Simian Immunodeficiency Virus Infection in Free-Ranging Sooty Mangabeys ( Cercocebus atys atys ) from the Taï Forest, Côte d'Ivoire: Implications for the Origin of Epidemic Human Immunodeficiency Virus Type 2

Abstract

Simian immunodeficiency virus of sooty mangabeys (SIVsmm) is recognized as the progenitor of human immunodeficiency virus type 2 (HIV-2) and has been transmitted to humans on multiple occasions, yet the epidemiology and genetic diversity of SIVsmm infection in wild-living populations remain largely unknown.Here, we report the first molecular epidemiological survey of SIVsmm in a community of ϳ120 free-ranging sooty mangabeys in the Taï Forest, Côte d'Ivoire. Fecal samples (n ‫؍‬ 39) were collected from 35 habituated animals (27 females and 8 males) and tested for SIVsmm virion RNA (vRNA). Viral gag (800 bp) and/or env (490 bp) sequences were amplified from 11 different individuals (eight females and three males). Based on the sensitivity of fecal vRNA detection and the numbers of samples analyzed, the prevalence of SIVsmm infection was estimated to be 59% (95% confidence interval, 0.35 to 0.88). Behavioral data collected from this community indicated that SIVsmm infection occurred preferentially in high-ranking females. Phylogenetic analysis of gag and env sequences revealed an extraordinary degree of genetic diversity, including evidence for frequent recombination events in both the recent and distant past. Some sooty mangabeys harbored near-identical viruses (<2% interstrain distance), indicating epidemiologically linked infections. These transmissions were identified by microsatellite analyses to involve both related (mother/daughter) and unrelated individuals, thus providing evidence for vertical and horizontal transmission in the wild. Finally, evolutionary tree analyses revealed significant clustering of the Taï SIVsmm strains with five of the eight recognized groups of HIV-2, including the epidemic groups A and B, thus pointing to a likely geographic origin of these human infections in the eastern part of the sooty mangabey range.

Origin and Biology of Simian Immunodeficiency Virus in Wild-Living Western Gorillas

“…Until recently, SIV cross-species transmissions could be detected only by analyzing blood samples coincident with the capture or killing of primates (10,32,73). However, the development of noninvasive viral detection methods has transformed the way infectious agents, including SIV, can be studied in wild-living primate populations (33,38,(51)(52)(53)(54)70). For example, systematic testing of fecal samples from wild-living chimpanzees (Pan troglodytes) for viral nucleic acids and antibodies traced the origin of pandemic (group M) and nonpandemic (group N) human immunodeficiency virus type 1 (HIV-1) to distinct chimpanzee communities in south-central and southeastern Cameroon, respectively (33).…”

Phylogénie des SIV et des VIH

“…Les SIV les plus proches du VIH-1 sont le SIVcpz et SIVgor qui infectent naturellement les chimpanzés (Pan troglodytes troglodytes) et les gorilles (Gorilla gorilla) d'Afrique Centrale de l'ouest. Les SIVsmm retrouvés chez les mangabeys enfumés (Cercocebus atys) d'Afrique de l'Ouest sont les plus proches pour le VIH-2 [1][2][3]. [4][5][6] (Figure 1).…”

Simian-Human Immunodeficiency Viruses and Their Impact on Non-Human Primate Models for AIDS

“…Epidemiological and phylogenetic analyses have established that the origin of the HIV-1 and HIV-2 strains is the result of cross-species transmission of the NHP lentivirus equivalents SIVcpz and SIVsm from Eastern/Central African chimpanzees and the West African sooty mangabey, respectively [1][2][3][4][5][6][7][8]. More recently, there was also evidence demonstrating cross-species transmission of a distinct SIV lineage from gorillas [9].…”