A Link between SIVsm in Sooty Mangabeys (SM) in Wild-Living Monkeys in Sierra Leone and SIVsm in an American-Based SM Colony

We have developed a noninvasive method for SIVsm virion RNA detection in feces of captive sooty mangabeys (SMs) (Cercocebus atys). Employing this method to investigate the natural history of SIVsm in endangered SMs is useful for understanding the diversity and evolution of SIVsm and HIV-2. The fecal samples of 61 wild-living SMs and 14 chimpanzees (Pan troglodytes verus) were studied. Samples were collected in rural Sierra Leone in 1993. One SM sample tested positive by reverse transcriptase-PCR. No viral sequence was detected in the feces of 14 chimpanzees. Phylogenetic analysis of the env sequence obtained from SM#13 showed that it clustered within the SIVsm lineage that includes SIVsmH4, B670, and PBj, confirming a direct connection between SIVsm from West Africa and an American-based colony of SM. The virus, designated as SIVsmSL93g, supports a link between the SIVB670/SIVsmH4/SIVPbj lineage and SMs living in Northern Sierra Leone in 1993. The discovery of this strain in a wild-living SM also indicates that noninvasive methods can be used for SIV detection from monkey feces collected in the field.