Investigations on the prevalence of bovine tuberculosis and brucellosis indairy cattle in Dar es Salaam region and in zebu cattle in Lugoba area, Tanzania

A study between August 1995 and December 1997 included 343 dairy cattle on 20 farms in the Dar es Salaam region and 2289 zebu cattle on 39 bomas in th e Lugoba area (coast region). The aim was to establish the prevalence of bo vine tuberculosis (Mycobacterium bovis) and bovine brucellosis (Brucella ab ortus). In the single intradermal tuberculin test (SIT), 0.9% (3/343) of th e animals in Dar es Salaam tested positive and 1.2% (4/343) were doubtful. Positive reactors were found in 10% (2/20) of the farms. In the Lugoba area , 0.6% (14/2206) were positive and 6.8% (149/2206) doubtful, positive cases being found in 21% (8/39) of all bomas. In the slow agglutination test (SA T) for B. abortus, 14.1% (48/341) of the serum samples reacted positively i n Dar es Salaam and 2.3% (8/341) were doubtful. Positive SAT reactors were identified on 25% (5/20) of the dairy cattle farms. In the Lugoba area, 12. 3% (273/2221) proved to be positive SAT reactors and doubtful reactions wer e observed in 2.9% (64/2221). SAT-positive animals were detected on 87% (34 /39) of all bomas. The prevalence in single herds in Dar es Salaam varied f rom 4.3% to 5.3% for the SIT and from 2.2% to 50% for the SAT. The prevalen ce in single herds in Lugoba area was between 1.1% and 2.9% for SIT and fro m 1.4% up to 62.1% for SAT. The two cattle populations differed significant ly (p < 0.001) in the prevalence of both bovine tuberculosis and bovine bru cellosis. Two cows that were positive reactors were slaughtered and subject ed to post-mortem examination, and organ samples were bacteriologically cul tured. The occurrence of Mycobacterium tuberculosis was confirmed by polyme rase chain reaction (PCR) in both cows.