Rapid Review of Small Exotic Animal Medicine & Husbandry

321 Pages·2008·27.27 MB·English

by  Neil A Forbes

Rapid Review of
Exotic Animal
Medicine and
Husbandry
Pet Mammals, Birds, Reptiles, Amphibians, and Fish
Karen L Rosenthal
MS DVM DiplAVBP
University of Pennsylvania, Philadelphia, Pennsylvania, USA
Neil A Forbes
BVetMed CBiol MIBiol RFP DipECAMS FRCVS
Great Western Referrals, Swindon, Wiltshire, UK
Fredric L Frye
BSc, DVM, MSc, CBiol, FIBiol, FRSM
Cloverdale, California, USA
Gregory A Lewbart
MS VMD DiplACZM
North Carolina State University, Raleigh, North Carolina, USA
Manson Publishing/The Veterinary Press
Copyright © 2008 Manson Publishing Ltd
ISBN: 978-1-84076-055-2
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Contents
Preface 4
Acknowledgement 4
Abbreviations 5
Small Mammals 7
Karen L Rosenthal
Classification of cases by species 7
Introduction 8
English and Latin names 10
Cases 11
Summary questions and answers 82
Bibliography 84
Birds 85
Neil A Forbes
Classification of cases by species 85
Introduction 86
English and Latin names 88
Cases 90
Summary questions and answers 146
Bibliography 149
Reptiles and Amphibians 151
Fredric L Frye
Classification of cases by species 151
Introduction 152
English and Latin names 154
Cases 156
Summary questions and answers 233
Bibliography 235
Ornamental Fish 237
Gregory A Lewbart
Classification of cases by species 237
Introduction 238
English and Latin names 242
Cases 244
Summary questions and answers 303
Bibliography 306
Appendix 307
Conversion factors for converting SI units to Old units 307
Normal values: small mammals 308
Normal values: birds 309
Index 311
Preface
Exotic animal medicine has evolved over the last two manner that imitated practice. There was a history, some
decades. Although gradual, the changes are profound. examinations findings, and a patient with a lesion that
These changes are actually accelerated by the expectations could be illustrated. In many of these cases the reader
of our clients, not necessarily by wide-ranging discoveries was given the same options he or she would have in
at our centers of learning. In fact, centers for research practice. What are the differentials? How can they be
may lag behind the day-to-day cases we see in practice. As ruled out? How should the patient be treated? And the
veterinarians, it is important for us to understand and answers were just over the page, allowing for almost
recognize both the common and uncommon cases that instantaneous learning.
enter our examination rooms. It is hoped that what This format was very well received. So well received in
follows in this book will help in this process. fact that demand dictated a book for each group of
Two decades ago veterinarians probably knew more exotic animals seen in practice. Two decades ago, this
about their avian patients than they did about their reptile was fine. However, this is no longer fine. The trend
or amphibian ones. And if veterinarians wanted to among organized veterinary exotic animal associations
become familiar with the diseases of one particular group and journals is to consolidate rather than split. Many
of exotic patients, they usually concentrated on the group association meetings include more than one group of
where the most information could be found, which exotic animal presentations. Many colleagues do not see
tended to be birds. Also, some veterinarians were content just avian or reptile patients, but wish to see all exotic
to be known as the ‘doctor down the road’ who could patients. Clients would prefer to visit a veterinarian who
handle, take blood from, and treat your macaw or iguana. can deal with all their exotic patients rather than visit
It was difficult to find concise, helpful information on just someone who specializes in birds and someone else who
one group of exotic patients, but to find such information specializes in reptiles. Sadly, our university system, in
on more than one group was almost impossible. In fact, it general, still lacks the resources to teach many of their
was impossible. Veterinarians who treated birds were veterinary students about exotic animal patients. For
usually content knowing all they could about birds. most newly graduated veterinarians, the ability to help
Reptile patients were referred around the corner (if they these patients is a ‘live and learn’ process. This is not
were lucky), but it could be many miles around the ideal for the patients and can be discouraging to
corner if the nearest reptile colleague was not close by. fledgling veterinarians. This book was born in an effort
Over the last two decades the collective clinical to revive the successful format followed in the self-
experience in exotic animal medicine and surgery from assessment series and to satisfy the appetite of all
colleagues throughout the world has led to a better veterinarians who wish to learn more about exotic
understanding of health and disease in such patients. patients. We hope these pages will prove useful in the
Numerous texts in a variety of formats have been treatment of these wonderful patients.
