HIV/AIDS and its implications for the control of animal tuberculosis.

The HIV/AIDS pandemic is associated with a number of opportunist mycobacterial infections, principally tuberculosis and disease due to the avian tubercle bacillus, Mycobacterium avium. Tuberculosis occurring early in the course of HIV infection is usually caused by M. tuberculosis. However some cases are due to the bovine tubercle bacillus, M. bovis, which, in turn, is transmissible from man to animals, principally by the aerogenous route although the majority of cases in man are non-pulmonary. These two mycobacterial species may be differentiated by means of a set of simple tests. The quality and quantity of information on the world-wide distribution and prevalence of bovine and human tuberculosis due to M. bovis is not uniform. There is a notable paucity of information from the tropics but available reports suggest that there are significant levels of bovine tuberculosis. If correct, this information has serious public health implications in the light of the current HIV/AIDS epidemic. Urgent investigation is required so that appropriate control measures can be instituted where indicated and possible. The avian tubercle bacillus is a very common opportunistic pathogen in the late stage of AIDS but infection leading to disease is extremely rare in healthy, HIV-negative persons. Because of its widespread environmental distribution, infection by this pathogen cannot be prevented.