Background:  The global burden of HIV and tuberculosis (TB) is immense:  40 million people currently live with HIV/AIDS, and every year there are 5 million new HIV infections and 3 million AIDS-related deaths. TB exacts an equally grim toll with 9 million new TB cases and 2 million deaths each year. There is a strong association between the 2 infections, with 24 million people estimated to be co-infected in 2000. In co-infected persons the annual risk of active TB is 5 to 15%, 50 times higher than in non-HIV infected persons. The dual epidemic is most heavily felt in sub-Saharan Africa. HIV adversely affects TB control efforts, and the case of Malawi is shown as an example. Indirectly, HIV leads to increased case notifications, “hot spots” of TB transmission, stigma, and resultant delay in TB diagnosis, and illness of health care staff, which compromises patient care. Directly, HIV makes TB diagnosis more difficult by increasing the prevalence of smear-negative and extra-pulmonary TB, it increases morbidity through HIV-related disease and adverse drug reactions, it increases case fatality rates and is associated with increased rates of recurrent TB after treatment has been completed.   

Conclusions:  Strategies have been devised to decrease the joint burden of HIV and TB. First, mechanisms need to be established for collaboration between HIV/AIDS and TB programmes. Second, the burden of TB in people living with HIV/AIDS should be reduced by intensified case finding, isoniazid preventive therapy, and TB infection control in health care and congregate settings. Third, the burden of HIV in TB patients should be reduced by counselling and HIV testing, care and support of HIV-related disease, cotrimoxazole preventive therapy, and HAART. The scaling-up of HAART in sub-Saharan Africa may help to decrease case fatality and recurrence rates of TB, and may lead to a decrease in the incidence of TB, provided the difficulties of combining HAART and TB treatment can be resolved. The main difficulties include additive adverse reactions, drug interactions, and management of immune reconstitution disease. The challenge ahead lies in translating TB/HIV strategies into action.