Brucella ovis infection in two flocks of sheep.

Brucella ovis infection could not be eradicated from two flocks of sheep despite serologically testing and culling the infected rams for four years. The hypothesis that the ewes played a major role in the maintenance of the infection in both flocks was investigated by using serological, bacteriological and pathological criteria. Specific antibodies against B ovis were demonstrated in 71 ewes in the two flocks. Forty-four of the seropositive ewes were slaughtered for bacteriological and pathological studies and B ovis was isolated from 16 of them; the uterus was the target organ of the infection, although extrauterine infection was also demonstrated in some of the infected ewes.