Impact of present control methods on the problem of tuberculosis.

In spite of the considerable efforts that have been made to control tuberculosis in developing countries in the last three decades, the decline in the global epidemiologic problem has been slow. It is now realized that the possibility of rapidly influencing the tuberculosis problem in these countries with the present control technologies has been overestimated. It is clear that bacille Calmette-Guérin (BCG) vaccination, even in places where a high efficacy was demonstrated, does not substantially influence the chain of transmission. Case management, including bacteriologic diagnosis and chemotherapy, is a complex technology. Although it is potentially effective for the reduction of mortality and the risk of infection, there are many difficulties for its efficient application in developing countries. Although there should be no hesitation in the application and full utilization of what is already known, a major thrust in research may generate ways of accelerating the control of tuberculosis in developing countries. Without new developments in technology for tuberculosis control, the goal of worldwide control has still a long way to go.