  Infectious zoonotic disease emergence, through spillover events, is of global
concern and has the potential to cause significant harm to society, as recently
demonstrated by COVID-19. More than 70% of the 400 infectious diseases that
emerged in the past five decades have a zoonotic origin, including all recent
pandemics. There have been several approaches used to predict the risk of
spillover through some of the known or suspected infectious disease emergence
drivers, largely using correlative approaches. Here, we predict the spatial
distribution of spillover risk by approximating general transmission through
animal and human interactions. These mass action interactions are approximated
through the multiplication of the spatial distribution of zoonotic viral
diversity and human population density. Although our results indicate higher
risk in regions along the equator and in Southeast Asia where both viral
diversity and human population density are high, it should be noted that this
is primarily a conceptual exercise. We compared our spillover risk map to key
factors, including the model inputs of zoonotic viral diversity estimate map,
human population density map, and the spatial distribution of species richness.
Despite the limitations of this approach, this viral spillover map is a step
towards developing a more comprehensive spillover risk prediction system to
inform global monitoring.
