Don't eat monkeys

HIV is generally accepted to be a descendant of the Simian Immunodeficiency Virus (SIV) from African apes and monkeys, since monkeys from Asia or the Americas don’t carry any strain of SIV that could cause HIV in humans.
A study presented in 2000 at the Conference on Retroviruses and Opportunistic Infections suggested that the first human infection of HIV-1 was in West Africa around 1930. HIV-1 is thought to have originated from chimpanzees and been transferred into humans through the butchering and consumption of monkey meat, NOT by monkey sex as commonly thought.
HIV-2, on the other hand, is most likely thought to have been transferred into humans from sooty mangabeys. The first case was mostly likely in 1940’s in Guinea-Bissau due to consumption of bush meat (again, no sooty sex) and spread by the war of independence from Portugal.
In 2006, a group announced that they had located the SIVcpz strain (that was most likely the origin of HIV-1) in wild chimpanzees in Southern Cameroon.
The moral of the story: don't eat monkeys, you don't know where they've been.