Mycobacterium bovis as a zoonosis in the Kruger National Park, South Africa

SETTING: The Kruger National Park (KNP), Mpumalanga Province, South Africa. OBJECTIVE: The prevalence of tuberculosis caused by Mycobacterium bovis exc eeds 70% in African buffalo in the southern region of the KNP. Inter-specie s transmission (lion, cheetah, baboon, antelope) has also been confirmed. R egular culling of emaciated buffalo and processing of meat and hides consti tute routine control policy. Following extensive media coverage of the prob lem, public health concerns about the transmission of M. bovis to humans, i ncluding visitors to the KNP,prompted this investigation. DESIGN: The study was designed to determine the prevalence of infection and /or active disease due to M. bovis among KNP employees selected from three defined risk groups based on occupation category. RESULTS: Of 206 persons screened for active disease by sputum bacteriology, two persons with disease due to M. tuberculosis were identified. No isolat e of M. bovis was found. Differential skin testing using three antigens fai led to show any degree of M. bovis infection risk, even among high risk occ upations. Reasons for these results are discussed. CONCLUSIONS: Bovine tuberculosis was not indicated as an occupational zoono sis in the KNP, nor was aerosol transmission implicated as a mechanism for human infection. Concerns about the public health implications of tuberculo sis in buffalo in the KNP have therefore not been validated.