Evaluation of an inactivated rabies virus vaccine in domestic ferrets

Efficacy of an SC-administered commercial inactivated vaccine for prevention of rabies was evaluated in domestic ferrets. Ferret immunity was challenged by the IM inoculation of street rabies virus. All ferrets developed titers of rabies virus-neutralizing antibodies within 30 days of vaccination (geometric mean titer [GMT] = 154, n = 41) that were maintained for at least one year (GMT = 106, n = 36), compared with no seroconversion in controls (GMT less than 5, n = 39). Following rabies virus challenge inoculation, 89% (32/36) of vaccinated ferrets survived vs less than 6% (2/38) survival in control ferrets. These results demonstrate the protective efficacy of a commercial, inactivated rabies vaccine of at least one year's duration for domestic ferrets.     

Adrenal teratoma in four domestic ferrets (Mustela putorius furo)

Teratomas are histologically complex neoplasms that are composed of structures derived from multiple germ cell layers (ectoderm, mesoderm, and endoderm). These neoplasms are uncommon in domestic animals and are usually found in the gonads. This paper describes teratomas of the adrenal gland in four domestic ferrets (Mustela putorius furo). Three of four of the neoplasms contained tissues from ectodermal, mesodermal, and endodermal germ cell layers; two of four contained rudimentary teeth. In one case, malignant epithelial cells had metastasized to local lymph nodes. Teratomas, although uncommon, should be included in the differential diagnosis for adrenal neoplasms in domestic ferrets.     

Laboratory findings, histopathology, and immunophenotype of lymphoma in domestic ferrets

Lymphoma is a common tumor in ferrets, but anatomic distribution, histomorphology, immunophenotype, laboratory abnormalities, and response to chemotherapy are incompletely defined. In this study, lymphoma was diagnosed by histopathology of tumor tissue in 29 ferrets ranging in age from 0.8 to 8.5 years, including 12 males and 17 females. Tumors involved the viscera of the abdominal cavity (n = 11), thoracic cavity (n = 1), or abdominal and thoracic cavities (n = 7); the skin (n = 2); or the viscera of both body cavities plus other sites (n = 8). Microscopically, all tumors had diffuse architecture. Assessment by histomorphology and immunophenotype classified tumors as peripheral T-cell lymphoma (n = 17), anaplastic large T-cell lymphoma (n = 5), anaplastic large B-cell lymphoma (n = 4), diffuse large B-cell lymphoma (n = 1), and Hodgkin-like lymphoma (n = 2). Cytologic evaluation of tumor tissue was diagnostic in 11 of 13 cases. Twenty-two of 27 ferrets had anemia, 2 had leukemia, and 5 were neutropenic. Common comorbid disorders were adrenal disease (n = 27) and insulinoma (n = 6). Tumors most frequently involved mesenteric lymph nodes, while enlargement of peripheral lymph nodes was uncommon (n = 3). Ferrets with Hodgkin-like lymphoma had massive enlargement of single lymph nodes. Mean survival of ferrets not immediately euthanized was 5.0 months (T-cell lymphoma) and 8.4 months (B-cell lymphoma). Ferrets treated with chemotherapy survived an average of 4.3 months (T-cell lymphoma, n = 9) or 8.8 months (B-cell lymphoma, n = 4). Results indicate that lymphomas in ferrets most commonly affect abdominal viscera, may be amenable to cytologic diagnosis, are frequently associated with anemia and, in some cases, may be chemosensitive, resulting in relatively long survival times.     

Lack of detectable blood groups in domestic ferrets: implications for transfusion

Evidence of blood groups in domestic ferrets was sought by testing serum samples for naturally acquired or experimentally induced erythrocyte antibodies. All sera were tested for ability to cause direct agglutination, antiglobulin-enhanced (Coombs test) agglutination, or lysis. Examination of 212 randomly paired combinations of ferret serum and erythrocytes produced no evidence of naturally acquired blood group antibodies. Six pairs of ferrets were reciprocally transfused twice, 34 days apart, with 6-ml quantities of anticoagulated blood. All were tested 21 days after the first transfusion, as well as 10 and 30 days after the second transfusion; erythrocyte antibodies were not detected. Four additional pairs of ferrets were reciprocally inoculated SC with a series of six 1.25-ml quantities of blood in Alsever solution, administered over a 3-week period, and tested 8 days after the last injection; again, erythrocyte antibodies could not be detected. These observations suggest that blood groups of the kind in human beings and other mammals either do not exist in domestic ferrets or represent antigen systems too weak to elicit measurable responses under the reported conditions. It appears, therefore, that transfusion in this species poses little clinical risk, even without crossmatching.     

