Tuberculosis and HIV/AIDS: epidemiological and clinical aspects (world perspective)

Human immunodeficiency virus (HIV) infection is the most powerful known risk factor for progression from latent infection with Mycobacterium tuberculosis to active tuberculosis (TB) disease. The worldwide HIV epidemic has affected TB in every aspect: immunopathology, epidemiology, diagnosis, treatment, and prevention. Of the 42 million people infected with HIV worldwide, more than a quarter of them are also infected with TB, and most live in countries with limited resources for health care in Africa and Asia. This chapter emphasizes HIV-associated TB in resource-limited settings. TB-infected persons with HIV-associated immunosuppression progress to TB disease at a rate of up to 10% per year. Standard TB diagnostic tools have diminished sensitivity in HIV co-infected cases. Standard TB treatment regimens may be less effective, particularly those that do not use a rifamycin throughout. Treatment is further complicated by toxicity, malabsorption, drug-drug interactions and immune reconstitution paradoxical reactions. TB control in the United States was destabilized in part by the HIV epidemic in the early 1990s; massive political will and resources were required to rebuild the public health infrastructure. Africa, Asia, and potentially the former Soviet Union are facing even greater destabilization of TB control due to the dual burden of disease and limited resources. An international response has been initiated but will require even greater political will and resources.