Bovine tuberculosis in a free-ranging mule deer (Odocoileus hemionus) from Montana.

A survey of 41 mule deer (Odocoileus hemionus) and three white-tailed deer (O. virginianus) for bovine tuberculosis was conducted on a Montana (USA) cattle ranch from 2 November 1993 through January 1994. Gross and microscopic lesions typical of tuberculosis were present in tonsil and lymph nodes of the head, thorax, and abdomen of one adult female mule deer. Additionally, a single microgranuloma considered morphologically suggestive of tuberculosis was present in one lymph node of the head of a second mule deer. Mycobacterial isolates from lymph nodes of the head and thorax of the first deer were identified as Mycobacterium bovis.

Immunohistochemical detection of Tritrichomonas foetus in formalin-fixed, paraffin-embedded sections of bovine placenta and fetal lung.

An immunohistochemical technique using a monoclonal antibody was evaluated as a diagnostic tool to specifically label Tritrichomonas foetus in formalin-fixed, paraffin-embedded sections of placenta and fetal lung from bovine abortions. Trichomonads were demonstrated in tissues from each of 12 abortions due to T. foetus and none of 15 abortions due to other or unidentified causes. Moderate to marked background staining occurred only in severely autolyzed tissues from T. foetus-infected fetuses. The antibody faintly labeled 1 of 3 other species of trichomonads (Trichomonas gallinae) but did not label other protozoa, bacteria, or fungi tested.

Abortion caused by Brucella abortus biovar 1 in a free-ranging bison (Bison bison) from Yellowstone National Park.

A near-term aborted bison (Bison bison) fetus was collected near Old Faithful geyser in Yellowstone National Park, Wyoming (USA). On necropsy, the fetus liver had a small capsular tear, and there was a small quantity of blood in the peritoneal cavity. Microscopic lesions included mild, purulent bronchopneumonia and mild, multifocal, interstitial pneumonia. Brucella abortus biovar 1 was isolated from fetal abomasal contents, lung, and heart blood.

Range of heartworm (Dirofilaria immitis) infection in Montana dogs.

The serological presence of heartworm in dogs of Montana was studied in a 3-yr survey. Serum samples were provided by veterinary practitioners throughout Montana or were submitted to the state diagnostic laboratory. Sera from 3,490 dogs were tested using an enzyme-linked immunosorbent assay (ELISA) for circulating adult heartworm antigen. Twenty-four serum samples were positive for heartworm antigen. Two were from dogs that had never been outside the state. Nineteen additional positive dogs, 7 of which presumably had never been out of the state, were reported through correspondence with veterinary practitioners. Because suitable vectors for Dirofilaria immitis exist in Montana, there is potential for propagation of heartworm.

Mycobacterium bovis infection in North American elk (Cervus elaphus).

A naturally occurring outbreak of Mycobacterium bovis infection in captive wild elk (wapiti) in Montana was confirmed by mycobacteriologic examination. Twenty-eight of 143 elk responded to M. bovis purified protein derivative (PPD) tuberculin injected intradermally in the cervical region (SCT). The results of comparative cervical tuberculin skin tests conducted within 9 days of SCT revealed greater responses to M. bovis PPD tuberculin than to M. avium PPD tuberculin in 23 of 28 elk responding. At necropsy, several grossly visible tuberculous lesions were observed in the parenchyma of the lung, thoracic lymph nodes, and submandibular lymph nodes. Microscopic examination of appropriately stained tissue sections revealed the presence of granulomatous lesions containing acid-fast bacilli. An enzyme-linked immunosorbent assay (ELISA) was developed using a sarkosyl extract of M. bovis (antigen) and peroxidase-labeled protein G (conjugate); reactions were detected in the sera of 8 of 9 elk responding to M. bovis PPD tuberculin. Lymphocyte blastogenic assay responses were detected using M. bovis antigens in 7 of 9 elk positive on skin tests using M. bovis PPD.

Chlamydial-caused infectious keratoconjunctivitis in bighorn sheep of Yellowstone National Park.

An epizootic of infectious keratoconjunctivitis occurred in bighorn sheep (Ovis canadensis) in Yellowstone National Park during the winter of 1981-82. The causative organism was identified as Chlamydia sp. Mortality related to the epizootic was approximately 60% of an estimated 500 bighorn sheep in the northern range population. The infection probably affected all sex and age classes, but field surveys of live animals and mortality suggested that mature rams died disproportionately. Limited field observations the following winter on individuals having both normal and cloudy-appearing eyes suggested that half of the bighorns then present on the core units of winter range had contracted the disease and survived. By 1988, there were about 300 bighorn sheep in the population.

