Molecular epidemiology of simian immunodeficiency virus infection in wild-living gorillas.
Cécile Neel, Lucie Etienne, Yingying Li, Jun Takehisa, Rebecca S Rudicell, Innocent Ndong Bass, Joseph Moudindo, Aimé Mebenga, Amandine Esteban, Fran Van Heuverswyn, Florian Liegeois, Philip J Kranzusch, Peter D Walsh, Crickette M Sanz, David B Morgan, Jean-Bosco N Ndjango, Jean-Christophe Plantier, Sabrina Locatelli, Mary K Gonder, Fabian H Leendertz, Christophe Boesch, Angelique Todd, Eric Delaporte, Eitel Mpoudi-Ngole, Beatrice H Hahn, Martine Peeters
Author Information
Cécile Neel: UMR 145, Institute of Research and Development and University of Montpellier 1, 911 Avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France.
Chimpanzees and gorillas are the only nonhuman primates known to harbor viruses closely related to HIV-1. Phylogenetic analyses showed that gorillas acquired the simian immunodeficiency virus SIVgor from chimpanzees, and viruses from the SIVcpz/SIVgor lineage have been transmitted to humans on at least four occasions, leading to HIV-1 groups M, N, O, and P. To determine the geographic distribution, prevalence, and species association of SIVgor, we conducted a comprehensive molecular epidemiological survey of wild gorillas in Central Africa. Gorilla fecal samples were collected in the range of western lowland gorillas (n = 2,367) and eastern Grauer gorillas (n = 183) and tested for SIVgor antibodies and nucleic acids. SIVgor antibody-positive samples were identified at 2 sites in Cameroon, with no evidence of infection at 19 other sites, including 3 in the range of the Eastern gorillas. In Cameroon, based on DNA and microsatellite analyses of a subset of samples, we estimated the prevalence of SIVgor to be 1.6% (range, 0% to 4.6%), which is significantly lower than the prevalence of SIVcpzPtt in chimpanzees (5.9%; range, 0% to 32%). All newly identified SIVgor strains formed a monophyletic lineage within the SIVcpz radiation, closely related to HIV-1 groups O and P, and clustered according to their field site of origin. At one site, there was evidence for intergroup transmission and a high intragroup prevalence. These isolated hot spots of SIVgor-infected gorilla communities could serve as a source for human infection. The overall low prevalence and sporadic distribution of SIVgor could suggest a decline of SIVgor in wild populations, but it cannot be excluded that SIVgor is still more prevalent in other parts of the geographical range of gorillas.
