The Mycobacterium tuberculosis Complex in Africa

Abstract

The Mycobacterium tuberculosis complex (MTC) comprises distinct lineages of clonally evolving organisms and includes a number of genotypically and phenotypically defined species, many of which are associated with specific animal hosts. Mycobacterium bovis is the most common cause of tuberculosis (TB) in animals in Africa, and it appears to have been introduced onto the continent with the movement of humans and their domestic livestock. However, a lesser known cause of animal TB is a lineage of the MTC that had its early origins in West Africa. This lineage is represented by a number of species including the chimpanzee bacillus, isolated from a chimpanzee (Pan troglodytes) in Côte d'Ivoire; the dassie bacillus, which causes TB in rock hyraxes (Procavia capensis); M. mungi, which infects banded mongooses (Mungos mungo); and M. suricattae, which has been isolated from meerkats (Suricata suricatta). These members of the MTC as well as other rare causes of TB in animals in Africa are reviewed, namely, M. africanum and M. orygis. The value of careful genotyping of mycobacterial pathogens is discussed.