Mosquito-borne encephalitis viruses are endemic zoonoses that continue to pose a health risk to the residents of California and other affected areas of the United States. Our proposed research investigates how vertebrate and invertebrate host-virus relationships may affect the force of transmission and virus persistence. Experiments compare the responses of different avian host species and the primary vector mosquito, Culex tarsalis, to infection with the Alphavirus western equine encephalomyelitis virus (WEE) and the Flavivirus St. Louis encephalitis virus (SLE) and investigate how these interactions may lead to the introduction or emergence of new viral genotypes. Research addresses the following interrelated specific hypothesis: 1. Vertebrate host competence factors of survival, viremia and antibody production impact the force of WEE and SLE transmission. Experimental infection studies will compare the viremia responses of avian species that are abundant and have relatively high, low or negative seroprevalence rates in nature. 2. Virus infection negatively affects the vector competence and bionomics of Cx. tarsalis. The impact of the infecting dose of WEE and SLE on mosquito pathology, susceptibility to infection, transmission, life table parameters and flight behavior will be assessed experimentally using colonies selected for increased and decreased susceptibility to infection. 3. WEE and SLE respond to vertebrate and vector host defenses by establishing chronic infections and/or by changing genetically. Experiments will attempt to establish chronic infections in representative resident and migrant bird species to assess their ability to maintain virus overwinter, to disperse virus to new susceptible populations, or to alter virus genetics. Studies will assess how alternating sequential infections between vertebrate and vector species that are part of the natural transmission cycle may alter virus genetics and fitness.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI047855-02
Application #
6374560
Study Section
Special Emphasis Panel (ZRG1-TMP (01))
Program Officer
Meegan, James M
Project Start
2000-08-01
Project End
2004-07-31
Budget Start
2001-08-01
Budget End
2002-07-31
Support Year
2
Fiscal Year
2001
Total Cost
$371,879
Indirect Cost
Name
University of California Davis
Department
Veterinary Sciences
Type
Schools of Veterinary Medicine
DUNS #
094878337
City
Davis
State
CA
Country
United States
Zip Code
95618
Reisen, William K; Wheeler, Sarah S; Garcia, Sandra et al. (2010) Migratory birds and the dispersal of arboviruses in California. Am J Trop Med Hyg 83:808-15
Ciota, Alexander T; Lovelace, Amy O; Jia, Yongqing et al. (2008) Characterization of mosquito-adapted West Nile virus. J Gen Virol 89:1633-42
Reisen, William K; Fang, Ying; Brault, Aaron C (2008) Limited interdecadal variation in mosquito (Diptera: Culicidae) and avian host competence for Western equine encephalomyelitis virus (Togaviridae: Alphavirus). Am J Trop Med Hyg 78:681-6
Ciota, Alexander T; Lovelace, Amy O; Ngo, Kiet A et al. (2007) Cell-specific adaptation of two flaviviruses following serial passage in mosquito cell culture. Virology 357:165-74
Ciota, Alexander T; Lovelace, Amy O; Jones, Susan A et al. (2007) Adaptation of two flaviviruses results in differences in genetic heterogeneity and virus adaptability. J Gen Virol 88:2398-406
Reisen, William K; Fang, Ying (2007) Does feeding on infected mosquitoes (Diptera: Culicidae) enhance the role of song sparrows in the transmission of arboviruses in California? J Med Entomol 44:316-9
Reisen, William K; Hahn, D Caldwell (2007) Comparison of immune responses of brown-headed cowbird and related blackbirds to west Nile and other mosquito-borne encephalitis viruses. J Wildl Dis 43:439-49
Ciota, Alexander T; Ngo, Kiet A; Lovelace, Amy O et al. (2007) Role of the mutant spectrum in adaptation and replication of West Nile virus. J Gen Virol 88:865-74
Reisen, William K; Martinez, Vincent M; Fang, Ying et al. (2006) Role of California (Callipepla californica) and Gambel's (Callipepla gambelii) quail in the ecology of mosquito-borne encephalitis viruses in California, USA. Vector Borne Zoonotic Dis 6:248-60
Chiles, Robert E; Green, Emily N; Fang, Ying et al. (2004) Blinded laboratory comparison of the in situ enzyme immunoassay, the VecTest wicking assay, and a reverse transcription-polymerase chain reaction assay to detect mosquitoes infected with West Nile and St. Louis encephalitis viruses. J Med Entomol 41:539-44

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