published to bring this information to a greater
audience, so veterinarians who have not had the Karen Rosenthal
opportunity to work with exotic animals can catch up Neil Forbes
with those who have. The self-assessment series of titles Fred Frye
from which this book has evolved presented cases in a Greg Lewbart
Acknowledgement
In the course of writing and editing a book, there are needs to be acknowledged, and that is Peter Beynon.
numerous people, not apparent to the readership, Without Peter’s help, encouragement, and tireless
without whom there would be no book. It could take editing, there would be mostly blank pages in this
another volume just to thank all of these people. But book. Peter, we cannot thank you enough for making
for this project there is one person in particular who this project a reality.
4
Abbreviations
ACE angiotensin converting enzyme KCl potassium chloride
ACTH adrenocorticotropic hormone KHV koi herpesvirus
AFA ethyl alcohol, formalin, and acetic acid KOH potassium hydroxide
(solution) LDH lactic acid dehydrogenase
ALT (SGPT) alanine aminotransferase MIC minimum inhibitory concentration
AP (SAP) alkaline phosphatase MMC melanomacrophage center
AST (SGOT) aspartate aminotransferase MRI magnetic resonance imaging
BUN blood urea nitrogen NaCl sodium chloride
Ca calcium NSAID nonsteroidal anitiinflammatory drug
CBC complete blood count OIE World Organisation for Animal Health
CDV canine distemper virus OTC over the counter
CHV1 cyprinid herpesvirus 1 PBFD psittacine beak and feather disease
CNS central nervous system PCR polymerase chain reaction
CPK (CK) creatine phosphokinase PCV packed cell volume
CT computed tomography p/o per os
DEFRA Department for Environment, Food and PO4 phosphate
Rural Affairs (UK) p.p.t. parts per thousand
DMSA dimercaptosuccinic acid p.p.m. parts per million
DNA deoxyribonucleic acid PTH parathyroid hormone
DTM dermatophyte test medium PVC polyvinyl chloride (piping)
ECG electrocardiogram RBC red blood cell
EDTA ethylenediamine tetra-acetic acid RNA ribonucleic acid
ELISA enzyme-linked immunosorbent assay s/c subcutaneous/subcutaneously
GGT gamma glutamyltransferase SADV sialodacryoadenitis virus
GI gastrointestinal SBI swim bladder inflammation (virus)
HLLE head and lateral line erosion SCUD septicemic cutaneous ulcerative disease
HPOA hypertrophic pulmonary osteoarthropathy SG specific gravity
IFA immunofluorescence assay SVC spring viremia of carp (virus)
i/c intracoelomic TP total protein
i/m intramuscular/intramuscularly UV ultraviolet
i/o intraosseous/intraosseously WBC white blood cell
i/v intravenous/intravenously
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Section 1
SMALL
MAMMALS
Karen L Rosenthal
Classification of cases by species
Rabbits 1 to 40
Ferrets 41 to 56
Guinea pigs 57 to 66
Hamsters 67 to 73
Hedgehogs 74 to 81
Chinchillas 82 to 86
Rats 87 to 93
Mice 94 to 95
Squirrels 96 to 97
Gerbil 98
7
Introduction
Exotic animal medicine is, in my biased opinion, the there are always owners who won’t pay for the care their
most exciting area of veterinary medicine today. It is dogs and cats need. Over the last two decades a ‘tipping
stimulating, it is dynamic, and it is demanding. The point’ has been reached and there are now owners of
challenge can quickly turn to frustration if the exotic pets who want the same level of veterinary care for
knowledge that is needed to work with these animals is these pets as is provided for other companion animals.
not immediately available. When we think of the more We can take this further and say that there are owners
traditional areas of companion animal veterinary who want not only equal care to dogs and cats, but the
medicine, the information we require is usually right at same level as is given to people. Some owners do not
our fingertips in the form of books, journals, review think twice when explained the benefits of a CT scan;
ar ticles, or even calls to colleagues. The basic they do not ask how much but instead ask when it can
information for more traditional pets is taught to us at be done. Owners have pushed veterinarians to give a
veterinary school and the diseases, diagnostics, and very high level of care, which in turn has propelled our
treatments become second nature while in practice. knowledge of how to diagnose and treat these pets as
When asked by a new dog owner the lifespan of their never before.
