[Tuberculosis semper viva].

At the end of the twentieth century tuberculosis still has the attributes of a multiple, difficult to diagnose, and frequently treacherous disease which is difficult to treat. Due to its high prevalence in the developing countries and due to new medical and sociological elements associated with tuberculosis in economically developed countries with a low prevalence, tuberculosis still remains a paradoxical memento of medical science and practice. We know its etiological agent, treatment and principles of its control and despite this we must assume that it will persist in the human population for at least the period of one human life.