., 88, Ill, 226, 270 Plaut, A. G . , 219, 268 Playfair, J. H. L., 89, 109 Playoust, M. R., 223, 247, 257 Pleasants, J. R., 228, 269 Plimmer, H. G., 3, 64 Plotkin, G . R., 211, 212, 235, 236, 268 Podesta, R. B., 186, 191, 210, 211, 212, 213, 214, 215, 216, 218, 219, 222, 228, 236, 237, 244, 245, 246, 248, 268

Poelvoorde, J., 321, 357 Polet, H., 75, 83, 94, 95, 111 Pons, C., 2, 3, 7, 9, 17, 64 Pope, J. L., 225, 268 Popkin, J. S., 208, 258 Porchet-Hennere, E., 47, 64 Porter, A., 3, 57 Porter, D. A., 283, 287, 329, 334, 343, 352,357 Porter, M., 90, 111 Portman, R., 222, 258 Portus, J., 90, 91, 92, 93, 94, 95, 111 Powell, D. W., 211, 212, 235, 236, 247, 250, 268 Powell, E. C., 121, 136, 142, 148, 149, 178, 180 Powell, R. D., 72, 82, 91, 100, 102, 111 Powers, K. G., 89, 90, 92, 102, 111 Pradhan, S. L., 305, 357 Prata, A., 375, 384, 385 Pratt, I., 329, 343 Preshaw, R. M., 220, 268 Prince, H. N., 88, 109 Pritchard, R. K., 211, 268 Prizont, R., 247, 268 Proctor, B. G . , 306, 318,358 Prosper, J., 228, 268 Prowazek, S . von, 9, 17, 64 Purcell, W. P., 75, 83, 106, 109 Purdy, S . , 240, 273

Q Quick, J . D,, 219, 268 Quigley, J. P., 231, 268 Quinn, T. C., 81, 108 R Race, G. J., 117, 125, 129, 180 Radke, M. G . , 370,388 Raison, C. G., 372, 387 Raizes, G. S . , 301, 302, 359 Rajan, A., 48, 65 Ralph, R., 184, 277 Ramachandran, K. M., 48, 65 Ramalho-Pinto, F. J., 142, 143, 151, 152, 163, 164, 167, 168, 173, 174, 177, 178, 180 Ramanathan, S., 74, 77, 107, 108 Rambourg, A., 125, 180 Ramisz, A., 3, 19, 31, 64 Ramkaran, A. E., 90, 94, 97, 111

AUTHOR INDEX

Ramos, 0. L., 70,111 Ranatunga, P., 334, 358 Rane, D. S.,71, 111 Rane, L., 71, 110, 111 Ransom, B. H., 330,358 Rawes, D. A., 320,357 Rawley, J., 26, 64 Ray, A. P., 70, 112 Raybould, J. N., 17, 26, 27, 28, 33, 34, 57 Raynaud, J. P., 292, 358 Rayski, C., 313, 314, 317,351,356,365 Read, C. P., 186,194,195,197,200,202, 203, 208, 214, 222, 226, 228, 229, 230, 231,236,240,242,243,244,245,249, 252, 256, 267, 268,269, 270 Rebert, C. C., 80, 84, 90,107 Rector, F. C., 189, 191, 209, 235, 245, 248,256 Rector, F. C., Jr., 211, 212, 236, 275 Reddy, B. S.,228, 269 Redfield, A. X., 212, 264 Rees, P. H., 376, 388 Rees, R. J. W., 74, 108 Rees, R. W. A., 99, 111 Refuerzo, P. G., 334, 358 Reichenbach-Klinke, H. H., 222, 269 Reichenbach-Klinke, K. E., 222,269 Reid, J. F. S.,286, 293, 299, 358 Reid, W. M., 220, 269 Reiser, S.,242, 269 Reisin, I., 235, 252 Reissig, M., 118, 180 Reitemeier, R., 186, 272 Renjifo, S., 3, 64 Repetto, Y.,211, 249 Reynolds, E. S., 118, 119, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 133, 139, 144, 146, 148, 169, 181 Rhodes, M. D., 222, 269 Rhodin, J., 46, 66 Ricciardi, M. L., 104, 108 Rice, J., 244, 264 Richard, J., 131, 132, 180, 181 Richard, L., 90, 113 Richards, A., 47,64 Richards, H. C., 369, 378, 379, 384,388 Richards, W. H. G., 70, 74, 105, 106, Ill, 113 Richardson, L. R., 3, 57 Richey, D. J., 25, 64 Ricosse, J.-H., 92, 108

409

Rider, A. K., 244,269 Riecken, E. O., 248, 269 Rieckmann, K. H., 72, 82, 84,85,90,91, 92, 99, 100, 102, 111, 113 Rietz, P. J., 81, 112 Rifkin, E., 123, 124, 125, 126, 127, 129, 142, 152,181 Ritchie, J. S. D., 288, 292, 297,344,358 Ritchie, L. S.,370, 388 Roberts, F. H. S.,303, 311, 329, 336,358 Roberts, J. M. D., 376, 388 Roberts, L. S., 200, 222, 226, 228, 240, 264,269, 270 Roberts, W. L., 47, 64 Robinson, B. L., 74, 82, 90, 91, 92, 93, 94, 95, 102, 111, 113 Robinson, C. S.,212, 251 Robinson, J. W. L., 243, 270 Robson, R. T., 117, 118, 119, 125, 126, 128, 129, 130, 131, 136, 137, 144,177, 181 Rocha, L. R. S. C., 377, 388 Roche, M., 198, 201, 270 Rodhain, J., 2, 3, 7, 9, 15, 17, 64 Rogers, L., 231, 267 Rogers, Q. R., 230, 270 Rogers, S. H., 378, 388 Rogers, W. P., 189, 198, 212, 270, 280, 337, 358 Rohde, K., 323, 358 Rohrbacher, G. H., 295, 359 Roller, N. F., 26, 27, 28, 52, 64 Roman, E., 340, 359 Rose, G., 381, 382, 384 Rose, I. C., 306, 359 Rose, J. H., 282, 291, 359 Rose, R. C., 235, 257 Rosen, H., 237, 270 Rosenbaum, R. M., 377, 389 Rosenberg, I. H., 217,218,223,231,238, 247, 270 Rosenberg, L. E., 231, 270 Risenthal, S.,228, 270 Roslien, D. J., 17, 64 Ross, A., 240, 270 Ross, J. G., 192, 270, 288, 291, 292, 303, 359 Rossan, R. N., 88, I10 Rossi, D., 369, 374, 384, 388 Ross, A. E., 382, 388 Rossiter, L. W., 306, 310, 359 Roszmann, J. H., 88, 97, 108

410

AUTHOR INDEX

Rothe, W. E., 98, 104, 111 Rothman, A. A,, 226, 269, 270 Rothman, A. H., 226, 230, 242, 243, 269 Rothman, S.,162, 181 Rothschild, M., 341, 359 Rotunno, C. A., 235, 252 Roudabush, R. L., 3, 19,55 Rousseau, B., 237, 270 Rousselot, R., 17, 34, 64 Rowe, P. B., 240, 263 Roy, A. D., 222, 257 Rubin, A., 240, 270 Rubin, C. E., 241, 272 Rubin, W., 185, 270 Rudge, A. J. B., 341, 355 Ruff, M. D., 141, 155, 175, 222, 270, 373,384 Ruiz, C., 237, 249 Ruiz, R.,98, 99, 110, I11 Rumel, W., 231, 262 Rummel, W., 224, 254, 256, 262 Rune, S. J., 211, 212, 270 Russell, P. B., 71, 99, 110, 111 Russell, S. W., 301, 302, 359 Ruttloff, H., 222, 271 Ryerson, D. L., 3, 67 Ryley, J. F., 96, 103, 112 S Sachs, I. B., 3, 64 Sacktor, B., 220, 271 Sadudee, N., 91, 107 Sadun, E. H., 3, 64, 70, 112, 330, 359, 382,385 Saggiomo, A. J., 98, 112 Sakharoff, M. N., 31, 64 Salgado, J. A., 375, 376, 377, 387, 388 Salisbury, J. R., 316, 318, 359 Sallee, V. L., 239, 271, 277 Salvidio, E., 80, 102, 110, 112 Sambon, L. W., 8, 9, 10, 13, 17, 18, 19, 31, 64, 65 Sanchez, A., 229, 271 Sangalang, R., 70, 112 Sangalang, R. P., 91, 107 Sanguineti, V., 104, 108 Sanmartin, C., 3, 64 Santos, D. F., 116, 178 Santos Filho, M. F., 116, 180 Sanz, M., 375, 387

Sarles, M. P., 283, 309, 310, 324, 359, 363 Sarwar, M. M., 334,353 Sauer, M. C. V., 373, 388 Saunders, D. R., 241, 272 Saunders, S. J., 243, 271 Savage, A., 47,49, 65 Savage, D., 217, 218, 223, 264 Savage, D. C., 219, 250, 271 Savinov, V. A., 191, 271 Sawh, P. C., 243, 250 Saxe, L. H., 74, 76, 84, 85, 87, 88, 107, 113 Saz, H. J., 210, 211, 271, 371,388 Schacher, J. F., 331,359 Schad, G. A., 198, 199, 271, 325, 359 Scharrer, E., 237, 271 Schatzle, M., 320, 360 Schaudinn, F., 2, 65 Schedl, H. P.,244, 269 Scheibel, L. W., 78, 112 Schemer, J. F., 374, 388 Schiff, E. R., 223, 237, 238, 239, 271 Schilb, T. P., 21 I , 251, 271 Schildt, G. S., 3, 66 Schillinger, J. E., 332, 360 Schilling-Torgau, V., 327, 350 Schlaaf, C., 333, 360 Schmid, F., 320, 360 Schmidt, L. H., 70, 73, 82, 88, 92, 99, 102,110,112 Schnell, J. V., 72, 74, 112 Schoenfield, L. J., 223, 259 Schofield, P. J., 211, 268 Scholar, E. M., 373, 374, 388 Scholtyseck, E., 42, 65 Schroeder, W. F., 327, 362 Schuler, R., 212, 271 Schulert, A. R., 373, 384 Schultz, M. G., 91, 112 Schultz, S. G., 233, 234, 235, 241, 242, 243, 244, 252, 254, 257, 266, 271 272 Schulz, I., 209, 271 Schumacher, W., 192, 272 Schwartz, A. R.,74, 104, 107 Schwartz, B., 283, 323, 336, 360 Schwartz, G. F., 209, 253 Schwartz, P. S., 228, 266 Schwartz, W. B., 237, 270 Scott, H. H., 3, 65 Scott, H. L., 305, 360

