HIV May Have Been Infecting Humans For A Century

A biopsy taken from an African woman nearly 50 years ago contains traces of the HIV genome, researchers have found. Analysis of sequences from the newly discovered sample suggests that the virus has been plaguing humans for almost a century.

However, it may never be possible to pinpoint exactly how HIV crossed from chimpanzees into humans, Hahn cautions. She and her collaborators previously tracked the likely source of HIV-1 to chimpanzees living in southeast Cameroon4, hundreds of kilometres from Kinshasa, and it is tempting to hypothesize that trade routes contributed to the virus's infiltration of the city. But even by 1960, HIV-1 had infected only a few thousand Africans. It is unlikely that it will be possible to track down samples from the very earliest victims, Hahn notes.

Meanwhile, Worobey plans to continue his search through old tissue collections in the hope of finding additional samples. In time, he says, it may even be possible to reconstruct the historic HIV viruses for further study.

Collecting information about old strains of HIV — even those that disappeared over time — can help researchers learn how successful strains broke through, says Wain-Hobson. "For every star in Hollywood there are fifty starlets," he says. "We would love to know what it was that caused this strain to move out of starlet phase and to the big time."