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 (�2 = 32.3, P < 0.0001); age
group (�2 = 11.47, P < 0.05); and reproductive status (�2 = 10.9, P < 0.05). The herd
prevalence was significantly associated with feeding practices (�2 = 6.6, P < 0.05)
and respiratory signs (�2 = 8.7, P < 0.01). A significant (�2 = 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.