Parasites and Pets: A Veterinary Nursing Guide

By Hany Elsheikha, Ian Wright and John McGarry

This book, primarily focussing on parasitic diseases of cats and dogs, is designed specifically for veterinary nurses and students and adopts an enquiry based approach essential for consolidating knowledge and a deep practical understanding of this important subject. The book goes beyond the conventional discourse of parasitology books, with each chapter addressing questions commonly posed by clients. It is illustrated throughout with colour figures and readers can assess their knowledge and areas for development by completing the end of chapter self-assessment questions.

In this way, the veterinary nurse will be fully equipped to professionally support veterinary surgeons in achieving optimal strategies for management of parasitic diseases of companion animals.

Provides a unique enquiry-based approach to assist veterinary nurses and technicians in gaining essential knowledge and practical understanding of parasites

Contains self-assessment MCQ sections designed to encourage the reader to question their practice, rationales, and the evidence base of parasitology care delivery they provide to patients

Focuses on the dog and cat, the most commonly seen pets

• Language: English
• Publisher: CAB International
• Release date: Jan 31, 2018
• ISBN: 9781786394064

Hany Elsheikha

Hany Elsheikha is an Associate Professor of Veterinary Parasitology at the School of Veterinary Medicine and Science, University of Nottingham. He earned his PhD in Molecular and Evolutionary Parasitology from Michigan State University, where he studied the genetic population structure of the protozoan Sarcocystis neurona, the agent of equine protozoal myeloencephalitis in the Americas. In 2005, he was awarded the National Center for Infectious Diseases (NCID), Centers for Disease Control and Prevention (CDC) Postdoctoral Fellowship. He is the author of more than 250 research and professional articles on parasite pathobiology and control. Hany is the author of one US patent and three textbooks. Also, he is a diplomate of the European Veterinary Parasitology College (EVPC), a member of the European Scientific Counsel of Companion Animal Parasites (ESCCAP) UK & Ireland, a Fellow of the Royal Society of Public Health (RSPH) and a Fellow of the Higher Education Academy (HEA). From 2014 to 2015, Hany was the inaugural Specialty Chief Editor of Parasitology in the journal Frontiers in Veterinary Science . He serves on the Editorial Board of five peer-reviewed journals and as Reviewer of several journals and national and international funding agencies. Since 2007 he has been at the University of Nottingham, where he established the veterinary parasitology curriculum from its inception. Hany is also a veterinarian by training; he obtained a first-class degree with distinction in Veterinary Sciences and MSc in Veterinary Parasitology from Cairo University. His research focuses on host-parasite interaction and anti-parasitic drug discovery.

Book preview

Parasites and Pets: A Veterinary Nursing Guide

Parasites and Pets: A Veterinary Nursing Guide

Hany M. Elsheikha, BVSc, MSc, PhD, FRSPH, PGCHE, FHEA, DipEVPC

University of Nottingham

IanWright, BVS, MSc, MRCVS

Mount Veterinary Practice

JohnMcGarry, MSc, PhD, SFHEA

University of Liverpool

CABI is a trading name of CAB International

© Hany M. Elsheikha, Ian Wright and John McGarry 2018. All rights reserved. No part of this publication may be reproduced in any form or by any means, electronically, mechanically, by photocopying, recording or otherwise, without the prior permission of the copyright owners.

A catalogue record for this book is available from the British Library, London, UK.

Library of Congress Cataloging-in-Publication Data

Names: Elsheikha, Hany, author. | Wright, Ian M., author. | McGarry, John W., author. | C.A.B. International, issuing body.

Title: Parasites and pets : a veterinary nursing guide / Hany M. Elsheikha, Ian Wright, John McGarry.

Description: Wallingford, Oxfordshire ; Boston, MA : CABI, [2018] | Includes bibliographical references and index.

