The findings raise a host of new questions about the ability of immunodeficiency viruses to spread between species. Earlier this year, the same team of investigators traced the origins of the pandemic form of HIV-1 (termed group M) and a different non-pandemic form (group N) to distinct, geographically isolated chimpanzee communities in southern Cameroon. But the primate reservoir of the third lineage, HIV-1 group O, could not be identified.
By analysing fecal samples collected from the forest floor at remote jungle regions in Cameroon, the researchers were able to detect SIVgor antibodies and nucleic acids (viral genetic information) in three gorillas living nearly 400 km apart. To their surprise, evolutionary analyses revealed that the newly identified SIVgor viruses were the closest known relatives of HIV-1 group O.
Despite the finding of SIV infection in gorillas, the present study reaffirms that chimpanzees likely served as the primary reservoir of SIVs now found in chimpanzees, gorillas and humans.
Dr. Martine Peeters from the University of Montpellier, France said: “HIV-1 groups M and N clearly arose by transfer of viruses from chimpanzees to man, while the origin of HIV-1 group O is less clear. Chimpanzees could have transmitted group O-like viruses to gorillas and humans independently, or they could have transmitted the virus first to gorillas, which in turn transmitted it to humans.”
Dr. Beatrice Hahn from the University of Alabama at Birmingham, USA, said: “Either way, the finding of HIV-1 related viruses in wild gorillas opens a Pandora’s box of questions and speculation about the ability of these viruses to spread between species.”
MEDICA.de; Source: University of Nottingham