Skin diseases of rodents and small exotic mammals.

Small exotic mammals and rodents are becoming popular pets in the United States. Like most other exotics, the popularity of these animals has vastly preceded the accumulation of practical husbandry and veterinary information available about them. Several dermatologic conditions have been described in most rodents and small exotic mammals; however, the practitioner can assume that more exist that have not yet been diagnosed or documented. It is not unreasonable to assume that rodents and small exotic mammals could be affected by many of the same dermatologic conditions well described in other animals. Veterinarians are encouraged always to apply the same diagnostic protocols used to work up skin problems in dogs and cats when presented with an exotic pet with a dermatologic disease.     

Orthopedic radiography in exotic animal practice.

Radiographic examination of exotic animal species provides significant diagnostic information to the practitioner so long as attention is paid to positioning and radiographic detail and if variations in normal radiographic anatomy are contemplated. Fracture of pneumatic bones (humerus or femur) in avian patients often results in subcutaneous emphysema, much like an open fracture. If fracture alignment is anatomical, there is generally little callous formation visible in avian and reptile patients; however, if malunion occurs, then certainly callous can be visualized. Aggressive or excessive periosteal proliferation in exotic species often predicts osteomyelitis. Practitioners can increase their diagnostic capabilities and thereby decrease any preconceived anxiety by applying the same general interpretive concepts used in the radiography of more routine small animal patients and by evaluating the resultant radiographs in a systematic manner. With the exception of certain anatomical differences and alterations in response to injury, exotic animal species suffer the same types of orthopedic disease do dogs and cats.     

Equipping the exotic mammal practice.

Many tools used in small animal practice can be adapted for use with exotic mammals. For those veterinarians with a strong interest in exotic mammals, specific equipment and supply needs need to be taken under consideration. Initial investment need not be great to get started with special species, and as the practice develops more specialized equipment can be added. Starting with equipment that aids in patient husbandry, diagnostic sampling, and routine hospital medical and surgical care is very helpful in creating confidence and expertise with these species. As the practice case load grows more sophisticated, equipment can be added, allowing for better diagnostic workups, medical treatment, and surgical care. The right equipment for the right job makes for a more rewarding and efficient exotic mammal practice. The author describes equipment and products (Table 1) he routinely uses in his private practice, and has provided a list of available sources. Readers should keep in mind that this list is not all-inclusive, and that in many instances products discussed can be found from multiple veterinary distributors or vendors. The author does not promote or recommend one supplier or manufacturer over another.     

Diagnostic cytology of fish.

Cytology is an essential part of a diagnostic workup in cases of aquatic animal diseases. It is simple to perform, inexpensive, and can yield quick and valuable results. External parasites, bacterial and fungal diseases, and gastrointestinal infestations are easily determined with wet mount cytology. Because of the relatively small number of nonlethal diagnostic techniques available for aquatic species, cytologic testing should be considered in every case. Early diagnosis can lead to more effective treatment plans, ensuring a better prognostic outcome in our patients.     

Squash-prep cytology in the diagnosis of canine and feline nervous system lesions: a study of 42 cases

BACKGROUND: The increased sophistication of imaging techniques in veterinary medicine allows the detection of a wide variety of intracranial and intraspinal lesions; however, imaging often does not provide a definitive diagnosis for nervous system (NS) lesions. Cytology is emerging as a useful diagnostic tool for obtaining a fast and accurate assessment of NS lesions, but little information is available for dogs and cats. OBJECTIVES: The purpose of this study was to assess the accuracy of cytologic evaluation of squash samples from NS lesions in dogs and cats and to consider cytology-based diagnostic guidelines and sources of misdiagnosis. METHODS: Cytologic specimens from masses localized in the central and peripheral NS taken during surgery or postmortem examination were classified into 3 groups according to the final histopathologic diagnosis: Group 1 = completely correct diagnosis, when the cytologic diagnosis and final histologic diagnosis were exactly correlated; Group 2 = partial correlation, when the cytologic diagnosis only partially correlated with the final histologic diagnosis, and Group 3 = no correlation, when the cytologic diagnosis was incorrect and there was no correlation with the general histologic type of lesion. The diagnostic accuracy of cytopathology was calculated by considering the histopathologic diagnosis as the "gold standard," and calculating a 95% confidence interval (CI). RESULTS: A total of 42 animals (33 dogs and 9 cats) were included in the study. The cytologic diagnoses were classified in Group 1 for 32 cases (76%; 95% CI 0.63-0.89), in Group 2 for 6 cases (14%; 95% CI 0.04-0.25), and in Group 3 for 4 cases (10%; 95% CI 0.006-0.18). Considering both complete and partial correlation as an adequate result, cytologic diagnosis was satisfactory in 90% of biopsies. CONCLUSIONS: Although the current series of cases is relatively small, cytologic evaluation of squash preparations can be considered a fairly accurate and reliable tool in the diagnosis of NS lesions.     

