Natural West Nile virus infection in a captive juvenile Arctic wolf (Canis lupus).

A case of West Nile virus (WNV) infection in a captive 4-month-old Arctic wolf (Canis lupus) is described. The animal had vomiting, anorexia, and ataxia before death. Histopathology revealed multifocal severe renal lymphoplasmacytic vasculitis, mostly affecting small arterioles, with fibrinoid degeneration of some vessel walls. Many small foci of gliosis were detected in the cerebral cortex. West Nile virus was demonstrated in the kidneys and cerebrum by immunohistochemistry and polymerase chain reaction. The described renal changes represent a novel pathological finding of WNV infection.     

Tp53 expressing squamous cell carcinoma of the tonsil in a captive polar wolf (Canis lupus arctos).

The gross and histopathologic findings for a primary tonsillar squamous cell carcinoma in a captive 11-yr-old male polar wolf (Canis lupus arctos) are described. The carcinoma had metastasized to regional lymph nodes of the pharynx, the precardial mediastinum, and the lungs. Tumor suppressor protein TP53 was detected by immunohistochemistry in the nuclei of poorly differentiated, cytokeratin-positive cells of the primary neoplasm and the metastases. Canine oral papillomavirus DNA was not detectable by polymerase chain reaction (PCR).     

Gray wolf (Canis lupus) is a natural definitive host for Neospora caninum

The gray wolf (Canis lupus) was found to be a new natural definitive host for Neospora caninum. Neospora-like oocysts were found microscopically in the feces of three of 73 wolves from Minnesota examined at necropsy. N. caninum-specific DNA was amplified from the oocysts of all three wolves. Oocysts from one wolf were infective for the gamma interferon gene knock out (KO) mice. Viable N. caninum (designated NcWolfUS1) was isolated in cell cultures seeded with tissue homogenate from the infected mouse. Typical thick walled tissue cysts were found in outbred mice inoculated with the parasite from the KO mouse. Tissue stages in mice stained positively with N. caninum-specific polyclonal antibodies. Our observation suggests that wolves may be an important link in the sylvatic cycle of N. caninum.     

Serum biochemistry of captive and free-ranging gray wolves (Canis lupus).

Normal serum biochemistry values are frequently obtained from studies of captive sedentary (zoo) or free-ranging (wild) animals. It is frequently assumed that values obtained from these two populations are directly referable to each other. We tested this assumption using 20 captive gray wolves (Canis lupus) in Minnesota, USA, and 11 free-ranging gray wolves in Alaska, USA. Free-ranging wolves had significantly (P < 0.05) lower sodium, chloride, and creatinine concentrations and significantly higher potassium and blood urea nitrogen (BUN) concentrations; BUN to creatinine ratios; and alanine aminotransferase, aspartate aminotransferase, and creatine kinase activities relative to captive wolves. Corticosteroid-induced alkaline phosphatase activity (a marker of stress in domestic dogs) was detected in 3 of 11 free-ranging wolves and in 0 of 20 captive wolves (P = 0.037). This study provides clear evidence that serum biochemical differences can exist between captive and free-ranging populations of one species. Accordingly, evaluation of the health status of an animal should incorporate an understanding of the potential confounding effect that nutrition, activity level, and environmental stress could have on the factor(s) being measured.     

Antibody response to rabies vaccination in captive and free-ranging wolves (Canis lupus).

Fourteen captive and five free-ranging Minnesota gray wolves (Canis lupus) were tested for the presence of rabies virus neutralizing antibodies (RVNA) after vaccination with an inactivated canine rabies vaccine. Blood was collected from all wolves prior to vaccination and at 1 mo postvaccination (PV) and from all captive and three wild wolves at 3 mo PV. In addition, one free-ranging wolf was sampled at 4 mo PV, and two free-ranging wolves were sampled at 6 mo PV. All wolves were seronegative prior to vaccination. RVNA were detected in 14 (100%) captive wolves and in four of five (80%) free-ranging wolves. The geometric mean titer of the captive wolves at 1 mo PV was significantly higher (P = 0.023) than in the free-ranging wolves. Five of 13 (38.5%) captive wolves and none of the three (0%) free-ranging wolves had measurable RVNA at 3 mo PV. No measurable RVNA were detected in the serum samples collected from the free-ranging wolves at 4 and 6 mo PV. These results should be interpreted with caution because of the small number of free-ranging wolves tested. Further research is needed to properly assess immune function and antibody response to vaccination in captive wolves in comparison with their free-ranging counterparts.     

