Epidemiological status of bovine tuberculosis in the Federal District of Brazil

Considering the implementation of the National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis (PNCEBT) in 2001, and the need to determine the epidemiological status of animal tuberculosis for future evaluation of the effectiveness of the measures laid down, the objective of this study was to estimate the prevalence and identify risk factors of bovine tuberculosis in the Federal District (DF) of Brazil, as well as to provide an input for the strategic management of PNCEBT. Field testing and data collection was carried out from February to December 2003. The DF was considered a single epidemiological region owing to the small number of existing farms, and the absence of significant differences between the region's farming enterprises, which would justify the stratification of the regional sample. A total of 278 farms were randomly sampled from the local registry database of bovine farms with reproductive activity, in which 2,019 adult cows were tuberculin tested. Only one sampled animal had a positive result, using the comparative cervical tuberculin test, resulting in a bovine tuberculosis prevalence of 0.05% [95% CI: 0.0-0.4%]. The herd-level prevalence of bovine tuberculosis in the DF was estimated as 0.36% [95% CI: 0-2.0%]. The analysis of risk factors was impaired by the results obtained, as the number of cases did not allow for this kind of analysis. Cattle farming in the DF is predominantly aimed at dairy production; however, it is characterized by the presence of small low milk yield herds, which may not favor the introduction and persistency of infection of Mycobacterium bovis. Health authorities from the DF perform surveillance for bovine tuberculosis and maintain the need for tests for the movement of bovines for breeding and those animals destined for any form of animal gathering, especially auctions. Therefore, it is likely that the DF has good conditions for successfully implementing the PNCEBT.