title: Five-year surveillance of West Nile and eastern equine encephalitis viruses in Southeastern Virginia.
abstract: To investigate the occurrence of West Nile virus (WNV) and Eastern equine encephalitis virus (EEE) in southeastern Virginia, the Bureau of Laboratories at the Norfolk Department of Public Health (NDPH) analyzed mosquito pools and the sera of sentinel chickens from the southeastern Virginia area each year from 2000 to 2004. Mosquito pool supernatants were screened for the presence of viral RNA by conventional reverse transcription polymerase chain reaction (RT-PCR) and Taqman RT-PCR with the i-Cycler. Mosquito pools were also tested for virus activity by Vero cell culture. The primary enzootic vector of WNV was Culex (Cx.) pipiens and that of EEE was Culiseta (Cs.) melanura. During the five-year surveillance period, the peak minimum infection rates (MIRs) of WNV and EEE in these mosquito species were 2.7 (2002) and 0.9 (2001), respectively. In 2003, the MIRs in Cs. melanura for WNV and EEE were 0.24 and 0.56, respectively; and the MIR for WNV in Cx. pipiens was 0.64. In 2004, Cs. melanura was less active in the WNV transmission cycle (MIR = 0.07) than was Cx. pipiens (MIR = 1.8), and Cs. melanura was the only vector for EEE (MIR = 0.37). The trend was for EEE activity to peak in July; WNV activity peaked in August. Sentinel-chicken sera were tested for IgM antibodies, and peak IgM seroconversions to these arboviruses were recorded in August 2003 for WNV and in July 2003 for EEE. In 2004, the highest IgM seroconversions to EEE occurred later in August. The overall trend of arbovirus activity was greater in 2003 than in 2004.
authors.affiliation: Norfolk Public Health Laboratory, Commonwealth of Virginia, Norfolk, VA 23510, USA.
authors.forename: Karin C
authors.initials: KC
authors.lastname: Loftin
authors.forename: Alpha A
authors.initials: AA
authors.lastname: Diallo
authors.forename: Marcia W
authors.initials: MW
authors.lastname: Herbert
authors.forename: Priyarshadan G
authors.initials: PG
authors.lastname: Phaltankar
authors.forename: Christine
authors.initials: C
authors.lastname: Yuan
authors.forename: Norman
authors.initials: N
authors.lastname: Grefe
authors.forename: Agnes
authors.initials: A
authors.lastname: Flemming
authors.forename: Kirby
authors.initials: K
authors.lastname: Foley
authors.forename: Jason
authors.initials: J
authors.lastname: Williams
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Fisher
authors.forename: Michael
authors.initials: M
authors.lastname: Elberfeld
authors.forename: Juan
authors.initials: J
authors.lastname: Constantine
authors.forename: Mitchell
authors.initials: M
authors.lastname: Burcham
authors.forename: Valerie
authors.initials: V
authors.lastname: Stallings
authors.forename: Dongxiang
authors.initials: D
authors.lastname: Xia
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000821:virology; D002645:Chickens / Q000821:virology*; D002522:Chlorocebus aethiops; D009033:Culicidae / Q000145:classification / Q000821:virology*; D004663:Encephalitis Virus, Eastern Equine / Q000235:genetics / Q000302:isolation & purification*; D020242:Encephalomyelitis, Eastern Equine / Q000453:epidemiology / Q000662:veterinary / Q000821:virology; D007303:Insect Vectors / Q000145:classification / Q000821:virology; D012367:RNA, Viral / Q000032:analysis; D011891:Rain; D018571:Sentinel Surveillance; D013696:Temperature; D014709:Vero Cells; D014768:Virginia / Q000453:epidemiology; D014901:West Nile Fever / Q000453:epidemiology / Q000662:veterinary / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D012367:RNA, Viral