The Relationship between Vector Species Richness and the Risk of Vector-Borne Infectious Diseases

Infectious diseases can impact human welfare and impede wildlife management. Much recent research explores whether biodiversity increases or decreases infectious disease risk. Here, we theoretically study the relationship between vector species richness and the risk of vector-borne diseases using an epidemiological model of a single host and multiple vectors. The model considers that vectors are involved in interspecific feeding interference that causes transmission interference and in interspecific recruitment competition that mediates susceptible vector regulation. The model reveals three possible shapes of the vector richness-disease risk relationship: monotonic amplification, hump-shaped, and monotonic dilution patterns. The monotonic amplification pattern occurs across a wide parameter region. The hump-shaped and monotonic dilution patterns are found when transmission interference is strong and recruitment competition is weak. Unexpectedly, susceptible vector regulation not only promotes dilution but can strengthen amplification if coupled with strong transmission interference. Our results suggest that vector richness might be more likely to cause amplification rather than dilution, and shifts in the community mean trait values of vectors could also affect disease risk along the vector richness gradient.

Automated summary

Infectious diseases have significant impacts on human welfare and wildlife management. Research has examined the relationship between biodiversity and infectious disease risk, particularly in relation to vector species richness. This study utilizes an epidemiological model to explore the relationship between vector species richness and vector-borne disease risk. The model considers the role of interspecific feeding interference and recruitment competition in transmission dynamics. Results indicate three potential patterns: monotonic amplification, hump-shaped, and monotonic dilution. The findings suggest that vector richness is more likely to amplify disease risk rather than reduce it.