Outbreak of canine distemper in domestic ferrets (Mustela putorius furo)

In 2006 an outbreak of canine distemper affected 14 young domestic ferrets in Barcelona, Spain. Their clinical signs included a reduced appetite, lethargy, dyspnoea, coughing, sneezing, mucopurulent ocular and nasal discharges, facial and perineal dermatitis, diarrhoea, splenomegaly and fever. Late in the course of the disease, general desquamation and pruritus, and hyperkeratotic/crusting dermatitis of the lips, eyes, nose, footpads, and perineal area were observed. None of the ferrets developed neurological signs. Non-regenerative anaemia and high serum concentrations of alpha- and beta-globulins were the most common laboratory findings. Most of the animals died or were euthanased because of respiratory complications. Postmortem there were no signs of lung collapse. Distemper was diagnosed by direct immunofluorescence of conjunctival swabs or pcr of several organs, and histology revealed the characteristic eosinophilic intracytoplasmic and intranuclear inclusion bodies of canine distemper virus in several organs. The minimum incubation periods calculated for six of the ferrets were 11 to 56 days, and in 13 of the ferrets the signs of disease lasted 14 to 34 days. Inclusion bodies compatible with infection by herpesvirus were found in the lungs of one of the ferrets.     

Comparison of sevoflurane and isoflurane in domestic ferrets (Mustela putorius furo)

Isoflurane anesthesia is commonly used in ferrets for routine examinations and diagnostics. Sevoflurane is now being used as well, but there have been no studies to date directly comparing these agents in domestic ferrets. A prospective study was designed to evaluate the quality and speed of anesthetic induction and recovery using isoflurane and sevoflurane in ferrets. In addition effects on heart rate, blood pressure and packed cell volume were also recorded. No significant differences were noted between anesthetic agents.     

Effects of melatonin administration on the clinical course of adrenocortical disease in domestic ferrets

OBJECTIVE: To evaluate the effect of oral administration of melatonin on clinical signs, tumor size, and serum steroid hormone concentrations in ferrets with adrenocortical disease. DESIGN: Noncontrolled clinical trial. ANIMALS: 10 adult ferrets with clinical signs of adrenocortical disease (confirmed via serum steroid hormone concentration assessments). PROCEDURES: Melatonin (0.5 mg) was administered orally to ferrets once daily for 1 year. At 4-month intervals, a complete physical examination; abdominal ultrasonographic examination (including adrenal gland measurement); CBC; serum biochemical analyses; and assessment of serum estradiol, androstenedione, and 17alpha-hydroxyprogesterone concentrations were performed. Serum prolactin and dehydroepiandrosterone sulfate concentrations were evaluated at the first, second, and last examinations, and serum cortisol concentration was evaluated at the first and last examinations. RESULTS: Daily oral administration of melatonin greatly affected clinical signs of adrenocortical disease in ferrets; changes included hair regrowth, decreased pruritus, increased activity level and appetite, and decreased vulva or prostate size. Mean width of the abnormally large adrenal glands was significantly increased after the 12-month treatment period. Recurrence of clinical signs was detected in 6 ferrets at the 8-month evaluation. Compared with pretreatment values, serum 17alpha-hydroxyprogesterone and prolactin concentrations were significantly increased and decreased after 12 months, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that melatonin is a useful, easily administered, palliative treatment to decrease clinical signs associated with adrenocortical disease in ferrets, and positive effects of daily treatment were evident for at least an 8-month period. Oral administration of melatonin did not decrease adrenal gland tumor growth in treated ferrets.     

Ultrasonographic visualization of the adrenal glands of healthy ferrets and ferrets with hyperadrenocorticism

A protocol was developed to compare the ultrasonographic characteristics of the adrenal glands of 21 healthy ferrets and 37 ferrets with hyperadrenocorticism. By using specific landmarks, the adrenal glands were imaged in 97% of the cases. The adrenal glands of ferrets with hyperadrenocorticism had a significantly increased thickness, with changes in shape, structure, and echogenicity compared to the adrenal glands of healthy ferrets. Based on the findings of the study, adrenal glands may be classified as abnormal when they have a rounded appearance, increased size of the cranial/caudal pole (thickness >3.9 mm), a heterogeneous structure, increased echogenicity, and/or signs of mineralization.     

Pneumonia due to Mycobacterium abscessus in two domestic ferrets (Mustelo putorius furo)

Two ferrets were diagnosed with pneumonia due to Mycobacterium abscessus. Both cases were treated successfully using clarithromycin after positive cultures were obtained via unguided bronchoalveolar lavage. This is the first time M abscessus has been isolated in our laboratory and the first report of this organism causing disease in companion animals in Australia. Underlying respiratory tract disease was thought to be an important factor in the development of the infections. Thorough investigation of chronic lower respiratory tract disease in ferrets is recommended as this species appears predisposed to atypical infections.     

Granulocytopenia associated with thymoma in a domestic shorthaired cat

A 5-year-old, spayed female cat was referred because of a mass in the cranial mediastinum noted on thoracic radiographs. A thymoma was diagnosed following ultrasound and biopsy of the mass. Treatment was initiated with coarse-fraction radiation therapy using external-beam therapy (four fractions of 5 Gy). The mass responded, but granulocytopenia developed. Bone marrow examination showed a myeloid to erythroid ratio of approximately 1:1, with a left shift within the myeloid line. These findings, as well as the lack of toxic changes within the peripheral blood neutrophils, suggested immune-mediated destruction of peripheral granulocytes. Immune suppression with prednisone and cyclosporine was instituted. After 7 weeks, the neutrophil count returned to normal. The tumor was removed, and cyclosporine was reduced and eventually discontinued 3 weeks postsurgery.     

