Origine, diffusion et évolution des VIH-1 de groupe O.

HIV-1 group O (HIV-1/O) are rare variants that are mainly found in Cameroon, where they represent several thousands of cases. The reasons for their limited diffusion remains poorly understood: their emergence is estimated as ancient as that of pandemic HIV-1/M, and ancient cases of exportation on diverse continents have been identified for both groups. In France, more than a hundred cases have been identified so far that are mostly linked with Cameroon. HIV-1/O have developed a great level of genetic diversity and an atypical phylogenetic structure whose description remained ambiguous, due to the existence of several nomenclatures, which have only recently been unified. Their great genetic diversity and divergence from HIV-1/M probably impacts diverse properties, such as counteraction of Tetherin. Further studying the epidemiologic, evolutionary and virologic characteristics of these variants will allow for a better understanding of their limited spread and the future of this epidemic. In this respect, the recent description of diverse M/O intergroup recombinant forms underlines an evolutionary potential.