Two of the four known groups of human AIDS originated in western lowland gorillas, according to an international team of scientists.
The researchers conducted a comprehensive survey of simian immunodeficiency virus (SIV) infection in African gorillas.
HIV-1, the virus which causes AIDS, has jumped species to infect humans on at least four separate occasions, generating four HIV-1 lineages — groups M, N, O, and P.
Previous research from this team found that groups M and N originated in geographically distinct chimpanzee communities in southern Cameroon, but the origins of groups O and P remained uncertain.
The four cross-species transmissions have had very different outcomes in humans. Group M gave rise to the AIDS pandemic, infecting more than 40 million people worldwide by spreading across Africa and throughout the rest of the world.
Groups N and P have only been found in a few individuals from Cameroon. However, group O, although not as widespread and prevalent as group M, has nonetheless infected about 100,000 people in west central Africa.
“Understanding emerging disease origins is critical to gauge future human infection risks,” says Martine Peeters from the University of Montpellier. “From this study and others that our team has conducted in the past it has become clear that both chimpanzees and gorillas harbour viruses that are capable of crossing the species barrier to humans and have the potential to cause major disease outbreaks.”
The results of the study by researchers at the Perelman School of Medicine at the University of Pennsylvania, the University of Montpellier, the University of Edinburgh, is published in the journal PNAS (Proceedings of the National Academy of Sciences).
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