AUTHOR INDEX

Scott, J. A., 323, 324, 360 Scrivener, L. H., 340, 360 Seabra, A. do Prado, 116, 178 Seddon, H. R., 199, 272 Segal, M. B , 237,256 Seghetti, L., 312. 360 Sengrnan, C. G.; 10, 18,65 Sell, K. W., 168, 176, 181 Sell, 0. E., 294, 364 Semenza, G., 233, 243, 244,253, 272 Seneriz, R., 152, 155, 176 Seneviratna, P., 48, 50, 65 Sen, N. N., 247,258 Senft, A. W., 373, 374, 382,388,389 Senft, D. G., 373, 374,388 Sergent, E., 3, 8, 15, 21, 65 Sewell, R. B. S., 3, 65 Shalkop, W. T., 311, 327, 360, 362 Shamir, N., 247, 260 Shapiro, S. S., 240, 259 Sharp, G. W. G., 248,267 Shaw, J. A., 90,106 Shaw, J. J., 2, 3, 60 Shearer, G. C., 320, 357 Shearin, S. J., 189, 220, 234, 242, 256 Sheehy, T. W., 88, 112 Shelton, G. C., 309, 360 Sherman, I. W., 76, 77, 81, 112 Shields, R., 210, 246, 272 Shiff, C. J., 152, 171, 172, 174,181 Shillinger, J. E., 330, 332, 360 Shimoda, S. S., 241, 272 Shinbo, M., 98, 112 Shindo, H., 240, 272 Shining, S., 244, 269 Shirai, M., 323, 360 Shivnani, G. A,, 320, 351 Shorb, D. A., 311, 360 Shore, S. R., 84, 106 Short, C. R., 77, 106 Short, R. B., 130, 131, 181 Shorter, R. G., 186, 272 Shrimpton, D. H., 212, 253 Shum, H., 237, 241,272 Shute, G. T., 70, 91, 107, 112 Siddiqui, W. A,, 72, 74, 112 Sieber, S. M., 377, 378, 388 Siege], B. W., 74, 96, 112 Silva, J. R., 91, 110, 375, 384 Silva, M. L. H., 383, 387 Silver, I. A., 212, 253 Silverberg, J. W., 248, 262

41 1

Silverman, P. H., 102, 106, 304, 305, 360 Sirnmonds, W. J., 223, 238, 272 Simmons, J. E., 200, 242, 269 Simmons, J. E., Jr., 230, 242, 243, 269 Simon, B., 209, 272 Simpson, C. F., 3, 25, 65 Sinclair, I. J., 281, 288, 356, 357 Sinclair, I. J. B., 281, 356 Sinclair, K. B., 191, 272 Sing, A. K., 186, 203, 263 Singh, T., 104, 112 Siperstein, M. D., 229, 254 Siu, P. M. L., 77, 112 Sivadas, C. A., 48, 65 Sjovall, J., 208, 222, 251 Skelton, F. S., 81, 112 Skidmore, L. V., 26, 27, 34, 48, 65 Skou, J. C., 225, 272 Sladen, G. E., 225, 237, 258, 270 Sladen, G. E. G., 207, 208, 233, 235, 236, 272 Slais, J., 193, 272 Slegers, J. F. G., 245, 276 Slighter, R. G., Jr., 81, 106 Sloan, J. E. N., 313, 320, 351, 356 Small, D. M., 223, 255, 259 Small, N. C., 247, 238, 239, 271 Smith, C. C., 74, 88, 96, 97, 108, 112 Smith, C. S., 81, 112 Smith, J., 223, 264 Smith, J., Jr., 99, I10 Smith, J. A., 383, 389 Smith, J. G., 217, 223, 264 Smith, J. H., 118, 119, 121, 122, 123, 124, 125, 127, 128, 129, 130, 131, 133, 138, 139, 144, 146, 148, 169, 181 Smith, K., 241, 262 Smith, M. H., 21 1, 272 Smith, Th., 18, 65 Smith, T. M., 155, 181, 372, 389 Smith, W. C., 321, 327, 363 Smith, W. N., 293, 326, 360, 362 Smithers, R., 120, 158, 159, 160, 165, 167, 169, 170, 171,176 Smithers, S. R., 383, 389 Smithurst, B. A., 91, 112 Smulders, A. P., 245, 272, 277 Smyth, D. H., 209, 216, 229, 231, 233, 235, 241, 242, 243, 249, 260, 261, 266, 272, 273

412

A U T H O R INDEX

Smyth, J. D., 138, 181, 184, 187, 188, 189,200,223,225, 226, 236, 244, 246, 261, 273, 341,349 Smyth, M. M., 189, 273 Snyder, C. H., 331, 333,345 Sobotka, H., 240, 253 Sodeman, T. M., 81,112 Sodeman, W. A., Jr., 139, 148, 153, 154, 181, 247, 273 Sugandares-Bernal, F., 121, 148, 149, 180, 192, 273 Sokolic, A., 283, 360 Solberg, L. I., 211, 212, 235, 236, 268 Soldati, M., 104, 108 Solimano, G., 228, 273 Solin, M., 222, 249 Solis, J., 49, 59 Sollod, A. E., 289, 301, 360, 361 Solomon, A. K., 189, 263 Sommerville, R. I., 198, 273, 284, 285, 287, 296, 337,358, 361 Son, C. K., 3, 65 Sonea, S., 89, 113 Sonnenwirth, A. C., 219,268 Soulsby, E. J. L., 315, 326, 330, 331, 337, 339, 361 Sousa, O., 3, 58 Southcott, W. H., 319, 361 Souza, C. P., 377, 389 Souza, J. P., de, 116, I78 Sparell, G., 84, 108 Spedding, C. R. W., 315, 316, 319, 354, 361 Spencer, R. P., 240, 241, 273 Spindler, L. A., 311, 361 Spira, D. T., 89, 102, 106, 112 Sprent, J. F. A., 331, 332, 333, 334, 335, 336, 349, 361, 362 Sprinz, H., 46, 66 Srivastava, H. D., 334, 362 Stabler, R. M., 3, 65 Stahl, W., 340, 362 Standard, L. J., 3, 59 Standen, 0. D., 169, 181, 371, 374, 383, 389 Starr, L. E., 25, 49, 66 Stauber, V. V . , 316,354 Steck, E. A,, 70, 112 Stegman, R. J., 382, 389 Stein, P. C., 122, 123, 124, 125, 126, 127, 128, 143, 168, 169,181

Stein, R. G., 104, 112 Steinmetz, P. R., 237, 273 Sten, A., 210, 255 Stendel, W., 333, 353 Stephan, J., 16, 34, 47, 48, 65 Stephenson, W., 189,259 Sterling, C. R., 35, 38, 40, 46, 65 Stevenson, N. R., 240, 273 Stewart, D. F., 315, 318, 362 Stewart, F. H., 330, 333, 362 Stewart, J. S., 240, 251 Stewart, T. B., 294, 297, 326, 327, 340, 362, 364 Stirewalt, M. A., 116, 118, 119, 120, 122, 125, 126, 127, 128, 130, 131, 133, 134, 135, 136, 137, 139, 140, 141, 142, 143, 144, 145, 146, 149, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 165, 167, 168, 169, 170, 171, 172, 173, 174, 175, 178, 179, 181, 182, 373, 384 Stirling, C. E., 231, 273 Stockdale, P. H. G., 302, 350, 362 Stockert, T. A., 72, 100, 111 Stoddart, E. D., 49, 65 Stoeckert, I., 209, 276 Stoll, N. R., 304, 315, 362, 363 Stone, W. M., 325, 326, 327,362, 363 Stoye, M., 323, 325, 326, 333, 350, 363 Strasser, H., 332, 363 Strauss, E. W., 238, 274 Streeter, A. M., 237, 241, 272 Strickland, G. T., 89, 112 Strickland, T., 88, 112 Strome, C. P. A., 35, 40, 41, 42, 52, 94, 106 Strover, F., 209, 271 Stunkard, H. W., 341, 363 Summerskill, W. H. J., 209, 230, 257, 268 Supperer, R., 282, 326, 327, 357, 363 Surgan, M. H., 240, 274 Sutorius, A. H. M., 80, 108 Swallow, J. H., 235, 274 Swendseid, M. E., 229, 271 Swietlikowski, M., 282, 363 Swinehart, B., 3, 55 Symons, L. E. A., 210, 215, 223, 247, 257, 274 Szustkiewicz, C., 74, 76, 77, 85, 87, 88, 113

