Implications of predator species richness in terms of zoonotic spillover transmission of filovirus diseases in Africa

Background: Filovirus disease is a highly pathogenic zoonosis of humans caused by the viral genera Ebolavirus and Marburgvirus . A rich biodiversity of predators has been suggested to suppress the risk of zoonotic spillover by regulating prey abundance and behavior. However, the effects on bat-borne zoonoses remain to be investigated because the empirical findings are limited. Therefore, we evaluated the association between predator species richness and the spillover events of Ebolavirus and Marburgvirus in Africa. Methods: Historical records of filovirus outbreaks and ecological, geographical, and socioeconomic factors were considered in this environmental study. We utilized the maximum entropy approach (Maxent modeling) and stacked species distribution models to estimate predator species richness. Logistic regression analyses that considered spatiotemporal autocorrelations were conducted to assess the association between predator species richness and spillover risks after adjusting for potential confounding factors. Results: Higher species richness of certain predators (order Strigiformes and family Colubridae) were associated with lower risks of Ebolavirus spillover. In a model considering spatiotemporal autocorrelations, the third quartile (OR = 0.02, 95% CI 0.00–0.84) and fourth quartile (OR = 0.07, 95% CI 0.00–0.42) of Strigiformes species richness, the third quartile (OR = 0.15, 95% CI 0.01–0.73) and fourth quartile(OR = 0.53, 95% CI 0.03–0.85) of Colubridae species richness evidenced significantly lower risks of Ebolavirus index cases. We found no significant association between predator species richness and Marburgvirus spillover. Conclusions: The findings support a possible effect of predator species richness on spillover suppression. The concept of conservation epidemiology should be further developed to identify sustainable measures that maintain the environment and prevent zoonotic spillover.