The Acquired Immunodeficiency Syndrome (AIDS) was recognized in mid-1981, in the USA, from the identification of a high number of adult patients of the sex male, gay, and residents of San Francisco or New York, who had Kaposi's sarcoma, Pneumocystis carinii pneumonia, and system compromise immune. All these facts converged to the inference that it was a new disease, not yet classified, with a probably infectious and transmissible etiology.
In 1983, the etymological agent was identified: it was a human retrovirus, currently called Human Immunodeficiency Virus, HIV-1, which was previously called LAV and HTLV-III. In 1986, a second etymological agent was identified, also a retrovirus, closely related to HIV-1, called HIV-2. Although the origin of HIV-1 and 2 is uncertain, a large family of related retroviruses is known to be present in non-human primates in sub-Saharan Africa.
All members of this retrovirus family have a similar genomic structure, showing homology around 50%. Furthermore, they all have the ability to infect lymphocytes through the CD4 receptor. Apparently, HIV-1 and HIV-2 started infecting men several decades ago. HIV-1 has been shown to be more virulent than HIV-2. numerous non-human primate retroviruses found in Africa have shown great similarity to HIV-1 and HIV-2. The simian immunodeficiency virus (SIV) present very frequently in African green monkeys is very close to HIV-2, suggesting that both evolved from a common origin. For these facts, it is assumed that HIV has an African geographic origin and that its dissemination is due to the characteristics of contemporary society.
STDs - Diseases and Health - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/doencas/origem-epidemia-de-hiv.htm