Disseminated geotrichosis in two dogs.

Disseminated geotrichosis was diagnosed at necropsy of 2 unrelated dogs from the same household. Clinical signs of disease included fever, coughing, anorexia, listlessness, polydipsia, and dyspnea. The duration of clinical illness was less than 2 weeks. Pathologic findings in both dogs were similar and consisted of pyogranulomatous pneumonia, hepatitis, and nephritis. Geotrichum candidum was identified by fluorescent antibody technique.

Fetal and placental lesions in bovine abortion due to Tritrichomonas foetus.

Laboratory records and histologic material from 13 cases of naturally occurring, early- to late-term bovine abortion due to Tritrichomonas foetus were examined. Placentitis was present in all placentas. Pyogranulomatous bronchopneumonia was in six of the 11 lungs which were examined. Trichomonad organisms were demonstrated within the placental stroma in all cases and free or phagocytized in pulmonary airways in seven cases.

Isolation of enterotoxigenic Bacteroides fragilis from humans with diarrhea.

Enterotoxigenic Bacteroides fragilis was isolated from stool specimens of 8 of 44 diarrheic individuals (ages, 4 months to 69 years). The individuals had watery diarrhea and intestinal cramping; and infants had hyperthermia, vomiting, and blood in the stools. No recognized enteric pathogens were detected in seven of the eight diarrheic individuals positive for enterotoxigenic B. fragilis. The bacterium produced an enterotoxin detectable in concentrated broth that supported bacterial growth. Fifteen adult rabbits with ligated ceca developed fatal enteric disease following intraileal injection with 5 x 10(9) CFU of enterotoxigenic B. fragilis. Conversely, eight control rabbits injected with nonenterotoxigenic B. fragilis remained clinically normal. As few as 5 x 10(3) CFU of enterotoxigenic B. fragilis caused fatal enteric disease in the rabbit model. Disease in rabbits was characterized by mucoid, often hemorrhagic, diarrhea. The bacterium colonized the caudal small intestine and the colon of the rabbits and caused moderate to severe necrotizing colitis. Enterotoxigenic B. fragilis is widespread in the intestinal tract of diarrheic humans and is enteropathogenic in adult rabbits with ligated ceca. Its possible role in the enteric disease complex merits further study.

Parasitic ulcerative ventriculitis in mallards (Anas platyrhynchos).

Natural infections of Streptocara crassicauda and Streptocara incognita were diagnosed in four mallards (Anas platyrhynchos) from Red Rock Lakes National Refuge, Beaverhead County, Montana. Lesions at the junctions of the gizzard and proventriculus were associated with the nematodes, and resulted in debilitation, emaciation and death.

Pathogenesis of infection with Sarcocystis rauschorum (Apicomplexa) in experimentally infected varying lemmings (Dicrostonyx richardsoni).

This study describes the sequential formation of lesions associated with the endogenous development of Sarcocystis rauschorum (Apicomplexa: Sarcocystidae) in varying lemmings, Dicrostonyx richardsoni. Lethal doses of sporocysts (greater than 500) were orally administered to lemmings examined 1-6 days postinoculation (DPI) whereas sublethal doses were administered to lemmings examined subsequently. Transient necrosis and purulent inflammation, in association with precystic merogony, occurred in the liver by 4.5 DPI, peaked at 6 DPI and subsided beginning at 11 DPI with the liver returning to normal by 15 DPI. Cyst formation in skeletal and cardiac muscle was associated with purulent inflammation and sarcolemmal proliferation beginning at 9 DPI. These lesions persisted to 42 DPI. In addition, multifocal nonsuppurative meningoencephalitis was present in six of 11 infected lemmings examined between 11 and 15 DPI.

Pancreatic duct adenoma and strangulation of the small intestine in a California sea lion (Zalophus californianus).

A 16 year-old female California sea lion (Zalophus californianus) died in a zoological garden following a period of insidious weight loss. Necropsy revealed a loop of intestine strangulated by a fibrous ring connected to a pancreatic mass. Histopathologic diagnosis of the latter was pancreatic duct adenoma.