Bovine tuberculosis on small-scale dairy farms in Adama Town, central Ethiopia, and farmer awareness of the disease

A cross-sectional study was conducted on 378 households, owning 524 head of cattle, to determine the prevalence of bovine tuberculosis (TB) and assess its public health implications. Stratified systematic sampling and a questionnaire were used, in addition to the comparative intradermal tuberculin test, mycobacterial culture and biochemical and drug susceptibility tests. Using a confidence interval (CI) of 95%, the herd and animal prevalences were 15% (11.4%, 18.6%) and 11% (8.32%, 13.68%), respectively. A significant variation in prevalence (P) was observed in regard to herd size (chi2 = 32.3, P < 0.0001); age group (chi2 = 11.47, P < 0.05); and reproductive status (chi2 = 10.9, P < 0.05). The herd prevalence was significantly associated with feeding practices (chi2 = 6.6, P < 0.05) and respiratory signs (chi2 = 8.7, P < 0.01). A significant (chi2 = 8.4, P < 0.01) association was recorded between the presence of reactor cattle and human TB cases in a household. Thirty-five percent (132/378) of the respondents knew about bovine TB while only 32% (121/378) were aware it could be transmitted from cattle to humans. Mycobacterium bovis and M. tuberculosis were isolated from 18.2% and 11.4% (n = 44) of the milk of reactor cows, respectively. In conclusion, the herd and animal prevalences of bovine TB were moderate. The fact that human TB patients and reactor cattle were present in the same household suggests the transmission of mycobacterial species between cattle and their owners, while the awareness of these farmers about bovine TB and its transmission was generally poor.