Causative agent: Brucella abortus
B. abortus causes disease in cattle, sheep, goats and bison (9). It has been reported to cause disease in bison in Canada and the United States (11,12,13,14,15,16,17).
Clinical signs:
In male bison, B.abortus infection causes orchitis, seminal vesiculitis, and epididmytits (18). In female bison it causes placentitis and abortion (11, 18).The frequency of abortion in bison may not be as high as in cattle. It has also been reported to cause abscesses and chronic septic arthritis in bison of either sex (11, 18).
Diagnosis:
In Canada, the Canadian Food Inspection Agency (CFIA) maintains a monitoring program for brucellosis and tuberculosis in bison. All bison herds must obtain a negative herd status. This is achieved by testing all bison on the farm that are over 18 months of age. After a herd test is found to be negative the farm will receive a negative herd status remaining in effect for 5 years. The farm’s negative herd status may be extended by testing 10% of the total herd per year. If the negative herd status is allowed to expire the farm will be restricted from moving bison off the farm, until a negative herd status is regained.
Treatment:
In Canada, brucellosis is not treated. The CFIA administers a test and slaughter program for brucellosis. Bison that are infected or test serologically positive for B.abortus are slaughtered.
Control:
The Canadian government through the CFIA administers a surveillance program for detecting outbreaks of B. abortus infection. The program includes on farm testing, slaughterhouse testing, and monitoring of the movement of bison. Vaccination of bison against brucellosis is not permitted in Canada because vaccinated animals cannot be distinguished from infected animals by serological testing.