Infection and host-feeding patterns of West Nile virus vectors varies by urban greenspace composition

Greenspaces are integral to the urban environment, enhancing climate resilience and providing several additional environmental, social, and public health benefits, yet the extent to which they affect vector-borne disease transmission is not clear. We explored this question in the context of mosquito and West Nile virus (WNV) host populations, infection rates, and foraging behavior. We collected mosquitoes from greenspaces along a transect spanning a range of urban development. Mosquitoes were tested for West Nile virus, and the host species that were fed on was determined for blood-fed specimens. Bird counts and camera traps were used to assess avian and mammal species availability. We explored landcover associations with vector abundance, vector infection prevalence, host-feeding pattern,s and host community composition.

Different components that contribute to WNV transmission intensity responded to different landcover variables. Abundance of Culex mosquitoes was most strongly tied to impervious surface, while prevalence of WNV infection was positively associated with increasing amounts of turf grass, but not through an indirect effect of vapor pressure deficit. The amount of turf was itself correlated with a measure of avian community reservoir competence. Blood meal analysis suggested the majority of blood meals in Cx. pipiens and Cx. restuans came from American robins and northern cardinals. This work provides novel insights into how reliance on managed turf grass for urban landscaping may have adverse consequences for WNV transmission risk and furthers our understanding of how the design of urban greenspaces could benefit from consideration of vector-host-virus interactions.