The disease was officially called GRID - Gay Related Immune Deficiency, though it was often called the "gay cancer." With next to no funding, and the US government unwilling to touch "gay issues" with a ten foot pole, a small group of dedicated researchers thrust all they had into finding the cause.
Researchers soon figured out that the disease was sexually transmitted, and began taking detailed sexual histories of all those afflicted. One name came up over and over, the name of the man who would become known as patient zero, Gaeton Dugas. This marked the first time the term patient zero was used.
Dugas wasn't, of course, the first person to have AIDS. He was just an incredibly promiscuous flight attendant who traveled all over the country, infecting men wherever he went, even after doctors told him that the disease killing him was sexually transmitted.
It's likely impossible to find the real patient zero, of course, but scientists have come shockingly close.
See, AIDS had been in America since long before 1981, when it was discovered. Scientists looked through countless medical records for AIDS-related infections, like pneumocystis pnemonia and Kaposi's sarcoma. They found a likely case in England 1959. And another likely case in Chicago in 1961.
All of this is just speculation though. To find out for sure where the virus came from, they needed to look at the virus itself. So they dug up blood and tissue samples from every known and suspected case that they could. Then they looked at mutations in the virus' structure - see, viral mutations happen at a really steady rate, creating a trail leading back to the earliest cases - the fewer the mutations, closer the source. Scientists found that the disease took hold in the US after arriving from Haiti in 1966 (earlier cases may have existed, but not been passed on). And it got to Haiti from Africa. In Africa, scientists were actually able to locate blood and tissue samples from two individuals, both of whom had HIV, both from around 1960. Scientists could then look at the two samples and determine, from the differences between them, that the disease had made the jump from chimp to human around 1908 in southeastern Cameroon. The likeliest scenario is that a bushman killed a chimp infected with simian immunodeficiency virus and cut himself in the process.
Even though it's not in the headlines as much anymore, AIDS is still killing people all over the globe. Wanna do something about it? Here are some charities that could use our help.
Info from Randy Shilts' And the Band Played On, aids.gov, and a Radiolab story also called Patient Zero.