Veterinary Entomology

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Veterinary Entomology Arthropod Ectoparasites of Veterinary Importance

Richard Wall School of Biological Sciences, The University of Bristol, UK

and

David Shearer School of Veterinary Science, The University of Bristol, UK

I ~n I SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

First edition 1997

© 1997 Springer Science+Business Media Dordrecht Originally published by Chapman & Hali in 1997

ISBN 978-0-412-61510-8 ISBN 978-94-011-5852-7 (eBook) DOI 10.1007/978-94-011-5852-7

Apart from any fair deal ing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright Designs and Patents Act, 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the London address printed on this page.

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A Catalogue record for this book is available from the British Library

Library of Congress Catalog Number: 96-71695

§ Printed on pennanent acid-free text paper, manufactured in accordance with ANSIINISO Z39.48-1992 (Permanence ofPaper).

CONTENTS

Preface xiii Acknowledgements xv

1 The importance and diversity of arthropod ectoparasites 1 1.1 Introduction 2 1.2 Ectoparasite-host relationshi ps 2 1.3 Ectoparasite damage 3 1.4 The evolution of ectoparasite-host relationships 6 1.5 A modern and growing problem 9 1.6 Arthropod structure and function 11

1.6.1 Arthropod segmentation 11 1.6.2 The arthropod exoskeleton 11 1.6.3 Jointed legs 15 1.6.4 Spiracles and gas exchange 16 1.6.5 The arthropod circulatory system 17 1.6.6 The arthropod nervous system 18 1.6.7 Digestion and absorption 18 1.6.8 Arthropod sense organs 20 1.6.9 Arthropod reproduction 22 1.6.10 Arthropod size 23

1.7 Patterns of arthropod development 24 1.7.1 Moulting 24 1.7.2 Simple and complex life cycles 25

1.8 The classification of diversity 27 1.9 The origins of arthropods 29 1.10 Living arthropod groups 31

1.10.1 Arachnids 32 1.10.2 Insects 34 1.10.3 Other living arthropod groups 36

1.11 Arthropod distributions 38 1.12 Further reading 40

2 Mites (Acari) 43 2.1 Introduction 44 2.2 Morphology 44 2.3 Life history 49 2.4 Pathology 49

Vi Contents

2.5 Classification 51 2.5.1 Astigmata 52 2.5.2 Prostigmata 52 2.5.3 Mesostigmata 53

2.6 Recognition of mites of veterinary importance 53 2.6.1 Guide to the sub-orders of Acari 53 2.6.2 Guide to species and families of veterinary

importance 54 2.7 Astigmata 59

2.7.1 Sarcoptidae 59 2.7.2 Psoroptidae 64 2.7.3 Knemidocoptidae 72 2.7.4 Listerophoridae 74 2.7.5 Astigmatid mites of minor veterinary

interest 77 2.8 Prostigmata 78

2.8.1 Demodicidae 78 2.8.2 Cheyletiellidae 80 2.8.3 Trombiculidae 82 2.8.4 Psorergatidae 86 2.8.5 Prostigmatid mites of minor veterinary

interest 88 2.9 Mesostigmata 89

2.9.1 Macronyssidae 89 2.9.2 Dermanyssidae 91 2.9.3 Mesostigmatid mites of minor veterinary

interest 92 2.10 Further reading 93

3 Ticks (Acari) 96 3.1 Introduction 97 3.2 Morphology 97

3.2.1 Ixodidae 97 3.2.2 Argasidae 102

3.3 Life history 103 3.3.1 Ixodidae 103 3.3.2 Argasidae 107

3.4 Pathology 108 3.4.1 Cutaneous effects of tick feeding 108 3.4.2 Systemic effect: vectors of disease 109 3.4.3 Systemic effects: tick paralysis 113 3.4.4 Other systemic effects 114

3.5 Classification 114 3.6 Recognition of ticks of veterinary importance 115 3.7 Ixodidae 117

Contents vii

3.7.1 Ixodes 117 3.7.2 Dermacentor 123 3.7.3 Haemaphysalis 128 3.7.4 Rhipicephalus 130 3.7.5 Boophilus 132 3.7.6 Amblyomma 133 3.7.7 Hyalomma 135

3.8 Argasidae 135 3.8.1 Argas 135 3.8.2 Otobius ·137 3.8.3 Ornithodoros 139

3.9 Further reading 139

4 Adult flies (Diptera) 141 4.1 Introduction 142 4.2 Morphology 142 4.3 Life history 147 4.4 Pathology 149 4.5 Classification 149

