Tuberculosis - Bovine tuberculosis at the animal–human–ecosystem interface

Bovine tuberculosis at the animal–human–ecosystem interface Introduction Bovine tuberculosis is a chronic disease of animals caused primarily by Mycobacterium bovis (M. bovis), a member of the M. tuberculosis complex. The disease is characterized by progressive development of specific granulomatous lesions or tubercles in lung tissue, lymph nodes or other organs. The incubation period ranges from months to years, but acute stages of the disease can develop during the course of infection, when lesions progress rapidly. Bovine tuberculosis is an important disease in livestock and in a wide range of wild animal species worldwide. Bovine species, including bison and buffaloes, are particularly susceptible to the disease, but nearly all warm-blooded animals can be affected. M. bovis is also known to affect humans, causing a serious public health problem when it becomes endemic. Similar to the human form of tuberculosis, bovine tuberculosis is commanding growing attention from the international community. This is because of the serious increase in the number of infected herds and the subsequent effect on animal production, combined with the significant impact of M. bovis infection on public health, and the permanent threat of infection from animal reservoirs. Despite the long history of disease recognition, the epidemiology of M. bovis is not well understood, especially in wildlife. In some developed countries, the disease has been eliminated from the livestock population, but in other countries wildlife species have been identified as reservoir hosts, representing a continuous threat and source of infection of cattle and making complete eradication difficult. In less developed countries, the disease is maintained in bovines and continues to cause significant losses in the cattle farming sector, with serious implications for public health, especially where there is no effective surveillance and control programmes are weak or non-existent. In response to the global importance of bovine tuberculosis for both animal and public health, the Food and Agriculture Organization of the United Nations (FAO) has recognized it as a priority infectious disease that should be controlled at the animal–human–ecosystem interface, through national and regional efforts. This article does not aim to provide a comprehensive description of bovine tuberculosis, which can be found elsewhere (Michel, Müller and van Helden, 2010; Thoen et al., 2009), but rather to outline the main features of bovine tuberculosis in cattle and wildlife, the impact of the disease on public health, and perspectives on its control, with particular reference to the situation in developing countries.