Subcutaneous atypical mycobacteriosis in captive tiger quolls (Dasyurus maculatus)

From July 1989 to October 1998, 9/37 (24%) adult captive tiger quolls (Dasyurus maculatus) were diagnosed with atypical mycobacterial infection involving the subcutis and skin. Females were more often affected than males (seven females, two males). Grossly, lesions presented as focal thickenings, plaques, and abscesses within the subcutis, often with fistulous tracts. The subcutis and skin overlying cervical and thoracic regions were the primary sites of infection. Cytology of subcutaneous impression smears from all nine affected tiger quolls revealed pyogranulomatous inflammation admixed with several acid-fast bacilli. Histologically, all tiger quolls had nodular to diffuse pyogranulomatous panniculitis and cellulitis. Small numbers of acid-fast bacilli were noted histologically in 7/9 (78%) animals. Skin cultures from seven tiger quolls were positive for one or more different Runyon group IV mycobacteria. The disease described in these tiger quolls is similar to subcutaneous atypical mycobacteriosis of humans and domestic animals.     

Clinical feasibility of cognitive testing in dogs (Canis lupus familiaris)

Several cognitive tests have been developed to evaluate specific aspects of human and animal learning and memory. These tests have been used for early detection of cognitive deficits and to monitor the treatment of dogs with cognitive impairment. Thus, this article evaluated the feasibility of cognitive tests for use in canine neurology clinical routines and the suitability of the different tests to accomplish this aim. Fifteen healthy adult dogs were used for the cognitive tests of reward approach learning, object approach learning, object discrimination learning, reversal learning, delayed non-matched to position, and delayed non-matched to sample to assess different aspects of memory. No difference was observed between tests of delayed non-matched to position (3.13 ± 2.23 days) and delayed non-matched to sample (3.20 ± 2.40 days) (P = 0.944). However, dogs had greater difficulty in reversal learning (8.47 ± 2.61 days) than in object discrimination learning (4.60 ± 1.64 days) (P ≤ 0.001). Based on the tests performed, the delayed non-matched to position test may be performed in clinical routine if the owner and the veterinarian have time available, because this test is sensitive to evaluate dogs with cognitive impairments, but requires approximately 10 days of training. Thus, elderly dogs are excellent experimental models to study pathological aging based on their similarities with some human brain diseases, such as Alzheimer disease.     

Cecal inversion and subsequent colocolic intussusception in a red wolf (Canis rufus gregoryi).

A 2-yr-old female red wolf (Canis rufus gregoryi) presented with weight loss and diarrhea. Abnormal clinical pathology included low serum calcium, sodium, chloride, globulin, and albumin levels. Differential diagnosis included infectious enteritis, intestinal parasitism, inflammatory bowel disease, hepatic or renal disease, and malnutrition. The wolf was treated empirically, but did not improve. A second examination revealed persistent poor musculature and stool quality. Abdominal palpation revealed a firm mass; contrast radiography confirmed an intussusception. Exploratory laparotomy revealed a colocolic intussusception involving the cecum. Following reduction of the colocolic intussusception, cecal inversion (cecocolic intussusception) was identified. Because the cecal inversion could not be reduced, typhlectomy was performed through a colotomy incision. Bacterial culture of peritoneal fluid yielded two strains of Escherichia coli. Postoperatively, the wolf was placed on antibiotics and a soft diet. The diet was gradually returned to its normal formulation and the wolf progressively gained weight. Physical examination 7.5 mo following initial presentation revealed normal body weight and condition. To our knowledge, this is the first recorded incidence of cecal inversion with concurrent colocolic intussusception.     

Echocardiographic and Doppler echocardiographic findings in 11 wolves (Canis lupus)

Two-dimensional real-time, M-mode and Doppler echocardiographic measurements were made in 11 adult wolves (Canis lupus) anaesthetised with an intramuscular combination of medetomidine, ketamine, butorphanol and acepromazine followed by isoflurane in oxygen. M-mode measurements of the left ventricle, B-mode measurements of the left atrium and aorta, systolic indices, and Doppler measurements of aortic and pulmonary blood outflow, and of mitral and tricuspid blood inflow, were recorded. The values obtained were compared with those reported for dogs of similar bodyweight and body type. The diastolic measurements of the cardiac chambers and walls were similar to those reported for healthy, conscious dogs, but the use of anaesthesia probably resulted in the markedly different systolic cardiac measurements, systolic indices and Doppler blood flow velocities observed in the wolves. Mild mitral regurgitation, probably due to mitral endocardiosis, was observed in one wolf, and trivial functional mitral insufficiency was observed in five others.     

