The natural transfer theory suggests that the Leopoldville man was one of the earliest infectees. It is suggested that the Leopoldville man or his immediate contacts – was a monkey hunter, and had become infected via a monkey bite. On his return to Leopoldville the infection was transmitted forward sexually, gradually spreading through the continent, thence into Haiti and the homosexual population in America. The virus mutated and become more pathogenic in its continued transmission through various hosts and evolved into the various subtypes now known in the world. This theory appeals in a number of ways in that it is somewhat un-researchable beyond this speculation, and leaves the virus’ introduction a matter of chance. Chief objections to this theory are the same as its appealing factors. It is also incredibly bad luck for humanity as a whole, and raises the question that if this method of transmission had happened once, why had it not happened before, and other animal retroviruses not been isolated in human populations? Furthermore, there is the second human retrovirus HIV-2 that would appear to have been introduced from the sooty mangabey (SIVsm) at about the same time? This is incredible chance for two simian retroviruses to be introduced in the same period.

If natural transfer is not the truth, the remaining theories argue that human intervention must have been involved at some level. Edward Hooper has suggested in The River that the source of HIV – the transmission of SIVcpz into humans – occurred as an unforeseen side effect of oral polio vaccine (OPV) campaigns that took place in Africa in the 1950s. Hooper’s case amounts a huge quantity of circumstantial evidence written in over 1000 pages.

Vaccination is the process where small amounts, weakened or dead viruses are introduced into the human body in order to produce an immune response. The immune system thus ‘remembers’ the virus, and when a person becomes infected with a ‘wild’ virus the immune system can respond effectively. Via this method, a number of afflictions and diseases worldwide have been effectively eliminated. However, in order to vaccinate a large population, one needs to grow a lot of viruses, and also a particular culture to grow them in. One highly successful culture is monkey kidney tissue culture (MKTC) which provides a rich reproductive environment for the poliomyelitis virus. This tissue culture was used by a number of vaccine producers, primarily Hilary Koprowski, who established a camp in Lindi, Zaire (now the DRC). This camp kept a number of chimpanzees and other primates, and they used MKTC there to produce virus cultures. Koprowski now denies that he used chimpanzee MKTC, although nothing in anything published at the time specified which particular MKTC was used. Koprowski claims that the chimpanzees were used to test the efficacy and virulence of the vaccine., and were not sacrificed to produce MKTC. However, there was nothing at the time which suggested which particular primates should be, or should not be, used to produce MKTC, indeed, the possibility of retroviral infection was unheard of at the time. It is likely at the time that any primate was considered as good as another for MKTC, and thus there was no reason not to use chimpanzees to supply MKTC.

Hooper’s evidence is meticulously researched and also demonstrates a high correlation to the application of the vaccine in geographic areas with early presentations of AIDS or AIDS-like cases. The use of MKTC as the agent that passed the SIV into a human also explains the anomaly of HIV-2.