Yellow fever surveillance suggests zoonotic and anthroponotic emergent potential

Yellow fever is transmitted by mosquitoes among human and non-human primates. In the last decades, infections are occurring in areas that had been free from yellow fever for decades, probably as a consequence of the rapid spread of mosquito vectors, and of the virus evolutionary dynamic in which non-human primates are involved. This research is a pathogeographic assessment of where enzootic cycles, based on primate assemblages, could be amplifying the risk of yellow fever infections, in the context of spatial changes shown by the disease since the late 20(th) century. In South America, the most relevant spread of disease cases affects parts of the Amazon basin and a wide area of southern Brazil, where forest fragmentation could be activating enzootic cycles next to urban areas. In Africa, yellow fever transmission is apparently spreading from the west of the continent, and primates could be contributing to this in savannas around rainforests. Our results are useful for identifying new areas that should be prioritised for vaccination, and suggest the need of deep yellow fever surveillance in primates of South America and Africa. Models based on primates and disease vectors indicate a risk of zoonotic and anthroponotic yellow fever expansion in South America and Africa.

Automated summary

Yellow fever is a disease transmitted by mosquitoes, and in recent years, infections have occurred in areas where it was previously absent, possibly due to the rapid spread of mosquito vectors and the evolutionary dynamics of the virus in non-human primates. The study identifies the Amazon basin and southern Brazil in South America, as well as the western region of Africa, as areas with significant yellow fever transmission. It highlights the importance of monitoring yellow fever infections in primates in these regions.