The Global Epidemiology of AIDS

In 1981, the first cases of AIDS were recognized in previously healthy homosexual men residing in the United States. Within just a few years, thousands of cases were recognized in members of other high-risk groups, including injecting drug users (IDUs), hemophiliacs, and recipients of blood transfusions. The diversity of the global AIDS pandemic is also reflected in the heterogeneity of the viral subtypes of HIV. Recent studies have suggested that HIV entered the human population through multiple zoonotic infections from simian immunodeficiency virus (SIV)-infected nonhuman primates sometime in the early to mid-20th century. In 1985, a second human retrovirus associated with AIDS, HIV-2, was identified in West Africa. This virus has been found to have relatively high prevalence rates among hospitalized patients, female prostitutes, and patients who attend sexually transmitted disease (STD) clinics in several countries of West Africa. Sub-Saharan Africa represents the epicenter of the global HIV/AIDS pandemic. HIV/AIDS is now the leading cause of death in some countries of the Caribbean basin.