Mother-offspring transmission and age-dependent accumulation of simian foamy virus in wild chimpanzees

Simian foamy viruses (SFVs) are thought to infect virtually any adult non-human primate (NHP). While much data have accumulated about patterns of co-divergence with their hosts and cross-species transmission events, little is known about the modalities of SFV transmission within NHP species, especially in the wild. Here we provide a detailed investigation of the dynamics of SFV circulation in a wild community of Western chimpanzees (Pan troglodytes verus). We demonstrate that mother–offspring (vertical) SFV transmission is common and hypothesize that it accounts for a number of primary infections. We also show that multiple infections with several chimpanzee specific SFV strains (i.e., super-infection) commonly happen in adult chimpanzees, which might point at adult-specific aggressive behaviors as a lifelong source of SFV infection. Our data give evidence for complex SFV dynamics in wild chimpanzees, even at a single community scale, and show that linking wild NHP social interactions and their microorganisms’ dynamics is feasible.