EVALUATION OF PROCEDURES FOR THE DIAGNOSIS OF BRUCELLA OVIS INFECTION IN RAMS

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Abstract
Procedures for the diagnosis of B. ovis infection in rams were evaluated by examining 10 rams artificially infected by preputial inoculation. Observations were undertaken at weekly intervals for 1 yr to follow changes in clinical, bacteriological and serological findings. Clinical lesions were detected in 1 ram 3 wk after inoculation and in all rams by 8 wk; lesions were undetectable in 3 rams at the completion of the trial. The presence of inflammatory cells in semen samples was the earliest indication of infection, being demonstrated in 2 rams at 2 wk and in all rams by 8 wk; subsequently 86% of samples were positive. B. ovis was detected in semen smears from 3 rams at 4 wk but only once in all rams (at 27 wk); overall, 52% of semen smears were positive from 4 wk onwards. B. ovis was cultured from semen of 5 rams after 4 wk and from all rams at 5 wk; thereafter 97% of samples were positive. All rams developed significant titers to the CFT [complement fixation test] by 2-9 wk; thereafter the CFT was a reliable indication of infection in 6 rams, highly suggestive in 3 and unreliable in 1. By 8-10 wk, all rams developed significant titers to the IHA [indirect hemagglutination assay] which were then maintained in all rams for the remainder of the trial.