Tuberculosis - : new light from an old window

Tuberculosis is still recognized worldwide as a significant animal health risk, primarily in domestic cattle. The unusually extensive host range for the aetiological agent, Mycobacterium bovis, includes most farmed and wild animal species and also humans. All species are not equally susceptible to M. bovis; some are considered spillover hosts, whilst other hosts maintain and transmit infection. Therefore, despite considerable success in controlling this disease in cattle populations in many developed countries, tuberculosis remains a sufficiently important economic problem in others. In developing countries, such as Africa, M. bovis also affects farmed and wild animals, with accompanying economic and social consequences. However, unlike developed regions of the world, the extent of its involvement in human tuberculosis is not precisely known. The impact of this zoonotic infection on the high-risk group with concomitant HIV/AIDS infection is causing growing concern. This is a complication in the recent global resurgence of human tuberculosis, which has also precipitated renewed research interest. There is considerable new information about the M. tuberculosis complex organisms emanating from research collaborations on animal and human tuberculosis. This paper highlights some developments in recent years, which have enhanced understanding of the pathogenesis and epidemiology of bovine tuberculosis and there now is a better opportunity than ever before to control and eradicate this infection through appropriate strategies for diagnosis and vaccination.