328 - A Cornucopia of Blood: Host Preference of Culex nigripalpus in Collier County

Abstract: Culex nigripalpus is an important vector of West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) in Florida. In order to transmit these zoonotic viruses to human incidental hosts, Cx. nigripalpus must first feed on viruliferous birds. Until recently, it had been assumed that Culex mosquitoes preferentially feed on birds and mammals. However, a recent study found that between 10-60% of Culex mosquito bloodmeals in Florida come from lizards, with the relative percentage increasing the further south the Culex mosquitoes were collected. Although it is not yet known whether Florida lizards serve as reservoirs or dead-end hosts for WNV and SLEV, it is likely that they play a significant role in local epidemiological cycles, particularly in south Florida. Southwest Florida’s Collier County has exceptional environmental diversity, which facilitates interactions between a wide variety of different mosquito and host species.



The objective of this study was to determine which hosts Cx. nigripalpus feeds on in Collier County, and how host preference may shift across seasons, years, and localities. Bloodfed Cx. nigripalpus were collected from trap locations across the county. Bloodmeals were preserved on FTA cards, and the hosts were identified based on molecular barcoding of the COI gene. Preliminary results suggest that Cx. nigripalpus is an extremely opportunistic mosquito; of the 78 bloodmeal samples processed so far, 20 different host species were identified, approximately 15% of which were invasive lizards. Within the county, the results of this study will help inform operational treatment choices during periods when vector populations are high. More broadly, it will add to the growing body of literature regarding Culex host choice dynamics, allowing researchers to further refine localized predictions of zoonotic virus outbreaks.