I actually read an article in Rolling Stones in the early 90's that linked the origin of the AIDS to the Sabin live polio vaccine. It also pointed out that Sabine (who was still alive at the time) would not allow testing of those stock virus samples that he still had in his possession for the AIDS virus.
It's also quite possible that the reason that the AIDS virus hit Africa so hard is that monkey's are a staple meat for many villages there (my theory-- unsupported). It was pointed out not to long ago, in the media, that the ebola virus outbreaks were finally pin-pointed to villagers eating infected dead primates they found in the jungle and then contracting ebola. So, if they routinely eat primates and contract viruses such as ebola, then is it a logical leap to assume that if one habitually dines on primates who are carriers of SIV, you would ingest the virus dna that would lay dormant and replicate and mutate until it's in a form to infect humans???