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.

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.

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.

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.