Figure 4.

a Hotspot map of the summed phylogenetic risk for host shifts across wild primates. Central Africa and west Amazonia represent regions of high geographical overlap among many closely related primate species. We predict host shifts among primates to be frequent in these localities. b Phylogenetic risk of pathogens host shifting to humans from wild primates. West central Africa is a hotspot of high risk to humans, due to the overlapping ranges of many of our closest relatives. c The intersection between high phylogenetic risk and an index of human population growth (increase in density from 1990–2000), revealing regions where we expect high rates of human contact with primate species that pose the greatest risk of cross-species pathogen transmission to humans. Open circles indicate human population centers (>25,000) that may facilitate disease emergence following host shift events.