RESUMO
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.
Assuntos
Anticorpos Antivirais/sangue , Doenças das Aves/epidemiologia , Galinhas , Culicidae/virologia , Insetos Vetores/virologia , Febre do Nilo Ocidental/veterinária , Animais , Doenças das Aves/transmissão , Aves , Vetores de Doenças , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/transmissão , Vigilância de Evento Sentinela , Estudos Soroepidemiológicos , Sudeste dos Estados Unidos/epidemiologia , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/transmissão , Vírus do Nilo OcidentalRESUMO
After West Nile virus (WNV) was first detected in Florida in July 2001, intensive surveillance efforts over the following five months uncovered virus activity in 65 of the state's 67 counties with 1,106 wild birds, 492 horses, 194 sentinel chickens, and 12 people found infected with the virus. Thirteen of 28 mosquito isolations came from Culex mosquitoes. As seen in the northeastern United States, wild bird mortality was the most sensitive surveillance method. However, unlike the predominantly urban 1999 and 2000 epizootics, the Florida transmission foci were rural with most activity detected in the northern part of the state. All human cases were preceded by the detection of WNV in animals; however, only eight of the twelve cases were preceded by reports of WNV activity in the county of residence. West Nile virus-positive animals detected by multiple surveillance systems preceded seven of these cases by two weeks or more.
