Systematic review of zoonotic pathogens of wild Asian primates in different habitat types

Ongoing global changes, such as deforestation and the expansion of urban and agricultural areas, are causing deep modifications of the landscape and of the human-primate contact dynamics associated with a potential zoonotic risk. Although Asia has a high primate diversity and is characterized by a rapid multiplication of human-primate contact zones, this region remains little studied in terms of zoonotic surveillance in primates. We carried out a systematic review using the PRISMA guidelines in order to make an inventory of the zoonotic pathogens identified in wild Asian primates. Moreover, we compared the specific richness of pathogens and their transmission routes between different habitat types classified according to their degree anthropization (i.e., urban vs rural vs forest habitat). A total of 65 articles were selected on 25 primate species, using Scopus, PubMed and the Global Mammal Parasite Database. We inventoried 131 pathogens including 53 helminthic gastrointestinal parasites, 34 protozoa, 29 viruses, 14 bacteria and 1 fungi. The accumulation curves showed no significant difference in specific richness of gastrointestinal parasite and protozoa between habitat types. However, the sampling effort was probably to low to be conclusive. Regarding the transmission routes, we observed that most viruses identified in urban areas were transmitted by body fluid contact or aerosol, while viruses detected in rural and forest habitats were mainly transmitted by vectors. This review allowed us to identify several gaps in the literature constituting potential biases for the inventory. In particular, the Macaca genus was over-represented in comparison with other species, and studies screened further for protozoa and gastrointestinal parasites than for viruses, bacteria or fungi. . These gaps in research on zoonotic pathogens in Asian primates emphasize the critical need for further exhaustive studies implemented through a multidisciplinary approach in order to understand and limit the zoonotic transmission risk at the human-primate interfaces.