There is some thought (and scientific evidence to support same) that AIDS actually showed up in the US in 1954, though it was not recognized until June 5, 1981.
HIV has been detected in preserved historical blood samples as far back as *1959*.
I remeber reading years ago that AIDS was known to exist back in the 1950's. However, in order to become an epidemic, all it needed was for one infected promiscuous gay man to enter a bathouse, and it was "game over".
The last genetic studies I remember reading traced HIV back to 1939 or thereabouts in Africa. But that date comes from assuming constant mutation rates, which is not always a valid assumption.
"Shilts concentrates on a few people who were central to the AIDS epidemic. One such person was a Quebecker Airline Steward by the name of Gaetan Dugas, the so-called Patient Zero. Dugas was not the first person to be infected with AIDS (or detected as such). But Dugas was seen as the reason why AIDS was able to spread like wildfire across countries and continents. Calling Dugas promiscuous is an understatement. It is said that he would indulge in several thousand partners from the late 1970s until 1984. When his condition became diagnosed as GRID (Gay Related Immuodeficiency Disease) or more popularly known then as "Gay Cancer" (as AIDS was known as before it became obvious that it was not just a gay disease), Dugas continued to sleep with random partners. He would even visit clubs and after finishing his interludes, would turn the lights up and boast he had passed the cancer onto his partner, ghoulishly exposing his Kaposi Sarcoma lesions and his gaunt face and body. Dugas would eventually become an outcast in the gay community, moving back to Canada where he continued his promiscuity there."