Identifiers: LCCN 2017040051 (print) | LCCN 2017055498 (ebook) | ISBN 9781786394057 (ePDF) | ISBN 9781786394064 (ePub) | ISBN 9781786394040 (pbk. : alk. paper)

Subjects: LCSH: Domestic animals--Parasites. | Veterinary parasitology. | MESH: Parasitic Diseases, Animal--nursing | Pets--parasitology | Animal Technicians | Examination Questions

Classification: LCC SF810.A3 (ebook) | LCC SF810.A3 E47 2018 (print) | NLM SF 810.A3 | DDC 636.089/696--dc23

LC record available at https://lccn.loc.gov/2017040051

ISBN-13: 978 178639 404 0 (paperback)

Commissioning editor: Jill Northcott

Editorial assistant: Emma McCann

Production editor: James Bishop

Typeset by SPi, Pondicherry, India

Printed and bound in the UK by Bell and Bain Ltd, Glasgow

Contents

About the Authors

Preface

1 Introduction to Parasitology

2 Parasites of the Gastrointestinal System

3 Parasites of the Respiratory System

4 Parasites of the Cardiovascular System

5 Parasites of the Skin and Muscles

6 Parasites of the Eye and Nervous System

7 Parasites of the Urogenital System

8 Key Skills for the Veterinary Nurse in Diagnostic Parasitology

9 Parasite Control Clinics

10 Parasite Control and Pet Travel

Glossary

Bibliography

Self-assessment Answers

Index

About the Authors

Hany M. Elsheikha, BVSc, MSc, PhD, FRSPH, PGCHE, FHEA, DipEVPC

Hany is an Associate Professor of Veterinary Parasitology at the School of Veterinary Medicine and Science, University of Nottingham. He earned his PhD in Molecular and Evolutionary Parasitology from Michigan State University, where he studied the genetic population structure of the protozoan Sarcocystis neurona, the agent of equine protozoal myeloencephalitis in the Americas. In 2005, he was awarded the National Center for Infectious Diseases (NCID), Centers for Disease Control and Prevention (CDC) Postdoctoral Fellowship. He is the author of more than 250 research and professional articles on parasite pathobiology and control. Hany is the author of one US patent and three textbooks. Also, he is a diplomate of the European Veterinary Parasitology College (EVPC), a member of the European Scientific Counsel of Companion Animal Parasites (ESCCAP) UK & Ireland, a Fellow of the Royal Society of Public Health (RSPH) and a Fellow of the Higher Education Academy (HEA). From 2014 to 2015, Hany was the inaugural Specialty Chief Editor of Parasitology in the journal Frontiers in Veterinary Science. He serves on the Editorial Board of five peer-reviewed journals and as Reviewer of several journals and national and international funding agencies. Since 2007 he has been at the University of Nottingham, where he established the veterinary parasitology curriculum from its inception. Hany is also a veterinarian by training; he obtained a first-class degree with distinction in Veterinary Sciences and MSc in Veterinary Parasitology from Cairo University. His research focuses on host–parasite interaction and anti-parasitic drug discovery.

Ian Wright, BVS, MSc, MRCVS

Ian is a practising veterinary surgeon and co-owner of the Mount Veterinary Practice in Fleetwood, Lancashire. He has a Master’s degree in Veterinary Parasitology, is head of the European Scientific Counsel of Companion Animal Parasites (ESCCAP) UK & Ireland and guideline director for ESCCAP Europe. Ian has regularly published in peer review journals and is an editorial board member for the Companion Animal journal as well as peer reviewing for journals such as Journal of Small Animal Practice (JSAP), Companion Animal and Veterinary Parasitology. He continues to carry out research in practice, including work on intestinal nematodes and tick-borne diseases.

John McGarry MSc, PhD, SFHEA

John is a Senior Lecturer in Parasitology. He completed his PhD on vector ecology in 1992, at the Liverpool School of Tropical Medicine where he worked for 28 years and completed numerous projects in Africa. He has worked at the Institute of Veterinary Science since 2008. Research interests are the biology and control of parasitic arthropods – principally flies, ticks and mites – as agents of skin infestations and vectors of disease; more recent interests are parasitic lungworms of companion animals, zoonotic helminths of wildlife and forensic entomology, a pathology-related veterinary specialism. He is the author of some 70 publications of international repute.

