Trichinella and Trichinosis

Trichinella spiralis

Posterior end of male worm (T. spiralis nativa) by scanning electron microscopy. Courtesy of Drs. ]. R. Lichtenfels and K. D. Murrell, U. S. Department of Agriculture.

Trichinella and Trichinosis

Edited by

William C. Campbell Merck Institutefor Therapeutic Research Rahway, New Jersey

Plenum Press. New York and London

Library of Congress Cataloging in Publication Data

Main entry under title:

Trichinella and trichinosis.

Bibliographv: p. Includes index. 1. Trichinosis. 2. Trichinella spiralis. 1. Campbell, William

1930- . [DNL:vl: 1. Trichinella. 2. Trichinosis. WC 855 T8225]

RCI86.T815T7:l 1983 616.9'654

ISBN-13: 978-1-4613-3580-1 e-ISBN-13: 978-1-4613-3578-8 DOT: 10.1007/978-1-4613-3578-8

© 1983 Plenum Press. New York Softcover reprint of the hardcover I st edition 1983

A Division of Plenum Publishing Corporation 233 Spring Street, New York. N. Y. 10013

All rights reserved

C. (William Cecil),

83-2390

No part of this book may be reproduced, stored in a retrieval system, or transmitted

in any form or by any means, electronic, mechanical, photocopying, microfilming, recording. or otherwise. without written permission from the Publisher

DEDICATED

To Dr. J. Desmond Smyth, who kindled a parasitological fire; to Dr. Arlie C. Todd, who fanned the flames; to Dr. Ashton C. Cuckler, chemotherapist par excellence, who suggested testing a drug against Trichinella and thereby induced an addiction to the affairs of that worm; to the late Dr. S. Emanuel Gould and Dr. Zbigniew Kozar, whose en­couragement kept the addiction from waning; to S.J.C. and the late R.J .C., who made it all possible; and to Mary, Jenifer, Peter, and Betsy, who make it all worthwhile.

Contributors

Lyndia Slayton Blair Merck Institute for Therapeutic Research

Rahway, New Jersey 07065

Graham A. Bullick Department of Physiology and Cell Biology

University of Texas Medical School at Houston Houston, Texas 77025

William C. Campbell Merck Institute for Therapeutic Research

Rahway, New Jersey 07065

Gilbert A. Castro Department of Physiology and Cell Biology

University of Texas Medical School at Houston Houston, Texas 77025

David A. Denham London School of Hygiene and Tropical Medicine

London WCIE 7HT, England

Dickson D. Despommier Division of Tropical Medicine

School of Public Health Columbia University

New York, New York 10032

Terry A. Dick Department of Zoology University of Manitoba

Winnipeg, Manitoba, Canada R3T 2N2

vii

VIII

Anneke Elgersma Rijks Instituut Voor de Volksgezondheid 3720 BA Bilthoven, The Netherlands

Charles W. Kim State University of New York at Stony Brook Stony Brook, Long Island, New York I1794

Jack C. Leighty Dunkirk, Maryland 20754

Inger Ljungstrom Department of Parasitology

National Bacteriological Laboratory S-I052I Stockholm, Sweden

Zbigniew S. Pawlowski Clinic of Parasitic and Tropical Diseases

Medical Academy of Poznan Poznan, Poland

and Parasitic Diseases Programme

W orid Health Organization Geneva 27, Switzerland

E.Joost Ruitenberg Rijks Instituut Voor de Volksgezondheid 3720 BA Bilthoven, The Netherlands

David S. Silberstein Department of Microbiology

Columbia University New York, New York 10032

George L. Stewart Laboratory of Parasitology

Department of Biology University of Texas

Arlington, Texas 76019

Frans van Knapen Rijks Instituut Voor de Volksgezondheid 3720 BA Bilthoven, The Netherlands

Derek Wakelin Department of Zoology

University of Nottingham Nottingham, England

CONTRIBUTORS

CONTRIB UTORS

Norman F. Weatherly Department oj Parasitology and Laboratory Practice

School oj Public Health University oj North Carolina

Chapel Hill, North Carolina 27514

William J. Zimmermann Veterinary Medical Research Institute

Iowa State University Ames, Iowa 50011

IX

Preface

I have cured the Empress of Boolampoo of a Cramp she got in her tongue by eating

Pork and buttered parsnips . ... The Earl of Rochester- 17th Century

As the modern outpouring of biological information continues at ever­increasing pace, two kinds of reviews are needed to keep the torrent in manageable form. The one assumes a working knowledge of the field in question and tries to bring the reader up to date by reporting and assessing the recent developments. The other attempts to assimilate the recent developments into a coherent restatement of the whole subject. This book falls in the latter category.

