Host Choice and West Nile Virus Infection Rates in Blood-Fed Mosquitoes, Including Members of theCulex pipiensComplex, from Memphis and Shelby County, Tennessee, 2002–2003

Abstract

The source of bloodmeals in 2,082 blood-fed mosquitoes collected from February 2002 through December 2003 in Memphis and surrounding areas of Shelby County, Tennessee were determined. Members of the genus Culex and Anopheles quadrimaculatus predominated in the collections. Members of the Cx. pipiens complex and Cx. restuans were found to feed predominately upon avian hosts, though mammalian hosts made up a substantial proportion of the bloodmeals in these species. No significant difference was seen in the host class of bloodmeals in mosquitoes identified as Cx. pipiens pipiens, Cx. p. quinquefasciatus, or hybrids between these two taxa. Anopheles quadrimaculatus and Cx. erraticus fed primarily upon mammalian hosts. Three avian species (the American Robin, the Common Grackle, and the Northern Cardinal) made up the majority of avianderived bloodmeals, with the American Robin representing the most frequently fed upon avian host. An analysis of these host feeding data using a modification of a transmission model for Eastern Equine encephalitis virus suggested that the American Robin and Common Grackle represented the most important reservoir hosts for West Nile virus. A temporal analysis of the feeding patterns of the dominant Culex species did not support a shift in feeding behavior away from robins to mammals late in the summer. However, a significant degree of temporal variation was noted in the proportion of robin-derived bloodmeals when the data were analyzed by semi-monthly periods throughout the summers of 2002 and 2003. This pattern was consistent with the hypothesis that the mosquitoes were preferentially feeding upon nesting birds.

Genetic-morphometric variation in Culex quinquefasciatus from Brazil and La Plata, Argentina

“…pipiens complex and to characterize populations and zones of hybridization (Bourguet et al 1998, Aspen & Savage 2003, Smith & Fonseca 2004, Savage et al 2007, Sanogo et al 2008, Kothera et al 2009). The fragment of the ace-2 locus was amplified from each DNA sample by PCR in a final reaction volume of 50 μL with 2 mM Mg ++ , 20 mM Tris-HCl (pH 8.4), 50 mM KCl, 0.5 mM of each primer, 0.2 mM dNTP mix, 2 U of Taq DNA polymerase (Invitrogen) and approximately 6.0 ng of genomic DNA.…”

Olfaction in vector-host interactions

“…In a study in Tucson, USA, blood meal analysis revealed that 50% of Cx. quinquefasciatus females fed on humans and 32% on birds, respectively (and therefore this species is considered to be a potential West Nile virus vector; Zinser et al 2004), whereas in Tenessee, USA, and Mexico they were found to feed less on humans than on birds (Eilizondo-Quiroga et al 2006, Savage et al 2007. In addition, a greater percentage of Cx.…”

Ecology of Potential West Nile Virus Vectors in Southeastern Louisiana: Enzootic Transmission in the Relative Absence of Culex quinquefasciatus

“…[31][32][33][34] In St. Tammany Parish during the 2002 outbreak, Cx. quinquefasciatus was the primary enzootic/epidemic vector, with Cx.…”

“…54 Culex erraticus feeds predominantly on mammals, but will also feed on birds. 32,49 Studies conducted in Tennessee showed that avian blood meal hosts of Cx. erraticus included American robins (Turdus migratorius), common grackles (Quiscalus quiscula), house finches (Carpodacus mexicanus), and Carolina wrens (Thryothorus ludovicianus).…”

“…erraticus included American robins (Turdus migratorius), common grackles (Quiscalus quiscula), house finches (Carpodacus mexicanus), and Carolina wrens (Thryothorus ludovicianus). 32,55 Robins, grackles, and house finches are effective amplifier hosts of WNV 9 and yearround or winter residents in southern Louisiana. 55 Serologic evidence of infection with WNV was obtained from Carolina wrens and common grackles captured in St. Tammany Parish in 2002.…”