Emergency and Critical Care Procedures in Sugar Gliders (Petaurus breviceps), African Hedgehogs (Atelerix albiventris), and Prairie Dogs (Cynomys spp).

Less common exotic pet mammals are gaining in popularity. The Australian Sugar Glider, African Hedgehog, and prairie dog are seen regularly in exotic animal practices. They are subject to the same types of medical emergencies as more traditional pets, with the unfortunate addition of all too common underlying nutritional and husbandry-related disorders. Emergency stabilization and critical care are important first steps before collection of diagnostic test samples and administration of definitive medical care.     

Renal cytology.

FNA of renal tissue is a rapid and noninvasive diagnostic tool that can be optimized by a thorough understanding of renal diseases, anatomy, and the ultrasonographic appearance of lesions likely to exfoliate for cytology. Signalment, history, and ancillary laboratory tests can narrow the list of differential diagnoses and help to determine whether cytologic evaluation will be sufficient or whether tissue architecture is needed for a definitive diagnosis. Renal cytology is particularly useful for the diagnosis of inflammation and neoplasia, including abscesses, FIP, mycotic infections, lymphoma, carcinoma, and metastatic neoplasia.     

Critical Care of the Exotic Companion Mammal (With a Focus on Herbivorous Species): The First Twenty-Four Hours

The number of pet herbivorous exotic mammals is increasing, and their owners are demanding quality medical care. Successful treatment of the critical herbivorous exotic mammal patient is complicated by small patient size, physiological diversity, and a lack of research and clinical data regarding therapeutic response to disease conditions. Despite these impediments, the same principles and techniques used in other domestic animals, such as dogs and cats, can be applied to the herbivorous exotic mammal patient.     

Evidence-based Medicine in Small Mammals

Evidence-based medicine in small exotic mammals is often considered challenging because of a lack of information related to reference data, validated diagnostic tests, treatment outcome, side effects, long-term prognosis, and financial constraints of the owner. However, despite this lack of information, it is still possible to provide good medical care to small exotic mammals and confirm a disease diagnosis that can be properly treated. With many small exotic mammal cases, the condition of the animal and, ultimately, the disease diagnosis, may not be familiar to the attending veterinarian, and in some cases the disease itself may not have ever been described in that species in the scientific literature. This article describes the process of diagnosing hyperthyroidism in a guinea pig using a recommended patient assessment, diagnostic, and treatment protocol.     

Advances in Exotic Mammal Clinical Therapeutics

It is imperative that the veterinarian treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety and efficacy. Sustained-release formulations of commonly used drugs, as well as newer routes for administration of therapeutic agents, allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded; therefore, research studies are warranted regarding potential problems associated with these formulations. However, newer studies have been published that provide the basis for exploring the use of different vehicles, frequency of dosing, and drug delivery techniques for various classes of drugs in exotic mammals. The goals of this review are to not only evaluate new medications or uses for medications in companion exotic mammal patients but also review new methods of drug delivery that might be useful to the veterinarian who treats these animals.     

