Deforestation alters spillover risk of multi-host pathogens

Annalise Cramer, a student at Westfield State University, worked in the lab of Dr. Richard Hall

Abstract Deforestation alters landscape configuration resulting in novel contacts between host species, which can promote pathogen spillover from wildlife to domesticated animals and humans. Given heightened awareness of zoonotic spillover, studies are urgently needed to understand how the rate of deforestation interacts with host abundance and distribution to shape pathogen transmission across habitats and human exposure risk. In this study, we derive a mathematical model coupling land use change with pathogen transmission between hosts in forested and deforested habitats. We explore how deforestation rate and host relative abundance across habitats influence the dynamics, peak and cumulative number of infected hosts in deforested habitats as a proxy for human spillover risk. We find that the number of infected hosts in deforested habitats peaks sooner under faster deforestation rates. When the deforested hosts are less abundant, most transmission occurs in mixtures of forested and deforested habitats where large habitat boundaries maximize contacts with the more abundant forest hosts. This results in a hump-shaped relationship between deforestation rate and short- and long-term spillover risk. These results suggest that surveillance and interventions at habitat boundaries are crucial to reduce the risk of zoonotic spillover.