I agree that vaccination had something to do with the spread of HIV (although NOT with its actual beginning existance, as such, well, sort of, but not as a deliberate act)
Bushmeat.....small monkeys, gorilla, and our closest two living relatives, the chimp, and the bonobo.
Eaten for a long time, without the spread of virus. At least, in more than a very minor, and not particularly dangerous way. SIV, or simian immunodeficiency virus isn't a particularly dangerous agent to humans although it IS capable of producing infection, this doesn't appear to cause the immune system failure, and persistent infection that HIV does. SIV appears to infect humans, have an acute infectious period, then decline, as the body attacks it.
There is a gene, I cannot name it because the CIA, who invented AIDS, will ki....I mean, because I was reading on endogenous retroviruses at the time (interestingly, its almost certain, that placental mammals would not be here at ALL if it were not for endogenous retroviruses) that appears to determine protection against HIV or SIV, is different in humans vs other primates. Severak mutants have been isolated, its protective against HIV, or SIV...but no mutant found or prepared has conferred immunity against both viruses-its one or the other, SIV or HIV.
If it wasn't for this gene, most likely SIV would be able to selectively target T lymphocytes in the same manner that HIV does.
As most people who know anything about HIV, or anything like that know, a part of the problem, ESPECIALLY with retroviruses, is the speed that they mutate at. Lacking some copy-check mechanisms that DNA viruses use (a retrovirus has an RNA genome, and uses a reverse transcriptase enzyme to make a DNA copy, rather than following the central dogma of genetics, that an organism replicates from DNA, to RNA, to protein end product, not counting of course, enzyme catalysed post-translational modification of proteins)
Lacking those copy-checking mechanisms that otherwise, in DNA viruses proofread the finished viral code, the retrovirus, sacrifices accuracy for vastly superior speed of replication. A retrovirus mutates very quickly, speedily inactivating vaccines, or treatments directed against viral infection.
SIV is only infectious in its acute stage, quickly being attacked and rendered noninfectious by the host human's immune defenses....
That isn't a very long window of infection, and its not a highly infectious virus, not in humans, so, think, for the past few hundred thousand years or so that truly human hominids existed, yes, people will have caught SIV infections many, many times, and probably not known it (well of course they wouldn't know what a virus even was for most of that time, but thats not what I meant)
They would have only limited chance to pass on the infection, either via sexual contact, maybe if one human bit another in a fight, or the chance occurence of the same cutting implement cutting the african with an SIV infection in the acute, infectious stage, cutting another african. So no real chance, even if (and its every bit possible it has, several times, or many times over, in fact, we will never know what could happen, but didn't) it transferred hosts, it never had the chance to do so en masse, as has been facillitated by decreased monogamous relationships, increased travel (isolated villages, and tribes, of course never have the chance to pass on even a highly infectious, only slowly, or nonlethal viral agent if they never SEE anybody else, or do so only rarely for trade purposes), and above all, aside from the unprotected sex and the poofters....INJECTIONS!
They didn't sterilize needles then, nor did they have disposable syringes, they used the same ones again, and again, and again, and again. Bingo. There, is your transmission opportunity for that rapidly mutating retrovirus, which in a handful of hosts so infected (there are different strains of HIV, most are found very, very seldom outside of africa), this virus, once SIV...now HIV...just got its plane ticket and its in flight meal.