Origin of the HIV-1 group O epidemic in western lowland gorillas

Mirela D'Arc, Ahidjo Ayouba, Amandine Esteban, Gerald H. Learn, Vanina Boué, Florian Liegeois, Lucie Etienne, Nikki Tagg, Fabian H. Leendertz, Christophe Boesch, Nadège F. Madinda, Martha M. Robbins, Maryke Gray, Amandine Cournil, Marcel Ooms, Michael Letko, Viviana A. Simon, Paul M. Sharp, Beatrice H. Hahn*, Eric DelaporteEitel Mpoudi Ngole, Martine Peeters

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


HIV-1, the cause of AIDS, is composed of four phylogenetic lineages, groups M, N, O, and P, each of which resulted from an independent cross-species transmission event of simian immunodeficiency viruses (SIVs) infecting African apes. Although groups M and N have been traced to geographically distinct chimpanzee communities in southern Cameroon, the reservoirs of groups O and P remain unknown. Here,we screened fecal samples from western lowland (n = 2,611), eastern lowland (n = 103), and mountain (n = 218) gorillas for gorilla SIV (SIVgor) antibodies and nucleic acids. Despite testing wild troops throughout southern Cameroon (n = 14), northern Gabon (n = 16), the Democratic Republic of Congo (n = 2), and Uganda (n = 1), SIVgor was identified at only four sites in southern Cameroon, with prevalences ranging from 0.8-22%. Amplification of partial and full-length SIVgor sequences revealed extensive genetic diversity, but all SIVgor strains were derived from a single lineage within the chimpanzee SIV (SIVcpz) radiation. Two fully sequenced gorilla viruses from southwestern Cameroon were very closely related to, and likely represent the source population of, HIV-1 group P. Most of the genome of a third SIVgor strain, from central Cameroon, was very closely related to HIV-1 group O, again pointing to gorillas as the immediate source. Functional analyses identified the cytidine deaminase APOBEC3G as a barrier for chimpanzee-to-gorilla, but not gorilla-to-human, virus transmission. These data indicate that HIV-1 group O, which spreads epidemically in west central Africa and is estimated to have infected around 100,000 people, originated by cross-species transmission from western lowland gorillas.

Original languageEnglish
Pages (from-to)E1343-E1352
JournalProceedings of the National Academy of Sciences
Issue number11
Publication statusPublished - 17 Mar 2015


  • AIDS
  • Gorilla
  • HIV-1
  • SIVgor
  • Zoonotic transmission


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