SEMINAL VESICULITIS AND ORCHITIS CAUSED BY BRUCELLA-ABORTUS BIOVAR-1 IN YOUNG BISON BULLS FROM SOUTH-DAKOTA

Specimens of blood, lymph nodes, spleens, and genitalia were collected at slaughter from seven 3- and 4-year-old male bison that had recentl y become seropositive for brucellosis. The animals were from a captive herd of approximately 3,500 bison located in central South Dakota. Br ucella abortus biovar 1 was isolated from 2 or more specimens from eac h of 5 bison. Severe necrotizing and pyogranulomatous orchitis was pre sent in 1 testicle from 1 bull, and 4 animals had mild to marked semin al vesiculitis. Immunohistochemical staining labeled organisms in semi nal vesicles and the testicle with orchitis. Ultrastructurally, intact bacilli were present in cytoplasmic vacuoles of some macrophages; oth er macrophages contained intracytoplasmic aggregates of calcified cocc obacilli.