pet, we do not need to consult a colleague halfway across How has our knowledge of these animals increased?
the world to answer that question, but when a Some of it is through research. Research on the diseases
prospective new owner of a small mammal asks which of of small mammals is mostly limited to their use as animal
the common small mammal pets lives the longest, how models or laboratory subjects. The information garnered
many of us can rattle off the lifespan of chinchillas, from these studies is extrapolated to pets. Realistically,
ferrets, guinea pigs, or hedgehogs. not many of these studies are relevant to the information
It is therefore apparent that even the basic knowledge we need to treat conditions seen in pet small mammals.
of these exotic pets can be patchy at best. For many of Due to the lack of a large, profitable market, there is
us, the curriculum in veterinary school did not include little research into drug treatments and nutrition of these
the majority of these pets and what we learned was pets. Some of the veterinary care of small mammals is
probably outdated and wrong. When asked a question in extrapolated from the way we treat dogs and cats. This
the examination room, often there is no knowledge base carries over well with carnivores such as ferrets, but can
to fall back on, and no frame of reference. We need fall short when working with herbivores. The database of
information. This is what this section hopes to knowledge about herbivores and other small mammals,
accomplish, so that armed with the basics you will feel and much of the information contained within this book,
comfortable with these different pets and also have a has over the past three decades come mainly from
source of information to enable you to go further and to anecdotal information.
diagnose and treat these great pets. Although the techniques used in small mammals are
Exotic animal medicine has grown by leaps and bounds. similar to those used in other pets, it is extremely
In the 1970s and 1980s these were the bizarre animals important to understand the significance these methods
brought in by eccentric owners. However, in the last two make in their veterinary care. The four aspects of
decades many of these species have become as popular in veterinary care that need to be emphasized are history
some areas of the world as dogs and cats. For example, in gathering techniques, examination techniques,
the UK by the second decade of this century, rabbits may diagnostics, and special instrumentation. Many of the
surpass other pets to become the most popular house pet. diseases in small mammal medicine concern poor
Would anyone have imagined that in 1970? But then again, husbandry techniques, so it is vital that the veterinarian
would any veterinarian treating horses and cattle in 1900 who sees small mammals is well informed. Develop a fill-
believe that people now pay money for their dogs and cats in form so that you never miss a question. By not asking
to be treated. Everything is relative. the correct questions, you may totally miss the diagnosis.
Veterinarians want to do their best for all of their In small mammals, possibly the most important
patients, and owners want the best care for their pets. diagnostic test is the history form. Description of diet
The difficulty with exotic pets is that our knowledge and housing are two of the most important aspects of
changes so rapidly that it is difficult to keep up with the history taking. Where has the pet been, which animals
best diagnostic and treatment options. Sometimes, new has it been exposed to, and where did the pet come from
diseases appear that are regional and it is not easy to find are some of the other important questions to ask.
out this information. However, it is no longer acceptable Examination techniques are very similar to those carried
to say that no one knows about rabbit dental disease or out in dogs and cats, but there are some aspects that are
that it is impossible to treat adrenal gland disease in particularly important in small mammal examination. In
ferrets. It is no longer acceptable to categorize these rabbits it is always important to check the teeth for
animals as second-class pets. There will always be owners points, to ausculate the abdomen for gut sounds, and to
who won’t pay for the care these pets need, but then examine the perineum for stool impactions. In ferrets it
8
Small Mammals
is always important to note changes to the normal hair now to at least allow the owner to understand why their
coat. Diagnostic tests are also similar to those performed rabbit has become sick on a pelleted only diet. It is likely
in dogs and cats, but the clinician needs to be aware of that dental problems, at least partially, exist in rabbits
the size limitations and that many tests are not backed due to the lack of proper fiber in the diet. This lack of
up with published studies. Also, it is important that the fiber is directly related to the pelleted diet; specifically,
specialized instruments necessary to work with these the pelleted diet most owners find at the pet store.
