The Puzzling Origins of AIDS

Four rival theories provide some interesting lessons

Jim Moore

How did HIV originate? Four ideas are under serious consideration. One is quite controversial—the notion that the progenitor virus (which in the case of HIV-1 is found in chimpanzees) crossed into humans through a large-scale trial of an experimental oral polio vaccine carried out in the Belgian Congo between 1957 and 1960. The main competing theory is that the simian progenitor virus passed to humans through cuts as someone was hunting or butchering a chimpanzee (or, in the case of HIV-2, a type of West African monkey called the sooty mangabey). The difficulty with the cut-hunter concept is that, taken alone, it does not explain why the simian progenitor virus did not make the jump to humans before the middle of the 20th century (and then, why it did so multiple times). To answer that riddle, two modifications have been proposed. Both suggest that accidental blood-to-blood contact accounts for how these simian viruses first infected people and that specific human actions allowed them to spread in the population and eventually mutate to HIV, sparking the current pandemic. One hypothesis implicates the widespread reuse of disposable syringes, which were introduced during the 1950s. The other focuses on the disruptions of the colonial era, a time when Europeans brutalized the natives of Central Africa, resulting in the deaths of millions and forcing large-scale population shifts—all the while subjecting many Africans to medical treatments that probably involved the reuse of unsterilized syringes. Moore, an anthropologist and an author of the last of these theories, gives a balanced account of the various possibilities.

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