Who Does It Affect?
Substantial evidence suggests that the burden of M. bovis, the causal agent of bovine tuberculosis, might be underestimated in human beings. Incorrect extrapolation of data from high-income countries and those with low burden of tuberculosis has probably resulted in the misconception that only a small proportion of people have pulmonary and extrapulmonary tuberculosis caused by M. bovis globally. This misconception has resulted in a general insufficient awareness among health-care providers and public health officials regarding the importance of M. bovis as a cause of human tuberculosis. *
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Other MTBC species including M. caprae, M. microti, M. orygis, and M. pinnipedii have been reported to cause ZTB in people.
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While domestic cattle are the principal hosts of Mycobacterium bovis, other domestic livestock and wildlife are also susceptible to infection. Some wildlife species are considered “maintenance” hosts, acting as important sources of infection for livestock. This can be due to their inherent susceptibility to the pathogen or the habitat they occupy in relation to livestock. These include European badgers (Meles meles) in the United Kingdom and Ireland; brushtail possums (Trichosurus vulpecula) in New Zealand; wild boar (Sus scrofa) in the Iberian peninsula; African buffalo (Syncerus caffer) in South Africa; and elk (Cervus canadensis) and white-tailed deer (Odocoileus virginianus) in the United States. Other wildlife species can be considered “spillover” hosts, meaning that they can be infected but do not necessarily play a role in transmission to livestock.**
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(See list of scientific publications about these MTBC species causing ZTB in humans here)
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* Zoonotic tuberculosis in human beings caused by Mycobacterium bovis—a call for action; Olea-Popelka F, Muwonge A, Perera A et al; The Lancet: 30 September 2016
** Roadmap for Zoonotic Tuberculosis, World Health Organization (WHO), Food and Agriculture Organization of the United Nations (FAO) and World Organisation for Animal Health (OIE), 2017