animals are present in the veterinary practice (i.e. small Although the connection between a pelleted diet and
needles and syringes, gram scales, and small surgical dental disease is supposed, it is very clear that the
instruments). Finally, medications in dosage forms and traditional, low-fiber, pellet only diet clearly contributes
volumes specifically designed for small mammals must to poor cecal health. The lack of fiber, the high caloric
also be available. content, and the high carbohydrate content of food can
The advances in rabbit medicine are probably as lead directly to a change in the normal cecal contents.
significant as in any species over the last two decades. The bacterial population changes, the entire milieu of
Although we may not have all the answers, we the cecum changes, and gastrointestinal disease develops.
understand the pathophysiology of disease in these pets Poorly formed stools, ileus, and eventually anorexia
much better than we did even five years ago. One of the develop and the rabbit is brought to the hospital. The
most vexing problems in rabbit medicine has been change in the bacterial population may predispose the
disease of the teeth and jaw abscesses. It is apparent now rabbit to other bacterial infections.
that in most rabbits these conditions are related. It is Great strides have also been made in our
almost unheard of to have a jaw abscess without understanding of some of the diseases that plague pet
concomitant dental disease. In the past we admitted to ferrets. The two most common diseases in older ferrets,
not understanding the etiology of these jaw abscesses insulinoma and adrenal gland disease, still perplex
and explained them away as spontaneous infections of owners and veterinarians, but our understanding
the bone. Not knowing the etiology, we would explain it through the last decade has improved our care of these
as sepsis due to an infection in some far away part of the pets. We understand that surgery, not medical treatment,
body. We would try treating for liver abscesses or is the best overall treatment for insulinoma. We are
pneumonia or pyelonephritis that we supposed existed, better prepared to counsel owners on how to recognize
even though there was no supporting evidence. We now signs of this disease in their pet ferrets. Our knowledge
have a clearer picture of the etiology of jaw abscesses; of adrenal gland disease has greatly increased over the
elongated, overgrowing premolar and molar tooth roots last 15 years. We still may not understand the etiology,
causing damage to the maxilla and mandible and but we now have more treatment options and have a
allowing the cesspool of bacteria in the mouth to invade larger knowledge base with which to advise owners
the bone. No longer do we place the blame solely on intelligently on the prognosis and choices they have for
Pasteurella multocida for these infections. In fact, their pets with this disease. Other aspects of ferret
Pasteurella organisms play only a role in jaw abscesses. medicine have also improved over the years.
Likewise, we understand the pathophysiology of dental Gastrointestinal diseases have changed over the last
disease much better today than we did ten years ago. We decade, but we are in a better position to recommend
understand that incisor malocclusion may be secondary treatment options. Vaccines are still used in ferrets and
to cheek teeth disease. We cannot treat incisor disease we understand better how to utilize them.
successfully unless we also address the cheek tooth Guinea pigs and other small rodents are seen more
disease, the primary cause of the problem. Although we frequently in veterinary practices today than they were
do not have all of the answers, our understanding even ten years ago. Since we have a larger database of
permits us to diagnose the disease sooner, plan more knowledge, we are in a better position to advise the
effective treatments, and give a more realistic prognosis client on the treatment and prognosis of the diseases we
to the owners. see in these patients. We still run up against the problem
Another area of rabbit medicine in which great strides of balancing the cost of testing against what the owner is
have been made in developing better veterinary care is prepared to pay. However, the basics of veterinary care
proper nutrition. We have left behind the idea of a are still important. How to take blood, what to feed, and
complete diet being fed ad libitum; ‘any brand’ rabbit how to handle these pets are skills that we are still
pellets with some dried-out leafless alfalfa on the side. learning, since we are not given this type of information
Although the entire story of proper rabbit nutrition has in veterinary school. Ectoparasites continue to plague
yet to be written, the dangers inherent in the diet we these small mammals, but they are easy and inexpensive
used to feed is becoming clearer to even the most to diagnose, the signs are usually obvious, treatments are
stubborn adherent to a pelleted diet. It is more difficult easy to administer, and the pet can be cured. Of course,
to convince the owner that the convenience of a pelleted this whole process cannot start unless the veterinarian is
diet may be condemning their rabbit to a less than armed with the knowledge that ectoparasites are
healthy lifestyle, but we have the information available common problems in small mammals.
9