The global aspects of tuberculosis and HIV infection.

HIV infection is the only factor which has been able to disturb the balance between the tubercle bacillus and man, in the absence of man-made interference. The impact of HIV infection on the epidemiological situation of tuberculosis is so large that, under certain conditions, the tools available at present for tuberculosis control will fail to restrain the increase in the incidence of tuberculosis caused by HIV infection. It is to be seen to what extent an efficient control programme in developing countries will be able to contain the transmission of tuberculosis infection, in particular the risk of tuberculous infection. The current risk of tuberculous infection and its trend is the most decisive factor in containing the deterioration of the epidemiological situation of tuberculosis in developing countries in the future, caused by HIV infection. In countries with high prevalence of both tuberculous and HIV infections it is imperative to achieve and maintain a high cure rate of all diagnosed smear-positive tuberculosis cases, with short-course chemotherapy. Since many tuberculosis cases among HIV-infected persons are smear-negative but culture positive, or smear-negative and culture-negative, or culture-positive or culture-negative, it is necessary, whenever possible, to improve case detection of smear-negative tuberculosis cases through screening by X-ray of the chest patients suspected of having tuberculosis, and to examine those with a pathology on the X-ray by microscopy and if possible, by culture for the tubercle bacilli. Research on the interactions of HIV and tuberculous infections is urgently needed.