[A very current aspect of the fate of infectious diseases: tuberculosis, leprosy and opportunistic mycobacteria].
The human mycobacterial diseases, such as tuberculosis and leprosy, are chronic infectious diseases and have been present for a long period of time with human beings. Clearly tuberculosis and leprosy have been on the wane long before effective therapy was introduced, each of them having a natural epidemic evolution, with onset, peak and decline. Such decline was apparently accelerating in recent decades, due to individual and collective measures aiming at controlling the diseases, and it gives the hope of their possible elimination in the early XXIe century. If for leprosy recent data seems to indicate a realistic hope, such one has been destroyed for tuberculosis, since worldwide reemergence of cases occurs, which was associated with non application of control measures and occurrence of the HIV infection. Such coinfection leads to immunodeficiency that increases the risk of tuberculosis and the development of disseminated opportunistic mycobacterioses, mostly due to M. avium. An increased persevering action in the control measures and the development of new ways of research on mycobacterial infections are even more necessary if one will master such devastating plaques.