4.5.1 Cyclorrhapha 150 4.5.2 Brachycera 150 4.5.3 Nematocera 151

4.6 Recognition of flies of veterinary importance 152 4.6.1 Guide to families of adult Diptera of

veterinary importance 152 4.7 Cyclorrhapha 155

4.7.1 Muscidae 159 4.7.2 Fanniidae 167 4.7.3 Hippoboscidae 169 4.7.4 Glossinidae 171 4.7.5 Cyclorrhaphous flies of minor veterinary

interest 173 4.8 Brachycera 174

4.8.1 Tabanidae 175 4.9 Nematocera 179

4.9.1 Simuliidae 181 4.9.2 Ceratopogonidae 185 4.9.3 Culicidae 188 4.9.4 Psychodidae 191

4.10 Other Diptera of veterinary interest 193 4.10.1 Eye gnats 193

4.11 Further reading 193

viii Contents

5 Myiasis 197 5.1 Introduction 198 5.2 Morphology 199 5.3 Life history 201 5.4 Pathology 202 5.5 Classification 203 5.6 Recognition of dipterous agents of myiasis 204

5.6.1 Guide to the third-stage larvae causing myiasis in domestic animals 204

5.6.2 Guide to genera of adult Diptera causing myiasis in domestic animals 208

5.7 Oestridae 210 5.7.1 Oestrinae 210 5.7.2 Gasterophilinae 215 5.7.3 Hypodermatinae 221 5.7.4 Cuterebrinae 226

5.8 Calliphoridae 229 5.8.1 Cochliomyia 229 5.8.2 Chrysomya 232 5.8.3 Luci/ia 237 5.8.4 Phormia and Protophormia 243 5.8.5 Calliphora 244 5.8.6 Cordylobia 246

5.9 Sarcophagidae 248 5.9.1 Wohlfahrtia 248

5.10 Further reading 250

6 Fleas (Siphonaptera) 254 6.1 Introduction 255 6.2 Morphology 256 6.3 Life history 262 6.4 Pathology 264 6.5 Classification 266 6.6 Recognition of fleas of veterinary importance 266

6.6.1 Guide to the flea species of veterinary importance 266

6.7 Pulicidae 267 6.7.1 ctenocephalides 267 6.7.2 Spi/opsyllus 273 6.7.3 Echidnophaga 273 6.7.4 Pulex 276 6.7.5 Xenopsylla 277

6.8 Ceratophyllidae 278

Contents lX

6.8.1 Ceratophyllus 278 6.8.2 Nosopsyllus 280

6.9 Flea species of minor veterinary interest 281 6.10 Further reading 282

7 Lice (Phthiraptara) 284 7.1 Introduction 285 7.2 Morphology 285 7.3 Life history 288 7.4 Pathology 289 7.5 Classification 291 7.6 Recognition of lice of veterinary importance 292

7.6.1 Guide to the genera of lice of veterinary interest 292

7.7 Amblycera 295 7.7.1 Menoponidae 295 7.7.2 Boopidae 297 7.7.3 Gyropidae 297

7.8 Ischnocera 299 7.8.1 Philopteridae 299 7.8.2 Trichodectidae 302

7.9 Anoplura 306 7.9.1 Haematopinidae 306 7.9.2 Linognathidae 308 7.9.3 Polyplacidae 310

7.10 Further reading 311

8 The control and treatment of ectoparasite infestation 313 8.1 Introduction 314 8.2 Diagnosis of ectoparasite infestation 314

8.2.1 Hair examination 315 8.2.2 Acetate strip examination 315 8.2.3 Superficial skin scraping (epidermal

surface examination) 316 8.2.4 Deep skin scraping (deep epidermal

examination) 316 8.2.5 Collection of free-living ectoparasites 316 8.2.6 Biopsy and histopathology 317

8.3 The chemical control of ectoparasites 318 8.3.1 Ectoparasiticides: early compounds 318 8.3.2 Ectoparasiticides: neurotoxins 318

x Contents

8.3.3 Ectoparasiticides: insect growth regulators 321 8.3.4 Repellents 322 8.3.5 Desiccants 323

8.4 Mode of ectoparasiticide application 323 8.4.1 Topical preparations 323 8.4.2 Systemic preparations 324 8.4.3 Environmental preparations 324

8.5 Problems v-.1th chemical control 325 8.5.1 Poisoning and environmental contamination 325 8.5.2 Resistance 326

8.6 Non-chemical control of ectoparasites 327 8.6.1 Physical control 327 8.6.2 Barriers 328 8.6.3 Biological control 328 8.6.4 Vaccination 329 8.6.5 Trapping 329 8.6.6 Sterile insect technique 330 8.6.7 Modelling and forecasting 330