Trichinella spiralis infection has been in the medical and biological limelight for more than a century, and interest in it continues una­bated-as evidenced by what Norman Stoll called the "perennially exuberant" research on trichinosis. The infection seems to offer some­thing for almost everyone. For the physician, it offers a patient with painful and sometimes fatal disease; for the public-health official, a threat to the commonweal; for the experimental biologist, a life cycle that is unique yet easily and rapidly maintained in the laboratory; for the field ecologist, a symbiont with an affinity for an extraordinary range of wildlife species; for the pork producer, a poorer profit; for the cook, a culinary constraint; and for the diner, a dietary danger. Yet, despite this breadth of interest, and the cascade of new data, the only comprehensive books on the subject in English are those of S.E. Gould, published in 1945 and 1970. Although his work on trichinosis

Xl

XII PREFACE

was virtually an avocation, Dr. Gould's passion for the subject enabled him to produce landmark treatises. His 1970 volume, Trichinosis in Man and Animals, with contributions from many authors, remains a treasure­house of information. But the past dozen years have brought major new findings in all aspects of trichinosis, and it is time for another stock-taking. This volume offers a fresh synthesis of old and new information, and it is hoped that the work will serve as a succinct yet comprehensive source of information on Trichinella as parasite and pathogen.

The use of the term trichinosis, rather than trichinellosis, will dismay some readers. Adoption of trichinellosis would have been baffling to others. It can be argued that as Trichinella was gradually becoming accepted as the correct name for the nematode genus Trichina, so trichinosis should have become superseded by trichinellosis. But trichinosis had already spread from the technical language to the vernacular, and, as in the case of malaria and coccidiosis, a new lexicon was not needed to clarify what was already perfectly clear to the scientist and layman alike. (In 1911, Ambrose Bierce's The Devil's Dictionary contained the entry: Trichinosis, n. The pig's reply to proponents of porcophagy.) We have two defensible words for disease caused by Trichinella, and with some misgiving we have chosen to stick with the one that is shorter and more venerable.

W.c.c.

Acknowledgments

The Editor is greatly indebted to the contributing authors for their fine cooperation. He especially thanks Dr. D.D. Despommier, Ms. L.S. Blair, Dr. D.A. Denham, and Dr. C.W. Kim for their wise aQd generous counsel throughout the planning and execution of the volume. Thanks are extended to Mrs. June Wood for typing several portions of the text, and to Mr. K. Jensen and Mr. L. Goldes of Plenum Press for their expert production of the book.

Xlll

Contents

CHAPTER 1

Historical Introduction WILLIAM C. CAMPBELL

1. Prologue: Ghosts of Christmas Past and Christmas Present. . . . . . . . . . . 1 2. A Worm Discovered (1835) ........................................... 3 3. A Nematode Life Cycle Discovered (1835-1860)...................... 8 4. From Zoological Curiosity to Lethal Pathogen (1860-1900)........... 15 5. Consequences (Politics and Parasites). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6. The Recent Past. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

CHAPTER 2

Species, and Infraspecific Variation TERRY A. DICK

1. Historical Perspective.................................................. 31 2. A Working Definition of Species. .. . . . . . . . . .. .. .. .. .. ...... .. .. ... .. .. 33 3. Terminology.......................................................... 36 4. Distribution of Isolates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5. Criteria for Species and Isolates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.1. Genetic Criteria................................................. 41 5.2. Morphological Criteria.......................................... 45 5.3. Biochemical and Immunological Criteria. . . . . . . . . . . . . . . . . . . . . . . . 52 5.4. Sensitivity to Drug Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 5.5. Effect of Host on Reproductive-Capacity Index.. . . . . . . . . . . . . . . . 55 5.6. Other Biological Characteristics.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

xv

XVI CONTENTS

6. Trichinella spiralis var. pseudospiralis-an Enigma. . . . . . . . . . . . . . . . . . . . . . . 63 7. Speciation in Trichinella................................................ 64 8. Future Considerations................................................. 68 References. . . . . . . . . . . . . . .. . . . . . . .. . .. .. . .. .. .. .. .. ............ .... ........ 70