AUTHOR INDEX

T Takos, M., 3, 66 Taliafe, W. H., 283, 363 Taliaferro, W. H., 283, 359,363 Tan, B. D., 199, 200, 201, 261, 274 Tanabe, A., 50,59 Tanaka, R. D., 195, 197, 274 Tanigoshi, L., 76, 77, 81, 112 Tanowitz, H., 377, 389 Tarrant, M. E., 381, 389 Tarshis, I. B., 24, 27, 33, 59, 66 Taufel, K., 222, 271 Tavares, E. C. P., 375, 388 Tavill, A. S., 247, 274 Taylor, A. E. R., 242, 259 Taylor, C. B., 231, 274 Taylor, E. L., 191, 274, 281, 282, 312, 328, 363 Taylor, E. W., 222, 274 Taylor, K. B., 219, 274 Teem, M. V., 225, 274 Tendeiro, J., 3, 8, 10, 11, 12, 66 Terry, R. J., 383, 389 Tenvedow, H. A., Jr., 81,108 Terzakis, J. A., 46, 47, 66, 87, 112 Terzian, L. A., 79, 87, 92, 112 Tetley, J. H., 307, 363 Theakston, R. D. G., 76,112 Theiler, A., 308, 363 Theiler, G., 199, 274 Thomas, B. A. C., 287, 292, 301, 355 Thomas, J., 247, 249, 325, 359 Thomas, J. N., 222, 274 Thomas, M. J. G., 91, 110 Thomas, R. J., 320, 321, 345,363 Thomas, S. C., 83, 113 Thompson, E., 237, 260, 261, 274 ‘Thompson, P., 89, 109 Thompson, P. E., 3, 66, 70, 90, 95, 98, 109, 112 Thonard, J. C., 151, 152,180 Thoonen, J., 300, 363 Thorpe, E., 192, 275 Thorsell, W., 188, 250 Threadgold, L. T., 118, 180, 188, 275 Threlkeld, W. L., 27, 48, 59, 285, 287, 292, 363, 364 Tidball, C. S., 185, 189, 252, 275 Timms, A. R., 372, 389 Tin, F., 70, 107 Tiner, J. D., 335, 364

413

Tirabutana, C., 102, 107 Titus, J. L.,*186,272 Tizianello, A., 80, 110 Tobey, E. N., 3,56 Tod, M. E., 311,353 Todd, A. C., 3, 56, 306, 328, 329, 340, 345, 364 Todd, J. L., 3, 66 Todd, J. R., 192, 270 Tokuyasu, K., 88, 110 Tomasi, T. B., 219, 275 Tomasini, J. T., 189, 231, 245, 275 Tonascia, J. A., 325, 359 Tong, M. J., 88, 112 Tongson, M. S., 330, 364 Torbert, B. J., 280, 355 Toriumi, T., 50, 59 Tormey, J. McD., 245, 272,277 Torrigiani, G., 89, 109 Trager, W., 74, 88, 112 Trainer, D. O., 3, 27, 48, 53, 66 Travares, W., 91, 110 Travis, B. V., 49, 66 Treadwell, C. R., 224, 238, 275, 276 Trefiak, W. D. T., 28, 38, 42, 46, 66 Trier, J. S., 185, 189, 205, 275 Trigg, P. I., 74, 76, 84, 87, 88, 96, 106, 108, 109, 113 Tripathy, K., 247, 275 Tripp, J. H., 228, 255 Troesch, V., 222, 258 Trump, B. F., 80, 108 Tse, H. C., 377, 387 Tubergen, T. A., 94,106 Tugwell, R. L., 328, 364 Tumlin, J. T., 49, 65 Turnberg, L. A., 211,212, 235,236,275 Turnberg, L. H., 235, 275 Turner, J. B., 240, 275 Turner, J. H., 298, 299, 306, 318, 348, 364 Turton, J. A., 193, 197, 200, 275 Twohy, D. W., 284,364 U Uegaki, J., 3, 66 Uglem, G. L., 231, 267 Ugolev, A. M., 220,222,241,242,275 Ullrich, K. J., 209, 271 Ulmer, M. J., 191, 193, 198, 205, 275 Umezawa, C., 229,271

414

A U T H O R INDEX

Underhill, G. W., 27, 48, 59 Upmanis, R. S., 96, 114 Urike, C., 336, 364 Urquhart, G. M., 192, 275, 281, 282, 287, 288, 289, 292, 293, 297, 301, 344, 348, 353,355,358 Uskokovic, M., 98, 106 Ussing, H. H., 237, 257 Uy, A., 141, 153, 159, 160, 165, 167, 170, 171, 182 V Vahouny, G. V., 224, 238, 275, 276 Vaidyanathan, S . N., 334, 364 Vaitkus, J. W., 88, 106 Van Cleave, H. J., 185,276 Van Deenen, L. L. M., 237, 276 Van den Berghe, L., 3, 34,66 Vanderberg, J., 46, 66, 89, 110 Vandenbranden, F., 2, 3, 7, 9, 17, 64 Vande Vusse, F., 191, 275 Van Dyke, K., 74, 76, 77, 80, 85, 87, 88, 107, 110, 113 Van Os, C. H., 245, 276 Vanreenen, R. M., 91, 110 Varute, A. T., 247, 276 Vatter, A., 133, 134, 179 Veeger, W., 241, 276 Veglia, F., 304, 308, 364 Vegors, H. H., 287, 294, 364 Velloso, C., 375, 388 Vercammen-Granjean, P. H., 131, 182 Vercruysse, R., 300, 363 Vial, J. P. C., 209, 262 Vianna, M. J. B., 377, 387 Vickers, M. A., 21, 23, 26, 28,47, 50, 57 Victor, T. A., 84, I06 Viens, P., 89, 113 Viera, W., 91, 110 Vilcek, J., 89, 110 Viljoen, J. H., 306, 310, 364 Vince, A., 217, 218, 258, 266 Vincke, I. H., 85, 113 Visser, J., 187, 276 Vivier, E., 47, 64 Vlassoff, A., 316, 317, 319, 346 Vogel, G., 209, 276 Vogel, H., 125, 182 Vogh, B. P., 74, 84, I08 Volkmar, F., 31, 66 Voller, A., 89, 91, 110, 112, 113 Volpe, B. T., 225, 276

Votteri, B. A., 88, 112 Vray, B., 92, 113 Vukovic, V., 200, 276 Vural, A., 296, 364 W Wagland, B. M., 298, 299, 305, 318, 348, 365 Wagner, A., 117, 130, 131, 182 Waldron-Edward, D., 237, 276 Walker, D., 24, 49, 66 Walker, J., 3, 7, 66, 31 1, 353 Walker, S. R., 84, 106 Walker, W. A., 241, 276 Walkey, M., 341, 365 Waller, E. F., 3, 62 Walliker, D., 96, 97, 113 Walshaw, R., 219, 265 Walter, R. D., 85, 88, 113 Walter, W. G., 104, 111 Walters, G. T., 293, 344 Walters, M., 118, 119, 122, 125, 126, 127, 131, 135, 138, 139, 142, 143, 144, 145, 146, 153, 154, 156, 162, 163, 167, 168, 169, 173, 178, 182 Ward, R. A., 46, 66 Wardle, R. A., 200, 276 Ware, A. E., 25, 64 Warhurst, D. C., 70, 74, 75, 76, 77, 81, 82, 83, 91, 94, 95, 102, 107, 109, 110, 111, 113 Warren, E. G., 334, 365 Warren, K. S., 383,389 Warren, L., 187, 276 Warren, McW., 81, 108 Warshaw, A. L., 241, 276 Wasfi, A. M., 376,387 Washburn, L. C., 98, 113 Washington, M. E., 81, 113 Wassileff, I., 335, 355 Watson, J. M., 200, 276 Waxman, S., 88, 113 Weatherly, N. F., 242, 276 Webb, J. L., 222, 243, 276 Webb, J. P. W., 211, 212, 258 Webb, R. A., 226, 228, 230, 276 Weber, M. C., 376, 385 Weber, T. B., 281, 365 Webster, G. A., 331, 332, 365 Webster, L. A., 236, 246, 276, 277 WedIey, S., 381, 389

AUTHOR INDEX

Weening, S., 224, 276 Wehr, E. E., 3, 58, 328,353 Wehr, F., 25, 27, 66 Weiner, I. M., 223, 224, 238, 277 Weinmann, C. J., 200, 277 Weinstein, I. B., 377, 386, 389 Weinstein, L. B., 377, 386 Weinstein, P. P., 284, 365 Weiss, E., 116, 119, 154, 155, 156, 157, 167, 168, 175, 373,384 Weiss, H. V., 228, 266 Weller, I., 46, 56 Weller, R. S., 246, 260 Wensvoort, P., 315, 365 Wenyon, C. M., 2, 31, 66 Werbel, L. M., 70, 98, 104, 110, 112, 370, 374, 382, 389 Werner, B., 229, 250 Werner, J. K., 373, 384 West, E., 3, 11, 19, 50, 55 West, J. R., 25, 49, 66 Westcott, R. B., 219, 220, 277 Westen, H., 326, 365 Westland, R. D., 382, 389 Wetmore, P. W., 3, 20, 66 Wetzel, H., 292, 346 Wetzel, R., 281, 292, 365 Whang-Peng, J., 377, 378,388 Wheeler, H. O., 189, 209, 210, 261, 277 Wheeler, K. P., 235, 277 Whichard, L. P., 76, 77, 80, 81, 110, 113 White, E. G., 313, 348, 365 White, H. B., 155, 181 White, L. A., 76, 81, 113 White, M., 229, 261 Whitfield, P. J., 197, 201, 253 Whiting, E. G . , 91, 106 Whitlock, J. H., 307, 318, 365 Whitlock, R. T., 189, 261 Whitlock, S . C., 340, 365 Whittam, R., 235, 277 Whitten, L. K., 296, 364 Whitty, C. W. M., 76, 109 W.H.O., 377, 378, 380,389 Wickware, A. B., 16, 47, 67 Wieth, J. O., 237, 257 Wigand, R., 200, 277 Wikel, S . K., 163, 164, 167, 168, 173, 174, 176 Wilde, J. K. H., 104, 106

