Neotropical Primates and Humans: Risk of Bidirectional Parasite Transmission and Disease Sharing in Fragmented and Pristine Landscapes

A close phylogenetic relationship between nonhuman primates (NHPs) and humans is recognized as a causal subjacent factor to the sharing and coevolution of zoonotic pathogens. A relevant barrier to limit the transmission of infectious agents between humans and NHPs is the reduction of exposure and interspecific encounters. Neotropical NHPs occur from southern Mexico through northern Argentina and southern Brazil, presenting high species diversity. All Neotropical NHPs live in forests and are eminently arboreal, although they can descend to the forest floor to cross canopy gaps, to move or disperse between forest fragments, to access food patches located in the anthropogenic matrix, or to drink water from ground sources. A significant proportion of NHP populations have been encroached by human activities, a scenario that has favored contact with humans. The spillover of infectious agents is also possible whenever humans come into close contact with NHPs. This bidirectional pathogen exchange is only successful when the infectious agent adapts to the new host and reaches a high propagation density. In this review, we assess the risk of bidirectional transmission between humans and Neotropical NHPs facilitated by anthropogenic, ecological, and biological variables that may favor their spread in a fragmented Neotropical landscape.