CHAPTER 3

Biology DICKSON D. DESPOMMIER

1. Introduction........................................................... 75 2. Ingestion of the Infective First-Stage Larva. . . . . . . . . . . . . . . . . . . . . . . . . . . 79 3. Digestion of Host Tissues away from the Infective First-Stage Larva 80 4. Intramulticellular Enteral Niche....................................... 81

4.1. Entrance of the Infective First-Stage Larva.. .. ....... .. .... .. .. . 81 4.2. Molting and Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 4.3. Mating........................................................... 117 4.4. Fecundity........................................................ 124

5. Intracellular Parenteral Niche. .. .. ... ... . . ... . ........... .... .... .... . 130 5.1. Migration of the First-Stage Larva to the Niche................. 130 5.2. Entrance of the Migratory First-Stage Larva. . . . . . . . . . . . . . . . . . . . 134 5.3. Growth and Development. . . . .. .. . ... . .... ....... .. .. .... .. .... . 136 5.4. Mature Nurse Cell-Infective First-Stage Larva Complex........ 140

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

CHAPTER 4

Biochemistry GEORGE L. STEWART

1. Introduction........................................................... 153 2. Carbohydrates and Carbohydrate Metabolism......................... 154

2.1. Adult Worms.................................................... 154 2.2. Muscle Larvae.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

3. Respiration............................................................ 159 3.1. Adult Worms.................................................... 159 3.2. Muscle Larvae................................................... 160

4. Lipids and Lipid Metabolism.......................................... 162 4.1. Adult Worms .................................................... 162 4.2. Muscle Larvae................................................... 162

5. Nucleic Acids and Nucleic Acid Metabolism: Muscle Larvae. .. .. .. ... 164 6. Proteins and Protein Metabolism: Muscle Larvae and Adult Worms.. 165 7. Nutrition.............................................................. 167

7.1. Adult Worms.................................................... 167 7.2. Muscle Larvae................................................... 168

References ............................................. , ., .. ....... .... ... 169

CONTENTS

CHAPTER 5

Anatomical Pathology NORMAN F. WEATHERLY

xvii

1. Introduction........................................................... 173 2. Gastrointestinal Tract................................................. 174

2.1. Gross Changes................................................... 175 2.2. Microscopic Changes............................................ 177

3. Striated Muscle........................................................ 192 3.1. Gross Changes................................................... 193 3.2. Microscopic Changes............................................ 193 3.3. Encapsulation.................................. .. .. .. . .. .. .. .. .. 195 3.4. Calcification.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

4. Other Organs Involved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 4.1. Heart..................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 4.2. Liver............................................................ 201 4.3. Spleen.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 4.4. Kidneys.......................................................... 202 4.5. Eyes............ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 4.6. Lungs.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 4.7. Central Nervous System......................................... 204 4.8. Bone Marrow.................................................... 204 4.9. Other Locations................................................. 204

References. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. .. .. .. ... . ....... ... ........ 205

CHAPTER 6

Pathophysiology of the Gastrointestinal Phase GILBERT A. CASTRO and GRAHAM R. BULLICK

1. Format of This Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 2. Gastrointestinal Symptoms............................................ 210 3. Morphological Changes ............................................... 211

3.1. Macroscopic........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 3.2. Histological...................................................... 212

4. Physiological Changes................................................. 217 4.1. Epithelium-Related.............................................. 217 4.2. Smooth-Muscle-Related.......................................... 225

5. Bases for Functional Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 5.1. Direct Action of Parasite. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 5.2. Influence of Lamina Propria. . .. .. .. .. . ....... .... .. ... .... ..... 229 5.3. Endocrine Disturbances......................................... 231

6. Host-Parasite Interrelationships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 7. Relationships between Pathophysiology and Symptoms............... 232 8. Summary.............................................................. 234 References. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . .. .... .... .. .... .... .. 235

XVlll

CHAPTER 7

Pathophysiology of the Muscle Phase GEORGE L. STEWART

CONTENTS

1. Introduction........................................................... 241 2. Parasite-Induced Modifications in Host Striated Skeletal Muscle. . . . . . 242

2.1. Alterations Induced in the Host Myofiber during Contact and Entry by the Newborn First-Stage Larva. .... .... .. .. ..... ...... 242

