title: Detection of West Nile virus-infected mosquitoes and seropositive juvenile birds in the vicinity of virus-positive dead birds.
abstract: Mosquitoes and wild birds were collected from three sites near locations in the New York City metropolitan area where single, West Nile (WN) virus-positive dead birds were found early in the 2000 transmission season. The mosquitoes were tested for the presence of infectious virus with a Vero cell culture assay and for WN viral RNA by using reverse transcriptase-polymerase chain reaction (RT-PCR) protocols. Serum samples from wild birds were tested for the presence of neutralizing antibodies against WN virus. Infectious WN virus and WN viral RNA were found in Culex species adult mosquitoes from each of the three sites, and a seropositive hatch-year house sparrow (Passer domesticus) was found in one of the three sites. Molecular techniques used to identify the species in the positive mosquito pools found that most of the pools contained a combination of Culex pipiens and Cx. restuans. The minimum infection rate in Culex species mosquitoes from the sites ranged from 0.2 to 6.0 per 1,000 specimens tested. The results demonstrated that, at least early in the transmission season, detection of a WN virus-positive dead bird indicates a local WN virus transmission cycle. This information is valuable in focusing subsequent surveillance and vector management programs. In addition, the RT-PCR procedure for detecting WN viral RNA in mosquito pools detected more positive pools than did the Vero cell plaque assay.
authors.affiliation: Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 80522, USA. rsn0@cdc.gov
authors.forename: Roger S
authors.initials: RS
authors.lastname: Nasci
authors.forename: Nicholas
authors.initials: N
authors.lastname: Komar
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Marfin
authors.forename: George V
authors.initials: GV
authors.lastname: Ludwig
authors.forename: Laura D
authors.initials: LD
authors.lastname: Kramer
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Daniels
authors.forename: Richard C
authors.initials: RC
authors.lastname: Falco
authors.forename: Scott R
authors.initials: SR
authors.lastname: Campbell
authors.forename: Kelsey
authors.initials: K
authors.lastname: Brookes
authors.forename: Kristy L
authors.initials: KL
authors.lastname: Gottfried
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Burkhalter
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Aspen
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Kerst
authors.forename: Robert S
authors.initials: RS
authors.lastname: Lanciotti
authors.forename: Chester G
authors.initials: CG
authors.lastname: Moore
mesh_terms: D000375:Aging; D000818:Animals; D000914:Antibodies, Viral / Q000302:isolation & purification; D001715:Bird Diseases / Q000453:epidemiology / Q000401:mortality* / Q000821:virology*; D003465:Culex / Q000821:virology*; D004197:Disease Reservoirs; D005260:Female; D007303:Insect Vectors / Q000821:virology; D008297:Male; D009518:New York / Q000453:epidemiology; D012367:RNA, Viral / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020308:Songbirds / Q000097:blood / Q000145:classification / Q000821:virology*; D014902:West Nile virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral