Neel C, Etienne L, Li Y, Takehisa J, Rudicell RS, Ndong I, Moudindo J, Mebenga A, Esteban A, Van Heuverswyn F, Liegeois F, Kranzusch PJ, Walsh PD, Sanz CM, Morgan DB, Ndjango JB, Plantier JC, Locatelli S, Gonder MK, Leendertz FH et al. (2010): Molecular Epidemiology of Simian Immunodeficiency Virus Infection in Wild-living Gorillas
J. Virol. 84 (3): 1464-1476. Epub 2009 Nov 11.

Chimpanzees and gorillas are the only non-human primates known to harbor viruses closely related to HIV-1. Phylogenetic analyses showed that gorillas acquired SIVgor from chimpanzees and viruses from the SIVcpz/SIVgor lineage have been transmitted to humans on at least 4 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 faecal samples were collected in the home range of western lowland gorillas (n=2367) and eastern Grauer gorillas (n=183), and tested for SIVgor specific antibodies and nucleic acids. SIVgor antibody positive samples were identified at two sites in Cameroon, with no evidence of infection at 19 other sites, including three 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 group O and P, and clustered according to their field site of origin. At one site, there was evidence for intergroup transmission and high intra-group 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 home range of gorillas.