West Nile Virus Epizootiology in the Southeastern United States, 2001

Abstract

We investigated mosquito and bird involvement in West Nile virus (WNV) transmission in July 2001 in Jefferson County, FL, and Lowndes County, GA. We detected 16 WNV-infected pools from Culex quinquefasciatus, Cx. salinarius, Cx. nigripalpus, and Culiseta melanura. In Florida, 11% of 353 bird sera neutralized WNV. Antibody prevalence was greatest in northern cardinal (Cardinalis cardinalis, 75%), northern mockingbird (Mimus polyglottus, 50%), common ground-dove (Columbina passerina, 25%), common grackle (Quiscalus quiscula, 15%), domestic chicken (Gallus gallus, 16%), and house sparrow (Passer domesticus, 11%). Antibody-positive birds were detected in nine of 11 locations, among which prevalence in chickens ranged from 0% to 100%. Seropositive chickens were detected in Georgia as well. The primary transmission cycle of WNV in the southeastern United States apparently involves Culex mosquitoes and passerine birds. Chickens are frequently infected and may serve as effective sentinels in this region.

Experimental Infection of Cliff Swallows (Petrochelidon pyrrhonota) with Varying Doses of West Nile Virus

“…5 House sparrows are competent WNV reservoir hosts 2 and are frequently exposed to WNV in various geographic regions. 1,[23][24][25] Experimentally inoculated sparrows reached viremia titers of up to ~10 10 PFU/mL serum, leading to a relatively high reservoir competence index for this species. [1][2][3] Therefore, the presence of house sparrows in cliff swallow colonies may lead to elevated WNV transmission levels, thereby increasing the likelihood of exposure to swallows.…”

Olfaction in vector-host interactions

“…nigripalpus Theobald, another mosquito species associated with West Nile virus transmission in the USA (Godsey et al 2005, Sardelis et al 2001, were attracted to tetradecanoic acid, dimethyl disulfide and methyl propyl disulfide and landed on casings treated with lactic acid, octadecanoic acid, dimethyl trisulfide, ethyl disulfide or methyl propyl disulfide, although responses to bovine blood were low (Allan et al 2006a). Culex nigripalpus and Cx.…”

Environmental and Biological Factors Influencing Culex pipiens quinquefasciatus (Diptera: Culicidae) Vector Competence for West Nile Virus

“…6 West Nile virus (WNV; family Flaviviridae : genus Flavivirus ) is maintained in an enzootic cycle involving ornithophilic mosquitoes and avian populations, and it threatens humans whenever large numbers of infectious mosquitoes exhibiting opportunistic feeding coincide with amplification hosts and human populations. 7 Culex p. quinquefasciatus feeds on both avian and mammalian hosts, [8][9][10] has been shown to be a competent vector of WNV in the laboratory, 3,11,12 has been found in nature to be infected with WNV, 13,14 and is considered a prominent WNV vector in the United States.…”