415

Wilkin, S . A., 3, 67 Wilkinson, R. N., 81, 105, 113 Willerson, D., Jr., 82, 84, 85, 90,91, 92, 99, 102, 111, 113 Willet, G . P., 74, 110 Williams, E. D. H., 91, 110 Williams, H. H., 184, 277 Williams, R. E. O., 217, 277 Williams, R. T., 84, 106 Williams, S . G., 74, I l l , 113 Williamson, J., 77, 88, 113 Wilmoth, J. H., 329, 343 Wilson, 211, 216 Wilson, A. L., 314, 365 Wilson, G. I., 306, 364 Wilson, F. A., 239, 271, 277 Wilson, R. A., 236, 246, 277 Wilson, T. H., 211, 214, 216, 277 Winfield, G. F., 280, 365 Wingate, D. L., 225, 277 Wingstrand, K. G., 13, 19, 21, 24, 31, 47, 48, 67 Winne, D., 234, 277 Wise, I. J., 242, 264 Wittenberg, J., 247, 267 Wittner, M., 377, 389 Wohnus, J. F., 3, 67 Wolbach, S. B., 3, 66 Wolfensberger, H.R., 105, 113 Wombolt, T. H., 293, 349 Wood, F. D., 3, 67 Wood, S., 3, 67 Wood, S. F., 3, 67 Woodage, T. J., 381, 389 Woodcock, H. M., 14,67 Woolhouse, W. M., 379, 386 Worcester, P., 82, 92, 102, 112 World Health Organisation, 69, 70, 71, 73, 99, 102, 103, 105, 113,114 Wormsley, K. G., 210, 214, 216, 277 Worsley, D. E., 91, 110 Worth, D. F., 98, 108, 382, 389 Wostman, B. S., 205, 228, 250, 269 Wright, E. M., 216, 234, 237, 240, 245, 249, 254, 272, 273, 277 Wright, K. A., 35, 56 Wright, W. H., 335, 365 * Wrong, O., 210, 278 Wu, N. C., 220, 271 Wu, S. L., 225, 255 WUU,K.-D., 88, 110 Wykoff, D. E., 191,278

416

AUTHOR INDEX

Y Yajima, Y.,120, 124, 125, 127, 128, 129, 131, 142, 152,175 Yamada, S., 241, 278 Yang, Y.J., 16, 23, 26, 28, 33, 38, 51, 56.67 Yao;K. F., 191, 255 Yardley, J. S., 247, 249 Yarinsky, A,, 370, 374, 375, 378, 384, 389 Yeh, L. C., 48, 50, 61 Yielding, K. L., 76, 106 Yoeli, M., 46, 66, 89, 96, 108, 113, 114 Yokagawa, M., 192, 278 Yokogawa, S., 322, 323, 332,365 Yokoyama, Y.,241,278 Yoshida, T., 191, 278

Young, F., 3, 25, 65 Young, S., 376, 385 Yutuc, L. M., 332, 365, 366 Z Zahm, B. G., 382, 389 Zajicek, D., 3, 67 Zamcheck, N., 228, 240, 254, 273 Zavadovskii, M. M., 312, 366 Zeitune, J. M. R., de, 376, 377, 387 Zicker, F., 379, 380,386 Ziemann, H., 1, 12, 67 Zuckerman, A,, 89, 112 Zussman, R. A., 371, 372, 390 Zviagintsev, S. N., 312, 366 Zwart, P., 24, 49, 54 Zylber, E. A., 235, 252

Subject Index Page numbers in italics indicate illustrations

A

canis, location specificity, 191 Albanella pallida, host of Leucocytozoor Absorption by host intestinal mucosa laverani, 4, 8, 17 of amino acids, 229 Allium cepa root tips, effect of hycan. of electrolytes, 235-7 thone on, 377 of fat, 238 Allopava meleagridis, host of Leucocy of ions, 207 tozoon smithi, 10 of non-electrolytes, 23845 Amino acid of vitamins, 240-1 kbsorption, 228, 229, 241 of water, 245-6 by helminths, 242-3 reduction by parasites, 210 steady state of, 230 by parasite, 246 transport, 233 differences between mucosal and Aminoquinazoline derivatives, 98 tegumental systems, 231 Aminoquinolines, 83 Absorptive surfaces in helminths, 188-9 antimalarial action, 77, 103 Acanthocephala, 184 Amodiaquine, mode of action, 75 attachment, 185 sensitivity in chloroquine-resistan1 location, 197-8 strains, 90 Acanthocephalans. absorDtive surface, with tetracycline, 102 188 Anaerobes in intestine, factors affecting, Accipiter badius sphenurus, host of 218 Leucocytozoon martyi, 8 Anaplasma marginale infection in cattle, Anisus, host of L. mathisi, 8 104 Accipitridae, 8 Anus crecca (Querquedulla crecca), host Acetabular glands of cercaria, 118, 19, of Leucocytozoon simondi (= anatis), 7 126,132, 135-6, 166 Anatidae, 7 development, 13941 Ancylostoma caninum, enzymes, 153 arrested development, 3 2 3 4 histochemical reactions, 138-9 colostral transmission, 325 muscles, 134 infection, prenatal, 324-5 ultrastructure,. 136,. 140. 141 cause of malabsorption in host, 247 schistosomule, loss in, .119, 169, 170, migratory behaviour, 322-3 174 sex attractant of, 198 Acetyl-L-phenylalanine ethyl ester, certransplantation, 201 carial activity against, 151 duodenale in man Acetyl-L-tyrosine ethyl ester, cercarial arrested development, 324 activity against, 151 seasonal fluctuations, 325-6 Aedes aegypti, sporogonic stages of Ancylostomatidae, 322-6 Plasmodium gallinaceum in, 87 Anhinga r. rufa (Plotus rufus), host of Akiba, subgenus of Leucocytozoon Leucocytozoon uandenbrandeni, 7 caulleryi, 2 Anopheles stephensi, 79, 86 Alaria alata, location and migration, 191 metabolic changes of Plasmodium arisaemoides, location of adult, 191 berghei in, 78 417

418

SUBJECT INDEX

Anser domesticus, host of Leucocytozoon anseris, 7 Anseridae, 7 Anseriformes, 7, 16, 34 Anthelmintics, resistance of arrested larvae of Ostertagia ostertagi to, 293 Anthochaera chrysoptera, host ofleucocytozoon anellobiae, 14, 20 Antifols, antimalarial, 98, 104 resistance to, 70, 92-3, 99 Antimalarial agents, categories of, 83 mode of action, 83-4 Antimony-potassium tartrate (APT) and penicillamine treatment for schistosomiasis, 380-1 Antimycin A, 83 Aotus trivirgatus, host of Plasmodium fakiparum, 72, 73, 92, 94, 99 Ardea goliath, host of Leucocytozoon ardeae, 7 grayi, host of L. ardeotae, 7 Ardeidae, 7 Arrested larvae and retarded worms, distinction between, 280 Ascaridae, 328-336 Ascaridia columbae, tracheal migration, 328 galli arrested development, 329-30, 338 growth curves, 328 migratory behaviour, 328-30 susceptibility of male chicks, to, 340 Ascaris columnaris intermediate host obligatory, 335 migratory behaviour, 335 devosi intermediate host obligatory, 335 lumbricoides permeability of cuticle, 189 tracheal migration, 330 suum arrested development, 330-1 susceptibility of gilts to, 340 tracheal migration, 335 Ascorbic acid, absorption of, 240 Aspergillus sclerotiorum in production of hycanthone, 374 Aspicularis tetraptera susceptiblity of male mice to infection with, 340 Astiban, antischistosome, 370, 371

Asturinulla monogrammica, host of Leucocytozoon bacelari, 8 Athene noctuae, host of Leucocytozoon danilewskyi, 12, 19 Austrobilharzia americana, caudal myofibres, 134 terrigalensis, 160-1 Azocoll, activity for cercaria against, 150

B Bacterial-protozoan interactions in gut, 219 Bacterioides, 217 effect on bile salts, 223 Benzoyl-L-arginine ethyl ester, cercarial activity against, 151 Benzoyl-D, L-arginine-p-nitroanilide, cercarial activity against, 151 Bicarbonate absorption, 236 secretion, 235 Bifidobacteria, effect on bile salts, 223 Bile functions, 224 ionic constituents, 209 Bile acids, 223-6 absorption, 238-9 in rat, 224 enterohepatic circulation, 225 Bile salts, 221 functions, 224 Bilirubin, 224 “Black box” approach to transepithelial transport, 231-4 Bonas umbellus, host of Leucocytozoon bonasae, 10 Bradykinin, cercarial activity against, 151 Bunoderina encoliae, migration of, 192 Bunostomum trigonocephalutn, arrested development, 326 Butorides virescens, host of Leucocytozoon iowense, 7 C Calliobothrium verticillatum transport of glucose, 244 sodium and potassium, 236 Capercaillie, host of Leucocytozoon lovati, 17-8 Caprimulgidae, 13 Caprimulgiformes, 13, 19

SUBJECT I N D E X

Caprimulgus fossei (= Scotornis fossii), host of Leucocytozoon caprimulgi, 13 Carbohydrate gradients in parasitized animals, 203, 204, 205 Carbon dioxide in intestine, 210, 211, 212, 213 Carboxypeptidase, functions, 221 Carduelis chloris (=Passer chloris), host of Leucocytozoon seabrae, 14 Cartilage, cercarial activity against, 150 Caryophyllaeus laticeps, maturation coincident with host spawning, 341 Casein, cercarial activity against, 151 Cattle, infections in of Dictyocaulus viviparus, 281-2 of Haemonchus placei, 303 of Oesophagostomum radiatum, 311 of Ostertagia ostertagi, 287-95 of Trichostrongylus axei, 295 spring rise in worm numbers, 320 Cebus monkeys, antischistosomal cure with hycanthone, 374-5 schistosomicidal action of oxamniquine in, 379 Centropus bruchelli, 10 superciliosus, host of Leucocytozoon centropi, 10 Ceratopogonid hosts for Leucocytoroon, 27, 32 Cercaria of Schistosoma mansoni characteristics, 166-7 embryonic development, 119 digestive tract, 145 excretory system, 148-9 gland cells, 1 3 9 4 glycocalyx, 127 metabolic activity, 156 tegumental structure, 123-4 emerged, free-swimming appearance, 132 digestive tract, 1 4 4 5 enzymes, 149-54, 372 penetration, 143 excretory system, 146-8 flame cells, 146, 147 glands, 135-9 functions, 142-4 histochemical reactions, 138 ultrastructure, 136-7 glycocalyx, 125-7

