HIV Infection

Testing for HIV became available in the United States in 1985. Amazing gains in the understanding and treatment of HIV have been made during the past 25 years. HIV and other retroviruses cause a frequently symptomatic primary infection followed by a relatively asymptomatic period lasting months to years and a final stage of overt disease in most people. There are 2 types of HIV: HIV-1 and HIV-2. Most reported cases of HIV disease around the world are caused by HIV-1. HIV-2 is found predominantly in western Africa. Although HIV-1 and HIV-2 are clinically indistinguishable and have identical modes of transmission, HIV-2 appears to be less easily transmitted than HIV-1 and slower to progress to AIDS. Epidemiology, diagnosis, and treatment of HIV are also reviewed.