Pathology of brucellosis in bison from Yellowstone National Park.

Between February 1995 and June 1999, specimens from seven aborted bison (Bison bison) fetuses or stillborn calves and their placentas, two additional placentas, three dead neonates, one 2-wk-old calf, and 35 juvenile and adult female bison from Yellowstone National Park (USA) were submitted for bacteriologic and histopathologic examination. One adult animal with a retained placenta had recently aborted. Serum samples from the 35 juvenile and adult bison were tested for Brucella spp. antibodies. Twenty-six bison, including the cow with the retained placenta, were seropositive, one was suspect, and eight were seronegative. Brucella abortus biovar 1 was isolated from three aborted fetuses and associated placentas, an additional placenta, the 2-wk-old calf, and 11 of the seropositive female bison including the animal that had recently aborted. Brucella abortus biovar 2 was isolated from one additional seropositive adult female bison. Brucella abortus was recovered from numerous tissue sites from the aborted fetuses, placentas and 2-wk-old calf. In the juvenile and adult bison, the organism was more frequently isolated from supramammary (83%), retropharyngeal (67%), and iliac (58%) lymph nodes than from other tissues cultured. Cultures from the seronegative and suspect bison were negative for B. abortus. Lesions in the B. abortus-infected, aborted placentas and fetuses consisted of necropurulent placentitis and mild bronchointerstitial pneumonia. The infected 2-wk-old calf had bronchointerstitial pneumonia, focal splenic infarction, and purulent nephritis. The recently-aborting bison cow had purulent endometritis and necropurulent placentitis. Immunohistochemical staining of tissues from the culture-positive aborted fetuses, placentas, 2-wk-old calf, and recently-aborting cow disclosed large numbers of B. abortus in placental trophoblasts and exudate, and fetal and calf lung. A similar study with the same tissue collection and culture protocol was done using six seropositive cattle from a B. abortus-infected herd in July and August, 1997. Results of the bison and cattle studies were similar.

Organochlorine contaminant levels in Eskimo harvested bowhead whales of arctic Alaska.

Organochlorine (OC) levels in liver and blubber of 20 bowhead whales (Balaena mysticetus) collected during the Eskimo subsistence harvest at Barrow (Alaska, USA) in 1992 and 1993 are presented. Liver sum DDT (lipid weight) was significantly greater in male whales than in females. Most of the organochlorines measured were at higher levels in longer (older) than in shorter (younger) males. For female bowhead whales, hexachlorobenzene and lipid levels decreased and other OC levels did not change significantly with increasing length. Most organochlorine contaminants have low concentrations in tissues of the bowhead whale compared to concentrations in tissues of other cetaceans, especially Odontocetes. Based on allowable daily intakes (ADI) levels established by the Canadian Northern Contaminants Program (Ottawa, Ontario, Canada) "safe" levels of blubber to consume were calculated. Chlordane levels in bowhead whale blubber results in the most restrictive consumption amount (50 g blubber/day). We expect no adverse effects related to these organochlorine contaminants to occur in bowhead whales or in consumers of their tissues. However, investigation of low level chronic exposure effects and a more rigorous assessment of histopathology, biomarkers, and immune status in the bowhead whale would be required to conclude "no effect" with more certainty.

Abortion and placentitis in pregnant bison (Bison bison) induced by the vaccine candidate, Brucella abortus strain RB51.

OBJECTIVE: To determine the ability of Brucella abortus strain RB51 to induce placentitis and abortion in bison after SC vaccination. ANIMALS: 10 pregnant bison cows, 3 to 10 years old and at 3 to 8 months' gestation. PROCEDURE: Pregnant bison cows on a Montana ranch were vaccinated SC with 10(9) colony-forming units of B abortus strain RB51. Two cows, identified prior to the study, were euthanatized and examined 5 weeks after vaccination to obtain optimal histologic samples of placenta. Other cows were euthanatized and examined after abortion. After euthanasia, tissue specimens were collected for histologic and immunohistochemical evaluation. Tissue and fluid specimens for bacteriologic culture were also collected during necropsy. RESULTS: Of 8 cows, 2 aborted at 68 and 107 days after vaccination. Aborting cows had endometritis. Strain RB51 was isolated from reproductive tissues and supramammary lymph nodes. Fetal lesions were not seen; however, fetal bronchial lymph nodes and amniotic fluid contained strain RB51. Cows examined 5 weeks after vaccination had placentitis and endometritis, with numerous bacteria within trophoblastic epithelial cells that were immunoreactive for strain RB51 antigen. Strain RB51 was isolated from placentomes and numerous lymph nodes. Fetal lesions were not seen 5 weeks after vaccination; however, strain RB51 was isolated from numerous lymph nodes and lung, allantoic fluid, and rectal swab specimens. CONCLUSIONS: The vaccine candidate B abortus RB51 has tropism for the bison placenta, and can cause placentitis, which induces abortion in pregnant bison. The vaccine dose used was similar to that being tested in cattle, but may not be appropriate for pregnant bison.

Serum chemistry of bowhead whales (Balaena mysticetus).

Sera of 19 male and female bowhead whales (Balaena mysticetus) collected near Barrow, Alaska (USA) between 30 August and 13 October 1992 were evaluated for 18 serum chemistry values. Male bowhead whales had significantly greater creatinine and sodium concentrations, and significantly lower glucose concentrations than females. Pregnant females had greater triglyceride levels than non-pregnant females. The mean concentrations of creatinine, blood urea nitrogen, alkaline phosphatase, total bilirubin, total protein, sodium, potassium, chloride, phosphorus, and calcium were similar to those previously reported from bowhead whales. High aspartate aminotransferase and creatinine kinase levels were attributed to muscle damage associated with harpooning.

Fractured mandible and associated oral lesions in a subsistence-harvested bowhead whale (Balaena mysticetus).

A fractured right mandible with midlength nonunion and oral lesions were noted in a subsistence-harvested female bowhead whale (Balaena mysticetus) near Wainwright, Alaska (USA). The cause of the fracture was not apparent. The fracture resulted in misalignment of the mandible. The abnormal mobility at the fracture site probably caused irregular baleen stowage within the oral cavity, leading to breakage of many baleen plates and extensive ulceration of the tongue and lips. Good body condition suggested the fracture was not debilitating.

Treatment of an acquired abdominal hernia in a polar bear (Thalarctos maritimus).

A heart rate radio-transmitter was surgically implanted in the abdomen of a captive adult male polar bear (Thalarctos maritimus), but within five weeks a purulent discharge was observed at the incision site. The transmitter was surgically removed along with many fragments of the fractured encapsulation material. The skin incision healed, but a large hernia remained. Repeated localized trauma to the hernia sac necessitated surgical repair.

Evaluation of xylazine for chemical restraint of captive arctic wolves.

Xylazine at dosages of 2.7 to 3.9 mg/kg of body weight was administered to 23 captive arctic wolves. The optimal dosage was higher for excited and socialized adults and lower for juveniles than for unexcited unsocialized adults. Mean time to initial effect was 2.5 minutes and mean time to sternal recumbency was 3.7 minutes. Maximal effect was achieved within 15 minutes, with adequate sedation lasting 30 to 60 minutes. Mean recovery time was longer for old (greater than 7-year-old) adults than for young (2- to 3-year-old) ones (2.4 vs 1.7 hours). Induction of and recovery from barbiturate anesthesia was smooth and quiet. Although a few adverse reactions were found, the use of xylazine with physical restraint was an excellent combination for many clinical procedures.