419

responses to tests, 122, 123 metabolic activity, 154-5 glycogen, 373 musculature, 133-5 nervous system, 132-3 sensory papillae, 129, 130, 131 penetration by, 161-2, 171-4 structure, 116, I 1 7-9 spines, 128-9 sucker, oral, 137 tegument, 121, 123 Cercariae, activity of homogenates of, 152 to schistosomules, 161 culture in Rose chambers, 162-3 Cercarial emergence from snails, surface permeability control function, 128 Cercopithecus aethiops centralis, host for Schistosoma mansoni, 370 C. seboeus, good host for S. mansoni, 370 Cestoda, 184 attachment to intestinal mucosa, 185 Cestode acidification by, 222 circadian migration, 195-7 infections, adhesion, 187 location in small intestine, 192 scoleces, evagination, 225 tegument, absorptive area, 188 complexity, 184 Charadriidae, 12 Charadriiformes, 12, 18 Chickens as hosts of Leucocytozoon spp., 17, 18, 24, 26-7 immunity to L. caulleryi, 51 pathoiogy, 48 prevention of leucocytozoonosis, 50 infections of Ascaridia galli, 328-30 Heterakis gallinae, 336 Chloride anions, absorption of, 235 Chloropsis aurifrons frontalis, host of Leucocytozoon chloropsidis, 13 cochinensis jerdoni, host of L. enriquesi, 13 Chloroquine biochemical effects of, 76, 77 on haemozoin, 74, 82 mechanism of malarial resistance, 94 mode of action, 74 in parasitized erythrocytes, 75-6

420

SUBJECT INDEX

Chloroquine (cont.) -resistant malaria need for gametocytocidal agent, 97 strains of Plasmodium berghei, 94-5 P . falciparum, 70 responses by P . falciparum and vivax, 73 Chloroquine diphosphate, 100 Cholesterol, transport by bile salts, 224 Chondroitin sulphates, cercarial activity against, 150 Chondromucoprotein, cercarial activity against, 150 CHR (antischistosome serum), 125 Chylomicron triglyceride fatty acids, 229 Chymotrypsin, 221 inactivator, 222 CI 679, potent antimalarial antifol, 98 Ciconibiormes, 6 Cinchona alkaloids, 83 Cinconiformes, 7 Circaetus gallicus, host of Leucocytozoon circaete, 8 Cittotaenia denticulata and pectinata, sites in rabbit, 199 Clociguanil, 85, 86, 99 Clonorchis sinensis, migration to liver, 191 Clostridia, effect on bile salts, 223 Cnephia ornirhophilia, host of Leucocytozoon simondi, 21, 33 Coccyzus americanus, host of Leucocytozoon coccyzus, 1 1 Colinus Virginia, 17 Collagen, cercarial activity against, 150 Colon, 186 absorption in, 208 ionic concentrations in, 209, 210 Columbidae, 12 Columbiformes, 12, 19 Cooperia curticei in sheep arrested development, 296 spring rise, 31 3 C. oncophora arrested development, 297, 298 C . pectinata arrested development, 297 C. punctata arrested development, 297, 298 Coracias abyssinica, host of Leucocytozoon leitaoi, 1 1 benghalensis, host of L. coraciae, 1 1

Coracidae, 11 Coraciiformes, 1 1, 18 Cormorant, host of Leucocytozoon vandenbrandeni, 4, 5 Cortisone-treated calves infected with Ostertagia ostertagi, 288 Corvidae Corvus corax, host of Leucocytozoon sakharofi, 13 corone, host of L . zuccarellii, 13, 19 Coturnix chinensis, host of Leucocytozoon mesnili, 9 Crinifer piscator, host of Leucocytozoon dinizi, 12 Crithidia fasciculata, effects of mepacrine on, 77 Crowsas host ofleucocytozoa, 19,20,31 infection with L . sakharofi, 47, 48 Cryptocercus punctulatus gametogenesis of parasites, 341 Cuculidae, 11 Culculiformes, 10, 18 Culicoides, vector of Leucocytozoon caulleryi, 2, 32 arakawae, 33, control, 50 sporogony in, 30 circumscriptus, 33 odibilis, 33 schultzei, 33 Cycloguanil, 87, 96 effect of menoctone on, 81 resistance in Lactobacillus casei to, 97 Cycloguanil embonate with acedapsone (Dapolar), 104 hydrochloride, 101

D Dapolar (cycloguanil embonate and acedapsone), 1 0 4 Dapsone, 80 antimalarial action of, 85 diformyl analogue of (DFD), 84 Dendritobilharria pulverulenta, location in arteries, 191 Derjaguin - Landau - Veriwey - Overbeed (DLVO) theory, 187 adhesion mechanism, 187 Dermalinia bovis, reproduction stimulated by corticosteroids in host, 341 Desnitrothiazolines, schistosomicidal activity of, 382

S U B J E CT I N D E X

Dictyocaulidae, 281-4 Dictyocaulusfir’aria,282-3 arrested development, 283 viviparus arrested development in lungs of cattle, 281-2 seasonal factors in, 281-2 Diformyl dapsone (DFD), 80, 84 metabolic fate of, 74 multiple drug-resistant strains, 102 and pyrimethamine, 104 Digestive cecum of cercaria, 132 enzymes in mammalian small intestine, 220, 221-3 Dihydrofolate reductase inhibitors (antifols), 70, 85-8, 101 new, 98-9 resistance to, 96-7 Diphyllobothrium latum, effect on vitamin B12, 241 Diplococcus pneumoniae, dihydrofolateresistant mutants, 97 Dipylidium caninum, location specificity in cat, 192 Dove, host of Leucocytozoon, 20 Doxycycline, antimalarial action of, 102 Duck as host of Leucocytozoon simondi, 16, 21, 23 chronic leucocytozoonosis, 50-1 mortality due to, 47 parasitaemia, 27 relapse in spring, 32 Duodenum COz in lumen of, 212 concentration of ions in, 209 luminal contents of, 210 E Echinococcus granulosus, tegument, 189 Elastase digestion, 221 Elastin, cercarial activity against, 150 Emberiza cirlus, host of Leucocytozoon cambourmaci, 15 Emberizidae, 15, 21 Enterobius vermicularis, 247 Enterokinase, functions of, 221 Enzyme inhibitors, 222-3 Erythromycin, antimalarial action, 102 Escape gland of cercaria, 132, 135, 138, 139 of embryonic cercaria, 140-1 functions, 142

42 1

Escherichia coli T bacteriophage effect of hycanthone on, 377 Estrilididae, 15, 21 Eurystomus afer, host of Leucocytozoon francae, 11 gularis, host of L . eurystomi, 11 F Falconidae, 8 Falconiformes, 8, 17 Fasciola hepatica concurrent infection with Fascioloides magna, 201 Hymenolepis microstoma, 201 migration to liver, 191 Flame cells of cercaria, 146-9 ultrastructure, 147 Folic acid absorption, 240 Fowl, cells invaded by Leucocytozoon, 31 Francolin harbouring Leucocytozoon mesnili, 3, 18, 32 Francolinus bicalcaratus, host of Leucocytozoon francolini, 9 sinensis, 9 Fringilla coelebs, host of Leucocytozoon fringillinarum, 14 Fringillidae, 14, 20

G Galliformes, 9, 17-8 Gallusgallus, host of Leucocytozoa, 9, 17 Garrulus glandarius, host of Leucocytozoon laverani, 13 Gastrointestinal canal, mammalian, 183-249 immunological mechanisms and microflora, 218-9 regions, 185 Geese as hosts of Leucocytozoa, 16, 24 absence in blood in winter, 32 mortality, 47 Gelatin, cercarial activity against, 151 Gelatinase in preacetabular glands of cercariae, 153 Gingival tissue, activity of cercaria against, 150 Glaucidium brasilianum, host of Leucocytozoon lutzi, 12 Glucose absorption, 244

422

SUBJECT INDEX

Glucose (cont.) Haemosporina, 2 gradients in rat small intestine, 227 Haemozoin, clumping of, 76 Glycerol, cercarial activity against, 151 by action of chloroquine, 74 Glycocalyx of cercaria, 118, 121, 125-7, inhibitors of, 82 166 in primaquine-resistant Plasmodium functions, 128, 143 berghei, 96 responses to cytochemical and histo- Haliaetus vocifer, host of Leucocytozoon chemical tests, 122, 123, 126-7 audieri, 8 surface permeability, 156 Hamsters, antischistosomal action of “Glycocalyx” (surface coat of helhycanthone in, 3 7 4 5 minths), replacement of, 187 oxamniquine in, 379 schistosomule, loss in, 119, 124, 174 Hawks as hosts of Leucocytozoon, 17,31 Glycyglycine (gly-gly), cercarial activity Head gland of cercaria, 135, 136 against, 151 histochemical reactions, 138 Grackle infected with Leucocytozoon ultrastructure, 137 fringillinarum, 2?, 25 of schistosomule, 142 Graphidium strigosum in rabbits Heligmosomatidae, 28 1-4 immature worms, 301 Helminth spring rise, 322 absorptive surfaces, 188-9 Grouse, infected with Leucocytozoon, attachment, 184-5 31, 32 -host adhesion, 187 with L. bonasae, 24, 49 interactions in gastrointestinal with L. lovati, 18 canal, 183-248 Gruiformes, 11, 18 migrational stimuli, 205, 206 Guanylhydrazones, antimalarial actisite selection, 191-206 vity, 103 Helminths, Guinea fowl, 18, 26 metabolism, COZ fixation, 210-1 Heparin, cercarial activity against, 150 Heptalaminate membrane of schistosomule, 124, 166 H development during conversion, 174 Habronema spp. in horses Heterakidae, 336 Heterakis gallinae, arrested developarrested development, 336 Haemamoeba ziemanni in owls, 2 ment, 336 Haemin, synthesis of haemozoin from, Hide powder, cercarial activity against, 150 76 Haemoglobin, cercarial activity against, Hirundinidae, 15 151 Homeostatic regulation in intestinal lumen, 228-3 1 Haemonchus contortus in sheep, 299, Horses, infection with Habronema spp., 304,314, 317 336 development Hyaluronic acid, activity of cercaria adult worms, loss of, 307 against, 150 arrested, 303-7 resumption of, 306-7, 319 Hycanthone, 374-8 antischistosome, 369, 371 epidemiology, 320 chemical structure, 374 infections dosage and side effects, 376-7 absence of effect of sex on, 340 theramutical activity, 374 spring rise of, 318 placei in calves Hydatigera (Taenia) taeniaeformis, location, 192 arrested development, 303 Haemoproteus mefchnikovi, crystalloid Hydrogen ions in intestine, 211,215 216 effect on bacteria, 218 inclusion in ookinetes, 46