Preface

This parasitology book is first and foremost designed for the veterinary nurse – the profession’s most valuable asset. Dogs and cats frequently encounter a diverse variety of internal and external parasites; some cause mild symptoms in the pet, others are life threatening, and in some cases human health may be at risk too. Some parasites are very common indeed, such as the roundworm Toxocara canis, and fortunately can be easily and effectively controlled; others, such as certain tick-borne pathogens, may occur sporadically, for example during pet travel, and being perhaps unfamiliar, present a real diagnostic and management challenge for the nurse and practitioner. Nurses are at the very front of the clients’ questions and are asked an astonishing amount about infections and parasites, a familiar enquiry being, ‘Can I catch this from my dog?’ With the nurse in mind, there has long been a need for a reference book that answers such questions posed in this format and which describes common parasites of cats and dogs, the diseases they cause, treatment options and prophylactic measures.

The subject matter of this book focuses primarily on parasitic diseases of dogs and cats in Europe and North America, but many of these are of course a global problem and the information herein is therefore suitable for a wide veterinary audience. The book format is designed for quick reference and will provide essential practical knowledge and training necessary in supporting veterinary surgeons and in providing concise information to clients. The book is composed of ten chapters. Chapter 1 gives a brief overview of parasitology; the following six chapters describe specific parasite problems encountered in small animal practices, and the final three chapters are dedicated to principles of parasite diagnostics and control. Self-assessment questions, answers to which can be found at the end of the book, are formative, to test the reader’s understanding of major topics of parasite life cycles and therapeutics.

Therapeutics is an ever-changing field. Readers of this book are advised to check the most up-to-date product information provided by the manufacturer of each drug to verify the recommended dose, the method and duration of administration and adverse effects. It is the responsibility of attending veterinary professionals to be familiar with the laws governing drugs in their practice areas. Neither the publisher nor the authors assume any liability for any injury and/or damage to persons or property with the use of material(s) and information contained in this book. The mention of trade names or commercial products in this book is solely for the purpose of specific information and does not imply recommendation or endorsement by the publisher or authors.

The book is dedicated to veterinary nurses, students and practitioners. We hope you find this a very useful resource.

Hany M. Elsheikha

Ian Wright

John McGarry

1    Introduction to Parasitology

What is parasitology?

Parasitology is the scientific discipline concerning the study of the biology of parasites and parasitic diseases. By understanding parasites, their behaviour and life cycles, it becomes possible to develop strategies to treat and control parasitic disease.

What is a parasite?

A parasite is an organism that is metabolically and physiologically dependent on another organism (the host). The parasite exploits the host for its development and survival during one or more stages of its life cycle. Some parasites are single-celled (e.g. protozoa) whereas others are multicellular (e.g. worms, arthropods). In many cases, two (or more) parasites can occur in the same host and this phenomenon is known as poly- or hyper-parasitism and the host is said to be co-infected.

How does a parasite get its name?

Scientific nomenclature assigns each parasite two names; the genus name is the first name and the first letter is always capitalized, followed by species name (e.g. Ixodes ricinus) (Fig. 1.1). By convention, both names are italicized. Normally, after a scientific name has been mentioned once, it is abbreviated with the initial of the genus followed by the species name.

Fig. 1.1. Dorsal view of Ixodes ricinus. Also known as the sheep tick, wood tick, or deer tick.

How did the names of parasites originate?

Veterinary professionals and parasitologists must become familiar with both the scientific (i.e. the classification according to Linnaean taxonomy) and common names of parasites (e.g. Toxocara canis, the dog roundworm). Many parasite species have a preferred site of final development (i.e. site of predilection) within the host body. In many cases, the organ of preference provides the common name for the parasite. Examples are the ‘eyeworm’ (Thelazia) and the ‘heartworm’ (Dirofilaria immitis). Some worm species received a common name from their distinctive body shape, such as nematodes of genus Trichuris, known as ‘whip worms’, due to their characteristic whip-like shape. Likewise, the intestinal nematodes of dogs and cats, Ancylostoma spp. and Uncinaria stenocephala, are commonly known as ‘hookworms’.

How big are the parasites?

Parasites range in size from tiny protozoa a few microns in diameter (little more than the size of some bacteria) to very large indeed; for example, the Taenia species tapeworms of dogs can measure several metres in length.

