Vector competence of Culex restuans (Diptera: Culicidae) from two regions of Chicago with low and high prevalence of West Nile virus human infections.

Vector competence studies for West Nile virus (WNV) were conducted for two Culex (Culex) restuans Theobald populations Edison Park (EP) and Illinois Medical District (IMD), in Chicago, IL. The aim was to determine if there were differences between mosquito populations that contributed to the observed differences in the prevalence of WNV. Percentages of orally infected, disseminated, and transmitting mosquitoes were estimated using a generalized linear mixed effects model including a random effect for family to account for anticipated within-family correlation. Analysis indicated that percentages of infected, disseminated, and transmitting mosquitoes were not significantly different between EP and IMD. The within-family correlation was 0.46 (95% CI 0.28, 0.67), indicating reasonably strong tendency for WNV titers of bodies, saliva, and legs within families to be similar. Overall, our results show that vector competence of Cx. restuans for WNV is not a contributing factor to the observed differences in WNV human cases between the EP and IMD areas of Chicago.