423

SUBJECT I N D E X

Hydrogen ions in intestine (cont.) secretory mechanism, 236 effects on transport processes, 237 5-Hydroxytryptamine (5HT), migrational stimulus of helminths, 205 Hymenolepis diminuta absorption of glucose, 226, 244-5 lipid, 240 sodium and bicarbonate, 236 vitamins, 240 amino acid pool, 229 biomass distribution and carbohydrate gradients, 203, 204-5 concurrent infections with H . nana, 199 Moniliformis dubius, 200 crowding effect, 200 glucose gradients, 227 growth with increased glucose, 228 inhibited by amino acid, 230 homogenates, ATPase in, 231 malabsorption in rats, 247-8 migration, 193-7 responses, hypotheses, for, 201-6 pH reduction of intestinal lumen, 219 scolex attachment sites, 185, 194-7 transplantation, 201 H. microstoma concurrent infection with Fasciola hepatica, 201 crowding effect, 200 hosts and sites, 192-3 immune responses to, 199 transplantation, 201 Hyostrongylus rubidus arrested development, 300-1 seasonal trend in, 300, 321 increased egg counts in lactation period in pigs, 321

I ICI, 56, 780, 96, 103 Icteridae, 20 Ileal juice, ionic constituents, 209 Ileum absorption, 208 of bile acids, 238 COa in lumen, 212 concentrations of ions in, 209

decrease in peristalsis, 186 date of transit through, 226 Intestinal epithelium, 221 absorptive surface, 189-91 and helminth tegument, competition between, 203, 226 differences in, 234 digestive enzymes, 220, 221 and lumen, morphology and function, 185-6 lumen isotonicity in contents, 208 translocation of solutes, 232-4 “black box” approach, 231 microbial ecology, 217-20 parasites cause of reduction of water and electrolytes in host, 210 secretions ionic constituents, 209 Intestine osmolality of fluid, 210 small, of man, 235-7 and large, -regions, 185 volume of water and and electrolytes, 207 Irenidae, 13 Itygonimus ocreatus, 199 torum, sites in mole, 199 Ixobrychus sinensis (Ardetta sinensis), host of Leucocytozoon leboeufi, 7 Ixus hainanus (Pycnonotus sinensis), host of Leucocytozoon brimonti, 13 J Jejunal juice, ionic constituents, 209 Jejunum absorption of fat, 238 fluid and electrolytes, 208, 235 vitamins, 240 COz in lumen, 212 concentration of ions, 209 rate of transit through, 226 transport of solutes, 235

K Kaupifalco monogranimicus host of Leucocytozoon bacelari, 8 Kedem equation for flow through input and output systems, 234 Keratin, cercarial activity against, 150

424

SUBJECT INDEX

.

L

relapse, 32 schizonts in grouse, 24 Lactation period, suspension of loss of sporogony, 30 worms during, 318-9 transmission, 27, 33 Lactic acid, excretion by helminths, 248 L. boufardi, 14 Lactobacillus, 2 17 L. brimonti, 13, 20 casei, resistance to cycloguanil, 97 L. cambournaci, 15 Lagopus scoticus, host of Leucocytozoon L. caprimulgi, 6, 13, 19 lovari, 10 L. caulleryi, 3, 5, 9, 19 Lecithins, 223, 224 classification, 2 Leptotriches of flame cells, 147, 148 distribution, 4, 9 Leucocytozoidae, 2 gametocytes, round, 17 distinguishing features, 46 hosts Leucocytozoon, 1-52 chickens, 26-7, control, 50 cells invaded by, 30-2 immunity, 51 classification, 1-3 culicoides, 27, 32 distribution, 7-15 schizogony, 245 epizootiology, 35 sporogony, effect of temperature on, exflagellation, 40-2 30 gametocytogenesis, 38-40 L . centropi, 10, 18 hosts L . chloropsidis, 13, 20 invertebrate, 27 L. circaeti, 5, 8, 17 vertebrate, 7-15 L. coccyzus, 5 , 11, 18 life cycles, 21-35 L. coraciat?, 6, 11, 18 macrogametocytes, 5, 6 L. costae, 5, 10, 18 shape and size, 7-15 L. danilewskyi, 2, 6, 12, 19 relapse, 32 gametocytes, 2, 16, 26 rhoptries, 35, 37, 38, 43, 45 exflagellation, 28 specificity, 34 hosts, 2 transmission, 32-3 owls, 24-5, parasitemia in, 32 ultrastructure, 3547 swallows, 21 cytomeres, 36,37 simuliid, 27 gametocyte, 39 megaloschizogony, 38 merozoite, 36, 37 sporogony, 30 microgamete, 41 L. dinizi, 6, 12, 19 oocyst, 44 L. dubreuili, 6, 14, 20 ookinete, 43 gametocyte, 28 schizont, 36, 37 hosts sporozoite, 44,45 robin, 23, 25; parasitemia in, 32 L. anatis, 16 simuliid, 27, 33 L. andrewsi, 5, 9, 17 megaloschizont, 29, 38 L. annelobiae, 6, 14, 20 oocyst, 29; ookinete, 29 L. anseris, 7, 16, 34 schizogony, 21, 23, 25, 29, 38 L. ardeae, 5, 6, 7, 16 sporozoites, 29, 30 L. ardeolae, 6, 7, 16 L. enriquesi, 13, 20 L. audieri, 5, 8, 17 L. eurystomi, 6, 11, 18 L . bacelari, 5, 8 L. francae, 11, 18 L. beaurepairei, 9, 17 L. francai, 14, 20 L. berestnefi, 6, 13, 19 L. franchini, 8, 17 L. bonasae, 5, 10 L. francolini, 5, 9, 17 gametocytes, 2, 16, 26 L. fiingillinarum, 6, 14, 20 megaloschizonts, 25, 38 distribution widespread, 4, 16

SUBJECT INDEX

L. fringillinarum (cont.) hosts, 25, non-specificity, 34, 35 vectors, 27, 33 megaloschizogony, 38 microgametocytes, 28 oocysts, 30 schizogony, 25 L. galli, 9, 17 L. gentiii, 14, 20 L. giovannolai, 2, 14, 20 L. hirundinis, 15 L. iowensis, 5, 6, 7, 16 L. kerandeli, 5, 9, 17 L. laverani, 4, 8, 13, 17, 19, 20 L. Ieboeufi, 7, 16 L. Iegeri, 12, 16 L. leitaoi, 6, 11, 18 L. Iiothricis, 6, 13, 20 L. Iovati, 5, 10, 18 L. lutzi, 12, 19 L. mcleani, 9, 17 L. majoris, 6, 13, 20, 21 L. mansoni, 5 , 10, 18 L. tnarchouxi, 12, 19 microgamete with axoneme, 42 L. martyi, 8, 17 L. mathisi, 8, 17 L. melloi, 11, 18 L. mesnili, 3, 5, 9, 17, 20 L. mirandae, 2, 14, 20 L. molpastis, 13, 20 L. monardi, 6, 15 L. neavei, 5, 10, 17, 18 gametocytes, 26 oocysts, 30 sporogony, 30 vectors, 27 L. numidae, 5, 10, 18 L. pealopesi, 10, 17 L. ralli, 11, 18 L. roubaudi, 15 L. sabrazesi, 5, 9, 17, 18 infection in chickens, 33, 50 specificity, 34 L. sakharofl, 3, 6, 13, 20 gametocytes, 26 hosts crows, disease in, 47, 48 raven, 19 rooks, 26 simuliid, 27 megaloschizonts. 24

425

sporozoites, 30 L. schoutedeni, 5, 9, 17 hosts, chickens, 26 simuliid, 27, 33 oocysts, 30 sporogony, 30 L. schuffneri,9, 17 L. seabrae, 14, 20 L. simondi, 3, 5, 7, 16, 19 cultivation, 51-2 hosts ducks, 27, 50-1 geese, 24 turkeys, 48-9 vectors, 27, 28, 35 life cycle, 21-4 gametocyte, 2, 22, 38, 40 megaloschizont, 36, 37, 38 merozoite, 36, 37, 38 microgamete, 41 exflagellation, 40-2 microgametocytes, 28, 29 oocyst, 30, 42-3; ookinete, 43 schizogony, 22, 35-8 sporogony, 28, 30; sporozoites, 43-6 locomotion, 44,46 parasitemia, 23, 26, 27 pathogenesis, 47-9 ultrastructure, 35-47 variation in blood of duck, 341 L. smithi, 5 , 10 gametocytes, 26 hosts, turkeys, 18 specificity for, 34 vectors, 27, 33 L. sousadiasi, 6, 12, 18 L. struthionis, 4, 5, 7 L. toddi, 8, 17 L. turtur, 12, 19 L. vandenbrandeni, 4, 5, 7 L. ziemanni, 6, 12, 19 L. zuccarellii, 13, 19 Lieberkiihn, crypts of, 186 Limnodromus griseus, 34 Lincomycin, antimalarial action, 82, 102 effective use against chloroquine resistance, 92 pyremethamine resistance, 92 Liothrix Iuteus, host of Leucocytozoon liothris, 13 Lipid absorption. 239-40