Emergency Presentations Associated with Cardiovascular Disease in Exotic Herbivores

Exotic animals, including small herbivores, are increasing in popularity as companion animals. Commonly owned exotic herbivores include guinea pigs, chinchillas, and rabbits. These animals fall into the category of prey species with an inherent instinct to hide their illness until severely affected by the disease process. Therefore, any of these animals presented as an emergency case must be carefully evaluated for chronic underlying illness. Cardiovascular emergency and critical care principles are similar across all mammalian species. However, specialized techniques and adaptations are occasionally required because of the unique physiology and natural behaviors of these animals. It is essential to evaluate and stabilize these patients before attempting definitive diagnostic plans. Emergency cardiovascular presentations, as in other mammals, consist of congestive heart failure, arrhythmias, pericardial effusion, and toxicities that can result in cardiac and pulmonary arrest. Cardiac disease is a relatively common finding in small exotic mammals, but there are few peer-reviewed reports regarding diagnosis and treatment of heart disease in these species. Diagnostic testing and treatment options are generally based on knowledge of small animal medicine.     

Future directions in training of veterinarians for small exotic mammal medicine: expectations, potential, opportunities, and mandates

Small exotic mammals have been companions to people for almost as long as dogs and cats have been. The challenge for veterinary medicine today is to decipher the tea leaves and determine whether small mammals are fad or transient pets or whether they will still be popular in 20 years. This article focuses on pet small-mammal medicine, as the concerns of the laboratory animal are better known and may differ profoundly from those of a pet. Dozens of species of small exotic mammals are kept as pets. These pet small-mammal species have historically served human purposes other than companionship: for hunting, for their pelts, or for meat. Now, they are common pets. At present, most veterinary schools lack courses in the medical care of these animals. Veterinary students need at least one required class to introduce them to these pets. Currently, there are no small-mammal-only residency programs. This does not correspond with current needs. The only way to judge current needs is by assessing what employers are looking for. In a recent JAVMA classified section, almost 30% of small-animal practices in suburban/urban areas were hiring veterinarians with knowledge of exotic pets. All veterinarians must recognize that pet exotic small mammals have changed the landscape of small-animal medicine. It is a reality that, today, many small-animal practices see pet exotic small mammals on a daily basis.     

Cytologic diagnosis of diseases of invertebrates.

Invertebrate medicine in the context of an exotic or zoo animal veterinary practice is in its infancy. Establishment of species-specific reference values and evaluation of the effectiveness of cytology for diagnosis of specific diseases are necessary. Despite the lack of normal reference parameters for most species encountered in clinical practice, important information may be obtained from cytologic examination of tissue imprints, aspirates, scrapings, and hemolymph. This information may be essential to establish a specific diagnosis, focus investigations, and influence treatments. It is hoped that this article stimulates veterinarians who work with invertebrates to use diagnostic cytology and disseminate the results of their experience.     

Recently described scrapie-like encephalopathies of animals: case definitions.

Since 1986, naturally occurring scrapie-like encephalopathies have been described in the United Kingdom in domestic cattle, in five species of captive exotic bovids and in domestic cats. The disease in domestic cattle, bovine spongiform encephalopathy, has been characterised by all currently available diagnostic criteria as a transmissible spongiform encephalopathy or 'prion' disease, and has been shown to have a dietary origin. The pathology in the other species is also entirely consistent with the scrapie-like diseases. The contemporaneous occurrence in the UK of such disease in these species suggests a close epidemiological association. The diagnostic criteria of the scrapie-like encephalopathies of animals are reviewed in the light of experience with the recent extension of their natural host range.     

Equine endometrial cytology

The simplicity of collection of material for cytologic preparations belies the complexity of smear interpretation beyond recognition of neutrophils. Knowledge concerning cancer cytology moves rapidly, for cancer is a progressive, often fatal disease so that tissue for comparison and confirmation of interpretation often becomes available. This is not true for cytologic study of the equine endometrium. Lesions detected by means of cytology smears may be transient and regress, offering little information concerning their etiology or consequences. They may be focal and missed in the corresponding biopsy. Such experiences should lead to the abandonment of equine endometrial cytology, but have only strengthened our interest and enthusiasm for this technique in the study of the uterus. We have found it to be useful in a limited number of clinical circumstances in which other techniques have failed. This, plus the growing number of supportive clinicians using cytopathology service and the large number of mares with fertility problems, leads us to believe that further investigation of equine endometrial cytology may prove to be even more helpful as a clinical tool.     

Cytology of the pancreas.