Clinicopathologic abnormalities associated with snake envenomation in domestic animals

Envenomation of domestic animals by snakes occurs frequently in certain geographic areas. However, reports describing clinical signs, clinicopathologic abnormalities, therapeutic approaches, and outcomes are sparse. This review summarizes various snake families, venom types associated with harmful snakes, and the significant hematologic, hemostatic, and biochemical abnormalities associated with envenomation. Hematologic abnormalities include RBC membrane abnormalities, hemolysis, hemoconcentration, leukogram changes, and platelet abnormalities, specifically thrombocytopenia. Coagulopathies associated with snake envenomation are well described in human medicine, and many studies have demonstrated properties of venoms that lead to both procoagulation and anticoagulation. As expected, similar abnormalities have been described in domestic animals. Biochemical abnormalities are associated with the effects of venom on tissues such as liver, skeletal and cardiac muscle, vascular endothelium, and kidney as well as effects on protein components and cholesterol. This comprehensive review of clinicopathologic abnormalities associated with envenomation and their relationships to characterized venom constituents should be useful both in the diagnosis and management of envenomation and should serve as a foundation for future research in this field.     

High mortality of domestic turkeys associated with Ascaridia dissimilis.

Third- and fourth-stage Ascaridia dissimilis larvae were isolated from commercial white turkey intestinal scrapings from two farms that were experiencing high mortality. Lesions consisted of a necrotic-like enteritis that was most severe in the jejunum. Subsequent bacteriological isolation yielded heavy growth of Escherichia coli and Clostridium perfringens. The rate of mortality declined rapidly when the turkeys were administered 18 ppm fenbendazole for 7 days.     

Incidence of and risk factors for adverse events associated with distemper and rabies vaccine administration in ferrets

OBJECTIVE: To determine incidence of and risk factors for adverse events associated with distemper and rabies vaccine administration in ferrets. DESIGN: Retrospective cohort study. ANIMALS: 3,587 ferrets that received a rabies or distemper vaccine between January 1, 2002, and December 31, 2003. PROCEDURES: Electronic medical records were searched for possible vaccine-associated adverse events. Adverse events were classified by attending veterinarians as nonspecific vaccine reactions, allergic reactions, or anaphylaxis. Patient information that was collected included age, weight, sex, cumulative number of distemper and rabies vaccinations received, clinical signs, and treatment. The association between potential risk factors and occurrence of an adverse event was estimated with logistic regression. RESULTS: 30 adverse events were recorded. The adverse event incidence rates for administration of rabies vaccine alone, distemper vaccine alone, and rabies and distemper vaccines together were 0.51%, 1.00%, and 0.85%, respectively. These rates were not significantly different. All adverse events occurred immediately following vaccine administration and most commonly consisted of vomiting and diarrhea (52%) or vomiting alone (31%). Age, sex, and body weight were not significantly associated with occurrence of adverse events, but adverse event incidence rate increased as the cumulative number of distemper or rabies vaccinations received increased. In multivariate logistic regression analysis, only the cumulative number of distemper vaccinations received was significantly associated with the occurrence of an adverse event. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in ferrets, the risk of vaccine-associated adverse events was primarily associated with an increase in the number of distemper vaccinations.     

Histologic features associated with tritrichomonas foetus-induced colitis in domestic cats

Tritrichomonas foetus is a venereal pathogen of naturally bred cattle. In domestic cats, T. foetus colonizes the colon, resulting in chronic, large-bowel diarrhea. The infection is prevalent among young, densely housed cats, and there is no effective treatment. To the authors' knowledge, the characteristic microscopic lesions of T. foetus infection in naturally infected cats have not been described. The aim of the study reported here was to characterize the histologic changes in the colon of seven cats with T. foetus infection and chronic diarrhea. All cats were 1 year old or younger (mean, 6.7 +/- 1.7 months), and a diagnosis of T. foetus infection was made on the basis of direct fecal smear examination (five cats), fecal culture in InPouch TF medium (four cats), single-tube nested polymerase chain reaction (PCR) analysis of DNA extracted from feces (two cats), or observation of trichomonads in sections of colon followed by PCR confirmation on DNA extracted from paraffin-embedded tissue (two cats). The presence of colonic trichomonads was the most diagnostic histologic feature. Organisms were identified in all cats, but in only 24 of 43 (56%) sections of colon. Trichomonads were generally present in close proximity to the mucosal surface and less frequently in the lumen of colonic crypts. The presence of colonic trichomonads was consistently associated with mild-to-moderate lymphoplasmacytic and neutrophilic colitis, crypt epithelial cell hypertrophy, hyperplasia and increased mitotic activity, loss of goblet cells, crypt microabscesses, and attenuation of the superficial colonic mucosa. In two of the cats, histologic lesions were more severe and were associated with invasion of trichomonads into the lamina propria and/or deeper layers of the colon.