426

S U B J E C T INDEX

Lipids, luminal, 229-30 Lonchura punctulata topela, host of Leucocytozoon roubaudi, 15 Lucanthone, comparison with hycanthone, 375 Lungworm larvae in faeces, increase in spring, 282 M Macracanthorhyncus hirudinaceus, location, 198 Magpie, cells invaded by Leucocytozoon, 31 Malabsorption brought about by helminths, 246-8 Malarial infections, immunosuppressive effects of, 89 Maleate, 222 metabolic and enzyme inhibitor, 243 ’ Mammalian intestinal canal, helminthhost interactions in, 183-249 Marshallagia marshalli, arrested development in, 296 Mastomys ma tafensis, infected with S. mansoni, schistosomicidal agents, 370 Meleagridae, 10 Meliphagidae, 14 Membrane digestion by trypsin and chymotrypsin, 222 -schistosomules, collection of, 157, 159, 160 theory for transport of solutes, 233 Menoctone, 96 antimalarial action of, 103 cause of mitochondria1 damage in Plasmodiumfallax, 81 Mepacrine, 83; biochemical effects of, 77 mode of action, 75 -resistant P . berghei, 95 Merula merula, host of Leucocytozoon, 31 Methotrexate, hepatotoxic as antimalarial, 99 schizontocidal action, 88 Micelles, 223, 224, 238, 239 Michaelis-Menten kinetics, 242,243,244 Microtriches of cestode tegument, 188-9 Microvilli, 186 structure and functions, 189-190 Migration in acanthocephalans, 197-8 in cestodes, 193-7

in H. diminuta, 202-5 stimuli, 205-206 in nematodes, 198-9 in trematodes, 191-2 Minocycline, 102 Miracil D, 369, 371 Moniezia expansa galactose in cerebrosides of, 226 immune response to, 199 Moniliformis dubius concurrent infection with H. diminuta, 200 effect on host enzymes, 247 location and migration, 197-8 niche specialization, 200 Monkey, green (Cercopithecus seboeus) good host for S. mansoni, 370 vervet (C. ae. centrulis) host for S . mansoni, 370 Musophagidae, 12 Musophagiformes, 12, 19 Myocyte of cercaria, 133 Myofibres of cercaria, 133 N Necator suillus, prenatal infection in piglets, 324 Neguvon, removal of adult 0. Ostertagi by, 288 Nematode cuticle, 189 -intestinal flora interactions, 219-20 Nematodes, arrested development of, 280-343 factors affecting adult worms, loss of, 286 presence of, 288 autumn grazing, 288 host resistance, 286, 288, 298, 305 infections, size of, 285, 305, 329 seasonal, 281-2, 286,288-9, 329 variation in, genetic basis for, 290 feeding of, 185 location, 198-9 Nematodirus battus, arrested development, 298, 299 pathophysiology, 247 filicollis, arrested development, 298, 300 spathiger, arrested development, 298-9 Nematospiroides dubius, susceptibility of male mice and rats to, 340

427

SUBJECT INDEX

Neoascaris vitulorum, colostral and prenatal infection of calves, 334 Neoechinorhynchus rutili in stickleback, 341 Neuropile of cercaria, 132 Nicarbazin, antischistosome, 370, 383 Nippostrongylus brasiliensis inhibition of development, 2 8 3 4 effect of lactation in rats, to, 317 location and migration, 199 persistence longer innew-bornrats, 341 susceptibility of old male hamsters to 340 transplantation, 201 Niridazole, prophylactic antischistome, 370, 371, 376 Nitrothiazoline, schistosomicidal activity, 382 Nitrovinylfuran derivative (SQ 18 506) antischistosome, 381-2 Non-penetration schistosomules, collection of, 161 -stimulated schistosomules, 162-4 Numida meleagris, host of Leucocytozoon, 10, 34

0 Obeliscoides cuniculi, parasite of cottontail arrested development in rabbits, 301-3 Oesophagostomurnspp., 308-1 2 arrested development in abnormal hosts, 3 11-2 rise in egg counts in lactation of pigs, 321 columbianum development and larval nodules, 308-10 eggs passed and epidemiology, 320 dentatum, arrested development, 3 1 1, 337 longicaudiurn, histotrophic phase, 3 11 quadrispinulatum, 31 1 radiatum, arrested development and nodules, 31 1 venulosum, life history, 3 10 Onicola canis, location, 198 Opalina ranarum, influence of host on sexual reproduction, 341 Ostertagia spp., arrested worms, development of, 316-7, 319

spring rise in sheep, 313, 314 susceptibility of female lambs to, 340 circumcincta,284-7; adult worms, 291 arrested development, 286, 318, 319 ostertagi, 287-95 arrested development, factors influencing, 288-9 Ostertagiasis, type 11, “winter”, 292-3 Otus scops, host of Leucocytozoon danilewskyi, 19 Ouabain, 236 effect on ATPase, 231 inhibition by, 235 Ovomucin, cercarial activity against, 151 Owl, infection with Leucocytozoon, 1, 2, 4, 19 with L. danilewskyi, 24-5 absence of Leucocytozoon in winter in blood of, 32 Owl monkey (Aotus trivirgatus), 72, 73 (see also A. trivirgatus) Oxamniquine, 369, 378-80 chemical structure, 378-9 treatment for schistosomiasis dosage and side effects, 379-80 Oxidation-reduction potential (Eh) in gastro-intestinal lumen, 216, 217 Oxygen in intestine, 211, 212, 214, 215 effects on anaerobes, 218 bacterial growth, 218 tensions in lumen, 218 Oxytetracycline, schizonticidal action, 81 P Pamaquine, biochemical effects, 80 Pancreatic enzymes, 220, 221 juice, ionic constituents, 209 Paragonimus kellicotti, migration response to attractant, 192 Parahaemoproteus, 42 velans, ookinetes, 46 Paraleucocytozoon lainsoni in lizards, 2 Parascaris equorum, tracheal migration, 335 Paridae, 13 Parulidae, 20 Parus major, host of Leucocytozoon majoris, 13 Passalurus ambiguus in rabbits spring rise, 322

428

SUBJECT INDEX

Passer griseus, host of Leucocytozoon monardi, 15 Passeriformes, 13, 19 Pavo cristatus, host of Leucocytozoon martini, 9 Pelecaniformes, 4, 7 Penicillamine, 38 1 Peptide absorption, 241-2 Perikaryons of cercaria, 118, 121, 123, 133, 142, 174 embryonic cercaria, 124 schistosomule, 124 PAS (periodic acid-Schiff), 122, 123, and glycocalyx, 126, 127 Petronia petronia, host of Leucocytozoon gentili, 14

pH effects in intestine, 213, 214, 215-6 of pancreatic enzymes, 220 on absorption and transport, 237 on intestinal microflora, 218 Phalacrocoracidae, 7 Phasianidae, 9 Phasianus colchicus, host of Leucocytozoon macleani, 9, 17 Pheasant as host for Leucocytozoon, 17, 18 Phenanthremethanol, 83, 98 compound WR122, 455, P. berghei strain resistant to, 90 Phenothiazine, 286 effect on Oe. columbianum in sheep, 310 Trichonema in horses, 308 Phosphofructokinase of S. mansoni, inhibition of, 372 Pica pica, host of Leucocytozoon berestnefi, 13 Pigs infection with Hyostrongylus rubidus, 300 Oesophagostomumlongicaudum,3 1 1

prenatal and colostral transmission with Strongyloides ransomi, 32G7 worm egg counts during lactation, 320 Plasma, ionic constituents, 209 Plasmalemma of cercaria, 121, 123 Plasmodium, microgametes, 42 berghei

antimalarial action of chloroquine on haemozoin of, 82 mepacrine on, 77

pamaquine and primaquine on, 79, 80, 81 sulphonamides, by binding to enzymes, 85 culture of, 74 enzymes, 88 in Anopheles stephensi response to pyrimethamine, 86,87 metabolism, 78, 82-3 mitochondria, 79 -mouse system, 71 response to chloroquine and iron, 77-8 ookinetes, 46 resistance to antifols, 92, 97 to chloroquine, 98 and pyrimethamine, 93 sulphaphenazole, 93 to mepacrine, 95 to primaquine, 96 cross-r. and sensitivity, 90 effective drugs against, 90 mechanism of, 94-5 b. nigeriensis, action of pyrimethamine on oocyst, 86 cathemerium in the canary, 71 chabaudi, effect of sulphonamides on, 85

cynomolgi, effective use of lincomycin, 82,92 action of RC12, 103

response to pyrimethamine and cycloguanil, 87 in rhesus monkey, 73 c. bastianelli, sporontocidal action of RC12, 81 ceylonensis, 8 1 falciparum

activity of antimalarial compunds on, 1 0 0 - 1 sulphalene-trimethoprim, 104 sulphamethoxazole - trimethoprim, 81 cultures for response to antibiotics, 74

resistance to chloroquine, 83, 91 and antifols, 70, 71 pyrimethamine, 90 multi-drug, 98 pyrimethamine, 92 sulphonamide-antifol, 92

