Tuberculosis incidence in developing countries with high prevalence of HIV infection.

OBJECTIVE: To study the impact of the HIV epidemic on tuberculosis (TB) incidence in developing countries. DESIGN: A simple mathematical model is constructed using figures from published reports to estimate the rise of TB incidence as the HIV epidemic expands. METHOD: Two groups with different risk of developing TB are identified: individuals with dual infection of HIV and Mycobacterium tuberculosis and the rest of the population. The model is based on a combination of the incidence and the percentage of TB in these two groups. The expected rise in TB incidence and the percentage of TB cases that will be HIV-positive are plotted against the prevalence of HIV. CONCLUSIONS: Unless appropriate action is taken, TB incidence in developing countries will double as the prevalence of HIV infection reaches 13 per hundred adults.