What are the major taxonomic groups of parasites?

In this book we shall cover common parasites in the taxonomic groups: Nematoda (roundworms), Cestoda (tapeworms), Trematoda (flatworms), Arthropoda (insects, acarines) and Protozoa. Nematodes, cestodes and trematodes are collectively known as helminths (worms).

What are the differences between ectoparasites and endoparasites?

Parasites can be divided as above based on sites they infect or infest. Ectoparasites are external and feed or live on the body surface of the host. They may suck the blood (Fig. 1.2) and lymph or feed upon feather, hair, skin and its secretions. Most ectoparasites are arthropods, i.e. invertebrates with jointed legs and hard external skeletons, e.g. lice, ticks, mites, fleas, bugs, flies, and mosquitoes. Endoparasites are internal (i.e. they live inside the host), such as worms (Fig. 1.3) that live in the gut, tissues or other organs.

Fig. 1.2. Mouthparts of the brown dog tick, Rhipicephalus sanguineus. Tick mouthparts are adapted for sucking blood of the animal host and transmission of a wide range of infections.

Fig. 1.3. Adult Toxocara canis roundworms in the small intestine of a dog.

How are facultative and obligatory parasites defined?

Obligatory parasites need a host to complete their life cycle. Facultative parasites can live freely and complete their life cycle without the need of a host; only under certain conditions do they opportunistically enter the body of the host and produce infection, e.g. Strongyloides worms or free-living amoebae.

How can parasites develop resistance to antiparasitic treatment?

Parasiticides are commonly used to treat and control parasitic infections, however they may exert selection pressure that may lead to resistance. Drug resistance is relatively uncommon in companion animals due to wildlife reservoirs of infection that are not exposed to drugs (e.g. cat fleas can feed on many different hosts; the lungworm Angiostrongylus vasorum primarily infects foxes). In the case of some parasites such as the roundworm of dogs, Toxocara canis, encysted larval stages are present in muscle and are therefore protected from anthelmintics in refugia. There have, however, been cases of drug resistance in Dirofilaria immitis (heartworm) and Giardia spp. in North America and evidence of drug resistance exists for intestinal worms in kennelled dogs. Hence, it is important that veterinary professionals treating companion animals for parasites do not become complacent when considering drug resistance.

There are three general strategies by which parasites develop drug resistance. Parasites can: (i) produce an enzyme that destroys the drug; (ii) alter the molecular target so that it is no longer sensitive to the drug; or (iii) prevent access to the target by actively pumping the drug out of the parasite. Once a parasite has chanced upon an effective strategy, the newly acquired or mutated genes that confer that resistance are frequently spread throughout the parasite population.

The problem of drug resistance, at least for parasites of livestock, has been exacerbated by human behaviour. Anthelmintics are also misused in agriculture, where they are commonly employed as food additives to promote the growth of healthy animals. For example, levamisole was commonly added to cattle feed in Europe. Decisions as to when to employ parasiticides are thus a balance between limiting resistance, while not compromising on animal health and minimizing zoonotic risk.

Can parasites affect public health?

Certain parasites are zoonotic, which means they can be transmitted between animals and humans. These infections are always of concern to the public and pet owners, but occupational groups are at risks, not least veterinary surgeons and veterinary nurses, farmers and zoo personnel – indeed anyone who is in frequent contact with domestic, exotic or wild animals. Parasitic zoonoses can be due to endo- or ectoparasites and can cause a variety of mild or serious symptoms in humans – for example, mild as in the case of skin irritation caused by flea bites, or very serious as in multi-organ failure seen in advanced Lyme disease, which is transmitted to people through the bite of a tick usually associated with animals. Because some of the common parasites that infect small animals (e.g. Toxoplasma and Toxocara) also infect humans, especially young children, pregnant women and immuno-suppressed individuals, they pose a public health risk; thus veterinary surgeons and nurses have a responsibility to inform their clients about a parasite’s zoonotic potential. Many of these diseases are associated with faecal contamination of soil, general level of hygiene and food preparation. Some parasites are considered