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SOUTH-eastern Cameroon has emerged as the likely source of the pandemic form of HIV.

Using a technique she and her team developed, Beatrice Hahn from the University of Alabama at Birmingham showed that antibodies to one strain of the chimpanzee form of HIV, called SIVcpz, are present in faecal samples from the subspecies Pan troglodytes troglodytes in south-eastern Cameroon (Science, DOI: 10.1126/science.1126531).

This is likely to be the location of the original crossover from chimps to humans. The SIVcpz strain is much closer to HIV-1 group M, the pandemic form that infects humans, than any SIV strain found before or likely to be found, says co-author Paul Sharp of the University of Nottingham, UK. From Cameroon the virus spread south to Kinshasa, the capital of the Democratic Republic of the Congo, where the pandemic began.