Sustained release cyclosporine therapy for bilateral keratoconjunctivitis sicca in a red wolf (Canis rufus).

A 12-yr-old intact male red wolf (Canis rufus) diagnosed with bilateral idiopathic dry eye was treated with subconjunctival drug delivery implants designed to release therapeutic levels of cyclosporine from 12-24 mo. Normal tear production and corneal health has been maintained, alleviating the need for daily handling of the animal for topical medication.     

Prevention of coccidiosis in domestic dogs and captive coyotes (Canis latrans) with sulfadimethoxine-ormetoprim combination

Sulfadimethoxine-ormetoprim combination was evaluated as a coccidiostat against experimentally induced coccidiosis in young dogs and coyotes (Canis latrans). The animals were experimentally inoculated with 50,000 or 100,000 sporulated oocysts of Isospora ohiohensis (98%) and Isospora canis (2%). In experiment 1, daily treatment for 13 to 23 days with a combination of 27.5 mg of sulfadimethoxine/kg of body weight (BW) and 5.5 mg of ormetoprim/kg of BW admixed to the feed resulted in no significant (P greater than 0.05) difference in fecal oocyst counts between treated and nontreated groups of dogs or coyotes. In experiment 2, treatment with a combination of 55 mg of sulfadimethoxine/kg of BW and 11 mg of ormetoprim/kg of BW for 23 days was 99.8% effective against Isospora spp infections in dogs. Significantly (P less than 0.05) fewer oocysts were present in feces of treated dogs than were present in feces of nontreated dogs from first passage of oocysts at day 4 to the end of the patent period at days 19 to 21. After the 2nd week of treatment, BW of treated dogs were significantly greater (P less than 0.05) than BW of nontreated dogs. Evidence of drug toxicity was not observed clinically or by serum chemical analyses.     

MRI examination of the masticatory muscles in the gray wolf (Canis lupus), with special reference to the M. temporalis.

We examined the head of the gray wolf (Canis lupus) using MRI methods. Although the arising surface of the M. temporalis was not so enlarged in the frontal bone, the small frontal bone did not disturb the M. temporalis from occupying the lateral space of the frontal area in the gray wolf as in the domesticated dog. In the gray wolf, it is suggested that the M. temporalis may not be well-developed in terms of size of arising area, but in the thickness of running bundles. We suggest that the dog has changed the three-dimensional plan of the M. temporalis during the domestication and that the M. temporalis has developed a large arising surface in the frontal bone and lost the thickness of belly in the frontal area in accordance with the enlargement of the frontal bone and the increase in brain size.     

Spontaneous subcutaneous myxosarcoma in a captive European hedgehog (Erinsceus europaeus).

A surgically excised biopsy representing a subcutaneous mass on the left side of the neck from a 3-year-old female European hedgehog (Erinsceus europaeus) was presented. Spontaneous myxosarcoma was diagnosed based on histological, immunohistochemical, and ultrastructural characteristics. The neoplasm grossly consisted of a firm, pale, multilobulated mass with a characteristic clear gelatinous fluid. Histologically, the neoplasm was nonencapsulated and composed of pleomorphic stellate or spindle-shaped vimentin and periodic acid-Schiff-positive cells arranged in loose sheets and occasionally whorls. The neoplastic cells were suspended in Alcian blue-positive stroma and contained infrequent mitotic figures. Evidence of a viral etiology was not detected using electron microscopy and polymerase chain reaction. This is the first case report of a myxosarcoma in a captive European hedgehog.     

Oral leiomyosarcoma in a woodchuck (Marmota monax)

We report the case of a 4-year-old female woodchuck (Marmota monax) which presented with a white, firm and discrete mass in the hard palate. The mass extended into the oral cavity but it was well separated from the surrounding tissues. Histology of the tumor showed a malignant mesenchymal tumor with pleomorphic spindle cells varying in degrees of differentiation and density. The neoplastic cells had moderate amounts of granular or fibrillar eosinophilic cytoplasm with indistinct cell margins. Nuclei were oval to elongated and frequently blunt-ended with vesicular chromatin. Immunohistochemical study showed that the neoplastic cells expressed vimentin and alpha-smooth muscle actin but did not express desmin, pan-cytokeratin, and S-100. Therefore, histology and immunohistochemistry revealed that the tumor was oral leiomyosarcoma. Oral cavity is an extremely rare site for leiomyosarcoma and the present case is the first report of spontaneous oral leiomyosarcoma in animals.