2.2. Alterations in Host Muscle during Growth and Development of the Muscle Larva. . .. . .. .. . .. .. . .. .... . .. .. .. .. .. .. .... .. ..... ... 242

2.3. Mature Nurse Cell. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 2.4. Hypothesis: A Possible Mechanism by Which the Parasite

Initiates Redifferentiation in the Host Myofiber. . . . . . . . . . . . . . . . . 254 2.5. Benefits Derived by the Muscle Larva from Pathophysiological

Alterations in Host Muscle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 256 3. Cardiopathophysiology in Trichinosis................................. 259 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

CHAPTER 8

The Immune Response DEREK WAKELIN and DAVID A. DENHAM

1. Introduction........................................................... 265 2. Immunity and the Intestinal Phase. . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . 266

2.1. Immunity against Adult Worms in Primary Infections. . . . . . . . .. 266 2.2. Immunity against Adult Worms in Reinfections................. 279 2.3. Immunity against Preadult Stages-Rapid Expulsion...... ..... 281

3. Immunity and Newborn Larvae....................................... 285 3.1. Active Immunity in Mice and Rats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 3.2. Passive Immunity in Mice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 288 3.3. Effects of Cells and Serum Components in Vitro.......... . . . . .. 289

4. Genetic Influences on Immunity to Trichinella. . . . . . . . . . . . . . . . . . . . . . . .. 290 5. Stage Specificity of the Immune Response. . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

5.1. "Dual-Antibody" Hypothesis of Oliver-Gonzalez... .... ..... .. .. 294 5.2. Immunological Evidence........................................ 295 5.3. Parasitological Evidence......................................... 298 5.4. A Revision of the Dual-Antibody Hypothesis.. .. .. .... .... ...... 299

References. . .. . .. .. . . . . . . . . . . . .. .. . .. .. . .. .. ... .. .. ............ ..... .. .... 300

CHAPTER 9

Antigens DAVID S. SILBERSTEIN

1. Introduction........................................................... 309 2. Source of Antigens.................................................... 312

2.1. Cuticular Antigens .............................................. 312

CONTENTS XIX

2.2. Excretory-Secretory Antigens................................... 314 2.3. Somatic Antigens................................................ 320

3. Enumeration, Isolation, and Characterization of Antigens. . . . . . . . . . . . 321 4. Concluding Remarks.................................................. 328 References. . .. . . .. . . . . . . . . . . . . . . .. . . .. .. .. ..... .... ... . ..... .. .. .... .... .. 330

CHAPTER 10

Chemotherapy WILLIAM C. CAMPBELL and DAVID A. DENHAM

1. Introduction........................................................... 335 2. Experimental Chemotherapy.......................................... 336

2.1. Methods.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 2.2. Drug Efficacy.................................................... 340

3. Clinical Chemotherapy................................................ 358 3.1. Clinical Prophylaxis ............................................. 359 3.2. Clinical Therapy (Treatment of Patent Infections) . . . . . . . . . . . . . . 359

References. . .. . . .. . . . . . . . . . . . . .. .. . . .. . . ... .... .. .. ... . ............ ....... 361

CHAPTER II

Clinical Aspects in Man ZBIGNIEW S. PAWLOWSKI

1. Introduction........................................................... 367 2. Infection and Disease ................................................. , 368

2.1. Proportion of Symptomatic and Asymptomatic Cases in Trichinosis ...................................................... 368

2.2. Course of Trichinosis. . .. . .. . .. .. .. .. .. .. . ... .... .. ... ... ........ 369 2.3. Severity of Trichinosis. . ..... .. . .... .... .. .. .... ... .. ... .... ..... 372 2.4. Factors That Influence the Severity of Trichinosis.. ............ 374

3. Symptoms, Signs, and Clinical Pathology. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 375 3.1. Abdominal Syndrome........................................... 376 3.2. General Trichinosis Syndrome. .. ............ .... ... ............ 377 3.3. Signs of Allergic Vasculitis.............................. .... .... 377 3.4. Symptoms and Signs Associated with Muscle Tissue. . . . . . . . . . .. 379 3.5. Signs of Metabolic Disorders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 3.6. Complications of Trichinosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 3.7. Pathology in Laboratory Tests................................... 385

4. Diagnosis.............................................................. 387 4.1. Clinical History-Taking.......................................... 389 4.2. Physical Examination............................................ 391 4.3. Paraclinical Tests................................................ 391 4.4. Finding the Parasite. . .. .. .. . .. . .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .. .. 392 4.5. Differential Diagnosis of Trichinosis .. . . . . . . . . . . . . . . . . . . . . . . . . . . 393

