By the end of 2020 the AIDS pandemic will have killed over 50 million people, making it the worst outbreak of infectious disease in recorded history. (Or perhaps the second worst, depending how one evaluates the death toll from the Spanish flu epidemic of 1918-19.)
The closest animal relative to HIV-1 (the pandemic AIDS virus) is a simian immunodeficiency virus (SIV) found in the common chimpanzee . There are many SIVs in nature, but these viruses are naturally found only in African primates.
For several years now, there have been only two really viable theories about how this chimp virus might have arrived in humans, and how the AIDS pandemic began.
One theory, the “cut hunter” or “bushmeat” theory, has it that AIDS got started after a hunter from southern Cameroon got infected with chimpanzee SIV while cutting up a chimp for the pot. This theory is non-controversial, but it has many problems and flaws. Most particularly, it has difficulties trying to explain the location of the earliest AIDS cases, which were all in the then-Belgian Congo (nowadays the Democratic Republic of Congo), over 400 miles to the south.
The second theory, the “oral polio vaccine” or “OPV” theory, has it that AIDS began after an experimental OPV that had been cultured in chimpanzee cells was given to nearly a million Africans from the Belgian Congo (DRC), Burundi and Rwanda in the latter half of the 1950s. This hypothesis is rejected by many medical scientists, (including those who prepared and administered the vaccine). There is concerted opposition to the theory from those who publish and write in Nature and Science, the world’s two leading scientific journals.
However, undertanding how a disease began involves not only theoretical calculations (like those of the molecular biologists who claim that by examining the genetic sequences of different strains of HIV-1, they can back-calculate the virus to a start-date such as 1931, or 1907). It also involves having an understanding of the history of relevant events in the past. And in fact the OPV theory of AIDS origin is the theory that is supported by most of the available historical and scientific evidence.
I believe that the OPV theory explains how AIDS emerged, with such devastating effect, in Man. You will find much of the information that supports this view (as well as much of that which opposes it) on this web-site.
Ed Hooper, May 19th, 2020