Pancreatic fine-needle biopsy and cytologic evaluation is an important diagnostic tool that is not commonly used in veterinary medicine. This article discusses how to obtain and interpret pancreatic fine-needle biopsies. Normal pancreatic cytology, along with the potential diagnostic pitfalls, is also outlined. The cytologic features of pancreatic inflammation, hyperplasia, and neoplasia are discussed and illustrated.     

Nonreproductive surgery in small mammals.

The sophistication of soft-tissue surgery techniques in small mammals is increasing rapidly. Exotic animal practitioners must be familiar with the diseases, conditions, and anatomic variations of each small-mammal species. The small size of these patients should not preclude the use of technologic advances available for other small animals. Despite these challenges, successful resolution of surgical problems in small exotic mammals is not only possible but also should be the expected result of veterinarians' efforts in such cases.     

Conjunctival swab cytology from a guinea pig: it's elementary!

Three 3-month-old guinea pigs (Cavia porcellus) were evaluated for purulent ocular discharge. Conjunctival swabs were obtained for cytologic evaluation of Wright's-Giemsa-stained preparations. The specimen from the most severely affected guinea pig consisted primarily of karyolytic neutrophils and small lymphocytes. Epithelial cells occasionally were observed that contained intracytoplasmic coccoid basophilic organisms, 0.5-1.5 microm in diameter. The intraepithelial inclusions were most consistent with Chlamydia sp elementary and reticulate bodies. Specimens from the other 2 guinea pigs had a similar inflammatory response, but organisms were not observed. Polymerase chain reaction (PCR) analysis of a conjunctival swab from the most severely affected guinea pig was positive for C psittaci, which also is referred to as Chlamydophila caviae, immunotype 8, formerly known as the guinea pig inclusion conjunctivitis strain of C psittaci. Chlamydial conjunctivitis is a common problem in guinea pig populations, with C caviae being specific for this species. Cytologic identification of elementary or reticulate bodies within epithelial cells is diagnostic for the organism in Giemsa-stained preparations. However, PCR is an important complementary tool when organisms are not observed and for accurate classification of the Chlamydia species.     

Safe Sedation and Immobilization of Unusual Exotic Species Encountered in Practice

Safe handling techniques for traditional exotic companion mammals (e.g., ferrets, rabbits, and rodents) have been well described. However, some uncommon species, including various wild animals maintained as pets, should not be manually restrained because of the nature of the animal and the potential for injury to both the pet and the handler. Sedation and immobilization techniques are useful to enhance safety and to facilitate diagnostic and treatment procedures. Sedatives are best administered to these animals with the aid of a squeeze cage.     

Evaluation of sensitivity and specificity of cytologic examination: 269 cases (1999-2000)

OBJECTIVE: To determine sensitivity and specificity of cytologic examination used in a clinical setting. DESIGN: Retrospective study. ANIMALS: 216 dogs, 44 cats, 4 horses, 2 ferrets, 1 llama, 1 rat, and 1 mouse. PROCEDURE: Records were reviewed of cases in which a cytologic diagnosis was followed by a surgical biopsy or postmortem examination within 3 days with subsequent histopathologic diagnosis. Diagnoses were compared for agreement at various levels, including complete agreement, partial agreement, no agreement, or no comparison possible because of insufficient or incorrect cytologic specimen. Levels of agreement were compared for different categories of lesions, including neoplastic, inflammatory, dysplastic-hyperplastic-other, and normal tissue. Additionally, levels of agreement for neoplastic lesions were categorized with regard to cell type, degree of malignancy, and location. Sensitivity and specificity of cytologic examination were calculated. RESULTS: At the level of general agreement (complete and partial agreement), the sensitivity of cytologic examination ranged from 33.3 to 66.1%, depending on the location of the lesion. Cytologic examination was most accurate when used to diagnose cutaneous and subcutaneous lesions and least accurate for diagnosis of liver lesions. Cytologic examination was most effective in diagnosis of neoplastic disease and least effective in diagnosis of dysplastic or hyperplastic conditions. CONCLUSIONS AND CLINICAL RELEVANCE: Cytologic examination is a valuable diagnostic tool, although our results indicated lower accuracy than previously reported. False-negative results (missing a diagnosis) were far more common than false-positive results (categorizing a healthy animal as diseased): therefore, if the clinical index of suspicion is high, cytologic examination should be repeated or another technique should be selected to rule out the suspected condition.