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.
Publication Date: 2006-05-16 PubMed ID: 16696451
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- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
- Animal Science
- Arboviruses
- Disease control
- Disease Outbreaks
- Disease Prevalence
- Disease Surveillance
- Eastern Equine Encephalitis
- Epidemiology
- Equine Diseases
- Horses
- Immunoglobulin M
- Infectious Disease
- Laboratory Methods
- Mosquito-borne Diseases
- Polymerase Chain Reaction
- Public Health
- RNA
- Vector-borne disease
- Virology
- West Nile Virus
Summary
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The research focused on a five-year investigation to track the prevalence of West Nile virus and Eastern equine encephalitis virus by testing mosquitos and sentinel chicken blood in Southeastern Virginia.
Study Methodology
- The Norfolk Department of Public Health’s Bureau of Laboratories carried out the research.
- Data was gathered each year from 2000 to 2004 from the southeastern region of Virginia.
- Mosquito pool supernatants and the sera of sentinel chickens were analyzed for the presence of the West Nile virus (WNV) and Eastern equine encephalitis virus (EEE).
- The research used conventional reverse transcription polymerase chain reaction (RT-PCR) and Taqman RT-PCR with the i-Cycler to screen for viral RNA in mosquito pool supernatants.
- Mosquito pools were also examined for virus activity using Vero cell culture.
Research Findings
- The primary transmitting vector (carrier) of West Nile virus was Culex (Cx.) pipiens and of Eastern equine encephalitis virus was Culiseta (Cs.) melanura.
- In the five-year surveillance period, the highest minimum infection rates (MIRs) in mosquitoes were observed in 2002 for WNV (2.7) and in 2001 for EEE (0.9).
- In 2003, the MIRs in Cs. melanura for WNV and EEE were 0.24 and 0.56 respectively, while the MIR for WNV in Cx. pipiens was 0.64.
- In 2004, Cs. melanura exhibited less WNV transmission activity (MIR = 0.07) compared to Cx. pipiens (MIR = 1.8). Cs. melanura was the only vector for EEE (MIR = 0.37).
Trends Observed
- The research found peak activities for the transmission of these viruses were usually summertime – EEE activity typically peaking in July; WNV activity peaking in August.
- Sentinel chicken sera were tested for IgM antibodies and peak seroconversions were recorded in August 2003 for WNV and in July 2003 for EEE. In 2004, high IgM seroconversions were later, occurring in August for EEE.
- The overall trend suggested virus activity was higher in 2003 than in 2004.
Cite This Article
APA
Loftin KC, Diallo AA, Herbert MW, Phaltankar PG, Yuan C, Grefe N, Flemming A, Foley K, Williams J, Fisher SL, Elberfeld M, Constantine J, Burcham M, Stallings V, Xia D.
(2006).
Five-year surveillance of West Nile and eastern equine encephalitis viruses in Southeastern Virginia.
J Environ Health, 68(9), 33-40.
Publication
Researcher Affiliations
- Norfolk Public Health Laboratory, Commonwealth of Virginia, Norfolk, VA 23510, USA.
MeSH Terms
- Animals
- Bird Diseases / epidemiology
- Bird Diseases / virology
- Chickens / virology
- Chlorocebus aethiops
- Culicidae / classification
- Culicidae / virology
- Encephalitis Virus, Eastern Equine / genetics
- Encephalitis Virus, Eastern Equine / isolation & purification
- Encephalomyelitis, Eastern Equine / epidemiology
- Encephalomyelitis, Eastern Equine / veterinary
- Encephalomyelitis, Eastern Equine / virology
- Insect Vectors / classification
- Insect Vectors / virology
- RNA, Viral / analysis
- Rain
- Sentinel Surveillance
- Temperature
- Vero Cells
- Virginia / epidemiology
- West Nile Fever / epidemiology
- West Nile Fever / veterinary
- West Nile Fever / virology
- West Nile virus / genetics
- West Nile virus / isolation & purification
Citations
This article has been cited 8 times.- Miranda J, Mattar S, Gonzalez M, Hoyos-López R, Aleman A, Aponte J. First report of Culex flavivirus infection from Culex coronator (Diptera: Culicidae), Colombia. Virol J 2019 Jan 3;16(1):1.
- Beckham JD, Tyler KL. Arbovirus Infections. Continuum (Minneap Minn) 2015 Dec;21(6 Neuroinfectious Disease):1599-611.
- Downs JA, Hyzer G, Marion E, Smith ZJ, Kelen PV, Unnasch TR. Mapping eastern equine encephalitis virus risk for white-tailed deer in Michigan. Appl Geogr 2015 Oct 1;64:66-73.
- Molaei G, Armstrong PM, Abadam CF, Akaratovic KI, Kiser JP, Andreadis TG. Vector-Host Interactions of Culiseta melanura in a Focus of Eastern Equine Encephalitis Virus Activity in Southeastern Virginia. PLoS One 2015;10(9):e0136743.
- Davis LE, Beckham JD, Tyler KL. North American encephalitic arboviruses. Neurol Clin 2008 Aug;26(3):727-57, ix.
- Savage HM, Aggarwal D, Apperson CS, Katholi CR, Gordon E, Hassan HK, Anderson M, Charnetzky D, McMillen L, Unnasch EA, Unnasch TR. Host choice and West Nile virus infection rates in blood-fed mosquitoes, including members of the Culex pipiens complex, from Memphis and Shelby County, Tennessee, 2002-2003. Vector Borne Zoonotic Dis 2007 Fall;7(3):365-86.
- Halliday JE, Meredith AL, Knobel DL, Shaw DJ, Bronsvoort BM, Cleaveland S. A framework for evaluating animals as sentinels for infectious disease surveillance. J R Soc Interface 2007 Oct 22;4(16):973-84.
- Cupp EW, Hassan HK, Yue X, Oldland WK, Lilley BM, Unnasch TR. West Nile virus infection in mosquitoes in the mid-south USA, 2002-2005. J Med Entomol 2007 Jan;44(1):117-25.
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