Potential source of human exposure to Mycobacterium bovis in Burkina Faso, in the context of the HIV epidemic

Objective: To identify potential sources of human Mycobacterium bovis infection in Bobo-Dioulasso, Burkina Faso.
Methods: A tuberculin survey among 174 cattle was performed. Mycobacteriologic identification in 64 samples of pooled milk, and in 199 tissue samples collected from the slaughterhouse of Bobo-Dioulasso, Burkina Faso, was also done. We retrospectively analyzed the distribution of tuberculosis (TB) cases on 1140 clinical records according to professional occupation and to ethnic group. The frequency of pulmonary and extrapulmonary TB was related to potential exposure and route of transmission of M. bovis from animals.
Results: Out of six herds (total 170 bovines), only one was free of any positive tuberculin test. Among 199 bovines which had been slaughtered over four consecutive nights, 38 (19%) had morphologic lesions suggestive of TB; 17 (45%) of those were positive for acid-fast bacilli by microscopic examination on one of their lesions, and 20 samples (53%) presented a positive culture for a pathogenic mycobacterium, including M. bovis and M. tuberculosis. In the retrospective analysis, Peuls more frequently had a pulmonary form of disease. This may be related to the route of transmission.
Conclusions: Attention has to be paid to human TB of bovine origin in Burkina Faso. The identification of M. tuberculosis in milk and in tissue samples raises the question of the transmission of TB from humans to cattle.