8.7 Cattle 331 8.7.1 Mites 331 8.7.2 Ticks 334 8.7.3 Flies 335 8.7.4 Myiasis 336 8.7.5 Fleas 338 8.7.6 Lice 339

8.8 Sheep 339 8.8.1 Mites 339 8.8.2 Ticks 343 8.8.3 Flies 344 8.8.4 Myiasis 346 8.8.5 Fleas 348 8.8.6 Lice 348

8.9 Horses 349 8.9.1 Mites 349 8.9.2 Ticks 351 8.9.3 Flies 352 8.9.4 Myiasis 355 8.9.5 Fleas 356 8.9.6 Lice 357

8.10 Pigs 357 8.10.1 Mites 357 8.10.2 Ticks 358 8.10.3 Flies 359 8.10.4 Myiasis 360 8.10.5 Fleas 360 8.10.6 Lice 361

8.11 Goats 8.11.1 Mites 8.11.2 Ticks 8.11.3 Flies 8.11.4 Myiasis 8.11.5 Fleas 8.11.6 Lice

8.12 Dogs 8.12.1 Mites 8.12.2 Ticks 8.12.3 Flies 8.12.4 Myiasis 8.12.5 Fleas 8.12.6 Lice

8.13 Cats 8.13.1 Mites 8.13.2 Ticks 8.13.3 Flies 8.13.4 Myiasis 8.13.5 Fleas 8.13.6 Lice

8.14 Small mammals 8.14.1 Mites 8.14.2 Flies 8.14.3 Myiasis 8.14.4 Fleas 8.14.5 Lice

8.15 Birds 8.15.1 Mites 8.15.2 Ticks 8.15.3 Flies 8.15.4 Myiasis 8.15.5 Fleas 8.15.6 Lice

8.16 Further reading

Glossary Index

Contents xi

361 361 363 364 365 366 366 367 367 371 372 373 374 375 376 376 380 380 381 382 384 384 384 390 390 391 391 392 392 395 395 397 397 398 398

402 421

PREFACE

Although usually treated as unified subject, in many respects the two components of what is broadly described as 'medical and veterinary entomology' are clearly distinct. As is usual, the term entomology is used loosely here to refer to both insects and arachnids. In medical entomology blood-feeding Diptera are of paramount importance, primarily as vectors of pathogenic disease. Most existing textbooks reflect this bias. However, in veterinary entomology ectoparasites such as the mites, fleas or dipteran agents of myiasis assume far greater prominence and the most important effects of their parasitic activity may be mechanical damage, pruritus, blood loss, myiasis, hypersensitivity and dermatitis, in addition to vector-borne pathogenic disease. Ectoparasite infestation of domestic and companion animals, therefore, has clinical consequences necessitating a distinct approach to diagnosis and control.

The aim of this book is to introduce the behaviour, ecology, pathology and control of arthropod ectoparasites of domestic animals to students and practitioners of veterinary medicine, animal husbandry and applied biology. Since the book is directed primarily at the non-entomologist, some simplification of a number of the more involved entomological issues has been deemed necessary to improve the book's logical structure and comprehensibility, and keep its length within limits. A reading list is presented at the end of each chapter to act as a stepping-stone into the specialist literature. In particular, the recognition guides in each chapter need to be used with a degree of caution since they are not comprehensive and, where more detailed identification is required, specialist keys should be consulted. Similarly, in the discussion of the control of ectoparasites, the principles of control and ectoparasiticide use have been emphasized; any attempt to provide a detailed recipe for control might be inappropriate in different parts of the world and would go out of date rapidly. It should be stressed that all insecticides should be used in strict accordance with the manufacturer's local instructions.

This book focuses primarily on the arthropod ectoparasites of the temperate northern hemisphere. To some extent this distinction has been blurred slightly, since so many ectoparasite species have been transported worldwide with humans and domestic animals. But, for the most part, important ectoparasites from tropical and sub-

xiv Preface

tropical habitats have been described only briefly and would require their own volume to do them justice.

ACKNOWLEDGEMENTS

I first would like to thank Shelagh Adam for her patient support and encouragement throughout the writing of this book. Long dinner-table monologues on the vagaries of mite classification and nomenclature would have driven lesser constitutions to despair - or domestic violence. I also would like to express my immense gratitude to my parents, Shirley and Douglas, for the considerable help and guidance over the years, without which the writing of this book would not have possible - literally.

Richard Wall August 1996

I would like to thank my wife Alison for her support and encouragement during the writing of this book. I would also like to thank my colleagues who have encouraged me to pursue an interest in veterinary dermatology and made me realize the need for such a bOOK on veterinary ectoparasites.

David Shearer August 1996

We would like to thank Les Strong, Shelagh Adam, Alison Shearer and Roger Avery who read all, or parts of, the manuscript of this book and helped to eliminate many factual and textual errors. Neverthless, any remaining mistakes are all ours.

R.W. and D.S.