429

SUBJECT INDEX

Plasmodium (cont.) falciparum (cont.) response to pyrimethamine and cycloguanil, 87 in Aotus trivirgatus, response to antimalarials, 72, 73, 92 resistance to chloroquine, 92, 94 and pyrimethamine, 98-9 fallax mitochondria1 damage, 81 effect of primaquine on schizonts, 78 resistance to primaquine, 94 gallinaceum, 42, 47 in Aedes aegypti, 87 in chick, 71 ; primaquine-resistant, 94 knowlesi cultures, 74 cytochrome oxidase of, 78 DNA-chloroquine binding in, 76-7 action of sulphalene and trimethoprim on, 104 response to pyrimethamine, 87 lophurae effect of antimalarials on, 77, 81 thymidine synthesis in, 88 vinckei use in screening of antimalarials, 71 chloroquine-resistant, 89-90 enzymes in, 88 vivax in owl monkey responses to drugs, 73 schizontocidal action of methotrexate, 88 oxytetracycline, 81 Ploceidae, 14, 21 Pocidae, 20 Polymorphus minutus in duck absorptive area, 188 Polystoma stellai in frog, influence of host hormone on, 341 Potassium absorption, 235 Primaquine biochemical effects, 80-1 ; morphological, 78-9 use against chloroquine-resistant malaria, 97 resistance to, 94, 95-6 Probenecid, 84 Proguanil, 84, 85

Prosimilium demarticulatum, host for Leucocytozoon, 33 Protease activity of cercarial extracts, 152 Protein absorption by intestine, 241 Pternistis afer swynnertoni, host of Leucocytozoon pealopesi, 10 Pycnonotidae, 13 Pyrnonotus c. cafer, host of Leucocytozoon molpastis, 13 Pyrimethamine, 83, 94 binding to enzymes, 85 mode of action, 74 -resistance, 92, 96 responses by malarial parasites, 73, 87 Pyrocatechol RC12, antimalarial action, 103

Q Quail, 18 Quinine analogues, 98 cross reactivity to, 91 resistance to, 90 mode of action of, 77 responses by malarial parasites to, 73 -tetracycline treatment, 102, 105 Quinoline, ICI56, 780, 96 Quinolinemethanols, 83, 98 R Rallidae, 11 Rallus aquaticus, host of Leucocytozoon ralli, 11 Rabbits, host of Graphidium strigosum, 301 spring rise in worm burdens of, 322 infections of Trichostrongylus retortaeformis, 295 Rats infected with H. diminuta decrease in growth rate, increase in caloric intake, 228 malabsorption in, 247-8 osmolality of intestinal fluids, 210 infected with Nippostrongylus brasiliensis, 283 4 pathophysiology, 247 small intestine of, carbohydrate gradients, 204 Rattus norvegicus, diet and digestion, 226 Raven, host for Leucocytozoon sakharofi, 19, 31

430

SUBJECT INDEX

Rhoptries in Leucocytozoon, 35, 37, 38, 43,45 Riboflavin absorption, 240 Robin infected with Leucocytozoon dubreuili, 25 parasitemia, 32 Rotenone cyanide, 83 inhibitor of clumping, 82

Scolex attachment sites, helminth, 194-7 variation with host’s feeding cycle, 203 Scolopacidae, I2 Scolopax rusticola, host of Leucocytozoon legeri, 12 Seasonal factors affecting development in Ascaridia galli, 329 Cooperia oncophora, 297 Dictyocaulus viviparus, 28 1-2 S Haemonchus in sheep, 306 Sagittaridae, 9 free-living stages of nematodes, 289Sagittarius serpentarius, host of Leuco92, 338 cytozoon beaurepairei, 9 Nematodirus Jilicollis, 299-300 Salmonella, mutagenic effect of hycanOesophagostornum in sheep, 3 10 thone and miracil D, 377 Ostertagia circumcincta, 286 Sarciopharus tectus, host of Leucocyto0 . ostertagi, 288-92 zoon sou-sadiasi, 12 worm burdens in pigs, 321 ;sheep, 313 Sarcolemma of cercaria, 133 Sensory papillae of cercaria, 118, 129-31 Saurocytozoon tupinambi in lizards, 2 of schistosome, 121 Schistocephalus solidus, locations, 192 of schistosomule, 131 Schistosoma haematobium infection Sheep, infection with treatment with hycanthone, 375, 376 Cooperia curticei, 296 mansoni, biochemistry and physioDictyocaulus filaria, 283 logy, 3 7 1 4 Haemonchus contortus, 303 cercaria to schistosomule, 115-1 75 Ntmatodirus spp., 298-300 strain differences in susceptibility Oesophagostomum columbianum, 308 to drugs, 378 Ostertagia circurncincta, 284-7 susceptibility of male worms to “spring rise” of worm burdens in, oxamniquine, 379 3 12-20 tegument, structure, 121-5 Simuliid hosts for Leucocytozoon, 27, (see also under Cercaria and 32, 33 Schistosomule) Sirnuliurn adersi, 33 Schistosomiasis mansoni, chemotherapy anatinum, 33 of, 369-84 angustitarse, 30, 33 Schistosomicidal agents, 370, 374-84 aureurn, 33 Schistosomule, 120 geneculare, 33 characteristics of, 165-70 impukane, 33 collecting vessel for, 153 innocens, 33 collection methods, 157-64 latipes, 33 digestive tract, 145-6 nyasalandicum, 33 ingestion, 119, 156-7 quebecense, 33 enzymes, 154 rugglesi, 33, 44,45 excretory system, 149 venustum, 33 glands, 141-2 vorax, 33 glycocalyx, loss of, 127-8 Sitagra melanocephala, host of Leucopenetration, changes after, 119-21, cytozoon bouffardi, 14 156-7, 373 Skin, ground substance of sensory papillae, 131 cercarial activity against, 151 spines, 129. destruction by schistosomules, 152 surface membrane, changes in, 124-5 -schistosomules. collection of. 157. water intolerance, .166, 170 . 158

43 1

SUBJECT I N D E X

SN 10, 275; phototoxic quinolinemethanol, 98 Sodium, absorption, 235-6 ion gradient for sugar transport, 244 transport, 233 Sodium antimonyl-dimethyl cystein tartrate (Nap), 380-1 Sphilopsyllus cuniculi, reproduction synchronized with host's breeding, 341 Spiruridae, 336 Spring rise in worm numbers in cattle, 320 in sheep, 312-20 Squame, 171 disarticulation by cercarial mucus, 143 Squatarola squatarola, 34 Stickleback, migration of Bunoderina encoliae in, 192 Streptococcus faecalis, effect on bile salts, 223 Stretopelia tranquebarica, host of Leucocytozoon marchouxi, 12 turtur, host of L . turtur, 12 Strigidae, 12 Strigiformes, 12, 19 Strongyloides spp., susceptibility of gilts to, 340 papillosus in calves, colostral transmission, 327 ransomi in piglets, 326 stercalis in dogs, migration, 327 westeri in mares, 328 Strongyloididae, 326-8 Strongyliu equi, permeability of cuticle, 189 Struthio camelus, host of Leucocytozoon struthionis, 7 Struthioformes, 4, 7 Struthioidae, 7 Suckers of cercaria, muscles, 134 Sulphadoxine, 85 -pyrimethamine treatment, 104-5 Sulphalene, 85 gametocytocidal action, 81 and trimethoprim, 1-4 Sulphamethoxazole - trimethoprim (comethoxazole) as antimalarial, 105 effect on P . falciparum, 81 Sulphadiazine, 83, 84-5 Sulphadimethoxine, 84 Sulphonamide-antifol combination. I04 resistance in malaria infection, 74

Sulphonamides, 84, 99, 102 metabolic fate of, 74 Sulphone-antifol combination, 104 Sulphones, 84, 99, 102

T TAC, 370 Taemopyga castonotis, 20 Tapeworm, attachment to intestinal mucosa, 185 Tetracycline in treatment of chloroquine-resistant malaria, 102 Tetrahymena pyriformis effects of antimalarial drugs on, 74,76 77, 81 Tetrainidae, 10 Tetrao urogallus, host of Leucocytozoon mansoni, 10 Thiabendazole, anthelmintic, 286 Thiamine absorption, 240 Thiosemicarbazones, antimalarial, 103 Thiosinamine, inhibition of schistosome egg production, 383 Timalidae, 13 Toxascavis leonina, migratory behaviour, 335 transfuga, 335 Toxocara canis arrested development, 337 colostral transmission and prenatal infection in pups, 332-3 encysted larvae, 331-3 migratory behaviour, 331-2 susceptibility to infection in older male dogs, 340 cati, arrested development and migratory behaviour, 333-4 Trematode adhesion, 187 attachment by suckers, 185 metacercaria, excystation of, 225 migration response, 192 tegument, surface area, I88 Trematodes, digenetic, site selection, 191-2 Triaenophorus noa'dosus, 34 1 Trichinella spiralis, location, 198-9 influence of age and sex of host, 198 Trichonematidae, 307-1 2 Trichostrongylidae, 284-307

432

SUBJECT INDEX

Trichostrongylus deleterious effects on digestive enzymes, 222-3 axei, arrested development, 295-6 spring rise in sheep, 313 colubriformis in sheep, 3 17 pathophysiology, 247 retortaeformis, 295-6, 322 Trilaminate surface membrane (plasmalemma) of cercaria, 123 Trimethoprim, 85, 87, 96 with sulphisoxazole, 88 Trypsin, functions, 221 inactivator, 222 Tubercidin (7-deazaadenosine) antischistosomal effect of, 382 Turdidae, 14 Turdus iliacus, host of Leucocytozoon giovannolai, 14 T.migratorius, 20 mirandae, 14 musicus, 14 pilaris, 14, 20 Turkey, host of Leucocytozoon smithi, 18, 34

U Ubiquinone-8 synthesis by mammalian Plasmodia, 8 1 U.K. 3883, antischistosomal activity, 379 U.K. 4271, oxamniquine, 379 Uncinaria lucasi in fur seal, colostral infection in pups, 325 stenocephala, larvae in milk of bitches, 325 migratory behaviour, 322-3 V Viellonella, effect on bile salts, 223 Villi of intestinal mucosa, 190 pulsation, 186 Vitamins, absorption, 224, 240-1 W Water absorption by epithelial tissues, 245 Woodcock, cells invaded by Leucocytozoon, 31 Wool, cercarial activity against, 150