5. Management and Treatment.......................................... 394 5.1. Treatment of the Intestinal Infection ........................... 394

xx CONTENTS

5.2. Acute Severe Trichinosis.. ..... .. . .... .. ....... .... ....... ...... 395 5.3. Moderate or Mild Trichinosis.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 396 5.4. Late and Convalescent Phases of Trichinosis. . . . . . . . . . . . . . . . . . . . 396 5.5. Trichinosis in Children, Pregnant and Lactating Women, and

Immunosuppressed Patients.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398

CHAPTER 12

Immunodiagnosis in Man INGER LJUNGSTROM

1. Introduction........................................................... 403 2. Immunodiagnostic Methods........................................... 404

2.1. Parasite Antigens................................................ 404 2.2. Indirect Immunofluorescence.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405 2.3. Passive Hemagglutination....................................... 407 2.4. Enzyme-Linked Immunosorbent Assay.. .. .. .. .. .. .. .. .. ... .. ... 408 2.5. Counterimmunoelectrophoresis................................. 410 2.6. Other Serological Methods. .. ... .... ..... .. .... .. .. .. .. ......... 411 2.7. Skin Tests....................................................... 412

3. Evaluation and Recommendation...................................... 413 4. Conclusions............................................................ 415 5. Protocols for Indirect Immunofluorescence and Enzyme-Linked

Immunosorbent Assay................................................. 416 5.1. Indirect Immunofluorescence.. .. .. ..... .... .... .. .. ..... .. ..... 416 5.2. Enzyme-Linked Immunosorbent Assay.......................... 418

References .......... " . .. . . . . . .. .. . .. .. . .. .. .. . .. .. .... .... ..... .... .. .. .. 420

CHAPTER 13

Epidemiology I: Modes of Transmission WILLIAM C. CAMPBELL

1. Introduction........................................................... 425 2. Sylvatic Cycle.......................................................... 426 3. Domestic Cycle........................................................ 431 4. Special Epidemiological Circumstances ....... '" ., .. ........ .......... 434 5. Susceptible Host Species.. . . ... .. . .. ... .. .. .. ..... ........ .. .. ..... .... 436 References. . .. . .. .. . .. . .. .. . . . .. ... .. .. . .. ... . . .. .. ................. .. .... 442

CHAPTER 14

Epidemiology II: Geographic Distribution and Prevalence CHARLES W. KIM

1. Introduction........................................................... 445 2. North America........................................................ 446

CONTENTS xxi

2.1. Canada and Alaska.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 446 2.2. Greenland...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449 2.3. United States.................................................... 450 2.4. Latin America................................................... 457

3. Europe................................................................ 460 3.1. British Isles...................................................... 460 3.2. Germany........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . 462 3.3. Austria..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463 3.4. Switzerland. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 463 3.5. The Netherlands................................................ 464 3.6. Belgium................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465 3.7. France........................................................... 465 3.8. Spain... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466 3.9. Portugal .......... , . . . .. . .. .. . .. . . .. . .. .. .. . .. .. .. .. .. .. . .... .. .. 467 3.10. Italy............................................................. 468 3.11. Greece........................................................... 468

4. Scandinavia............................................................ 469 4.1. Norway .......................................................... 469 4.2. Sweden.......................................................... 470 4.3. Denmark........................................................ 471 4.4. Finland .......................................................... 471

5. Eastern Europe........................................................ 472 5.1. Poland........................................................... 472 5.2. Czechoslovakia.................................................. 474 5.3. Hungary......................................................... 475 5.4. Romania......................................................... 476 5.5. yugoslavia....................................................... 477 5.6. Bulgaria......................................................... 478

6. Union of Soviet Socialist Republics.................................... 479 7. Asia................................................................... 482

7.l. Middle East...................................................... 482 7.2. Southeast Asia................................................... 484 7.3. Far East......................................................... 485

8. Africa................................................................. 486 9. Australia, New Zealand, and Pacific Islands.. .. .. .. .. .. ... .... .... .... 488 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489

CHAPTER 15

Control I: Public-Health Aspects (with Special Reference to the United States) JACK C. LEIGHTY

l. Introduction........................................................... 501 2. Mechanisms of Control.. . . .. .. . . . . .. .. .. .. .. .... ........ .. ... .... ..... 502

