Epidemiology of tuberculosis: the impact of HIV and multidrug-resistant strains.

The recent reemergence of tuberculosis in the United States and other developed countries has been attributed to a number of factors including a decreased emphasis on tuberculosis control and immigration. Perhaps the most significant factor is the association of tuberculosis and HIV/AIDS. Infection with HIV greatly increases susceptibility to infection and increases the risk of developing active disease. In addition, progression of tuberculosis can be very rapid in patients with greatly reduced immune function. The increasing incidence of drug resistance is also contributing to the difficulty in controlling tuberculosis. Multidrug-resistance not only adversely affects the patient but contributes to prolonged infectiousness.