2.l. Prevention of Swine Infections.................................. 502 2.2. Detection of Infected Swine.. . .... .... .. .. .... ....... .. .... ..... 503

XXII CONTENTS

2.3. Rendering Infected Pork Noninfective .... .... .... .. ............ 505 2.4. Game Foods..................................................... 507

3. Measures Adopted in the United States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507 3.1. Control of Garbage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508 3.2. Regulation of Commercial Pork Products... .... ........ ..... ... 509 3.3. Game Foods..................................................... 510 3.4. Education....................................................... 510 3.5. The Future...................................................... 511

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511

CHAPTER 16

Control II: Surveillance in Swine and Other Animals by Muscle Examination WILLIAM J. ZIMMERMANN

1. Introduction........................................................... 515 1.1. General Methods and Uses...................................... 515 1.2. Criteria for Use................................................. 516

2. Trichinoscopic Method................................................ 516 2.1. Use.............................................................. 516 2.2. Procedure for Swine Diagnosis. . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . . 517 2.3. Drawbacks....................................................... 518 2.4. Other Uses...................................................... 519

3. Basic Digestion Method ............................................... 520 3.1. Basic Procedure................................................. 520 3.2. Modifications.................................................... 520 3.3. Advantages and Disadvantages.................................. 521

4. Pooled Digestion Methods............................................. 521 4.1. Pooled-Sample Method: Procedure.............................. 521 4.2. Stomacher Method: Procedure.................................. 522 4.3. Other Modifications............................................. 524

5. Other Direct Diagnostic Methods. .. ... .. .. .. . .... .... .... .. .. ....... .. 525 5.1. Mechanical Disintegration Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525 5.2. Microscopic Section (Biopsy Method) ..................... ,. .. ... 525 5.3. Xenodiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525

6. Summary.............................................................. 526 References.. . . . . . . . . . . . . . .. . . . . . .. . .. . . . .. .. .. .. .. ..... ........ .. .. ..... .. 526

CHAPTER 17

Control III: Surveillance in Swine by Immunodiagnostic Methods E. JOOST RUITENBERG, FRANS V AN KNAPEN, and ANNEKE ELGERSMA

1. Introduction........................................................... 529 2. Serological Methods................................................... 530

2.1. Complement-Fixation Test...................................... 530

CONTENTS

2.2. Particle-Agglutination Methods ................................. . 2.3. Indirect Immunofluorescence Test. ............................ . 2.4. Enzyme Immunoassays ......................................... . 2.5. Radioimmunoassay ............................................. .

3. Sensitivity and Specificity ............................................. . 4. Antigen Preparation and Purification ................................ . 5. Evaluation of Serological Methods in Various Geographic Areas ..... .

5.1. Evaluation of the Enzyme-Linked Immunosorbent Assay in the United States ................................................... .

5.2. Evaluation of the Enzyme-Linked Immunosorbent Assay in European Countries ............................................ .

6. Mechanization ........................................................ . 6.1. Mechanized System for the Macro-Enzyme-Linked

Immunosorbent Assay .......................................... . 6.2. Mechanized System for the Micro-Enzyme-Linked

Immunosorbent Assay .......................................... . 7. Surveillance by Serological Methods .................................. .

7.1. Inspection at the Slaughterhouse ............................... . 7.2. Inspection at the Farm ........................................ .. 7.3. Individual vs. Population Control ........... , .................. . 7.4. Legislation ..................................................... ..

8. Concluding Remarks ................................................. . References ............................................................... .

APPENDIX 1

Synopsis of Morphology DICKSON D. DESPOMMIER and WILLIAM C. CAMPBELL

XXIII

530 531 533 537 538 538 540

540

540 541

542

543 544 545 545 546 546 547 547

1. Introduction........................................................... 551 2. Morphology of the Adult Male. .. . . . . .. .. .. .. . . .. .. .. .. .. . .. . .. .. .. ... 551 3. Morphology of the Adult Female. .. . . . .. .. .. .. .. .. .. .. ... ... .. .. .... .. 554 4. Morphology of the Infective First-Stage Larva. . . . . . . . . . . . . . . . . . . . . . . . 558 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558

APPENDIX 2

Laboratory Techniques LYNDIA SLAYTON BLAIR

Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569

Index.................................................................... 571