1921
Volume 78, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645

Abstract

Historically, western equine encephalomyelitis virus (WEEV) caused large equine and human epidemics in the Americas from Canada into Argentina. Despite recent enhanced surveillance for West Nile virus, there have been few reports of equine or human cases and little documented enzootic activity of WEEV. During the past three years, WEEV has been active again in California, but without human or equine cases. In the current study, we compared host and vector competence of representative WEEV isolates made during each decade over the past 60 years using white-crowned sparrows, house sparrows, and Coquillett as representative hosts. Results indicated limited time-related change in virulence among WEEV strains in birds and little difference in vector competence in . Although temporal and spatial genetic changes have been documented, these seem to present limited phenotypic change in host competence and cannot explain the absence of equine and human cases.

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2008-04-01
2017-09-20
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References

  1. Reisen WK, Monath TP, 1989. Western equine encephalomyelitis. Monath TP, ed. The Arboviruses: Epidemiology and Ecology. Boca Raton, FL: CRC Press, 89–138.
  2. Meyer KF, Haring CM, Howitt B, 1931. The etiology of epizootic encephalomyelitis of horses in the San Joaquin Valley, 1930. Science 74 : 227–228.
  3. Howitt BF, 1938. Recovery of the virus of equine encephalomyelitis from the brain of a child. Science 88 : 455.
  4. Howitt BF, 1939. Viruses of equine and St. Louis encephalitis in relationship to human infections in California 1937–1938. Am J Public Health 29 : 1083–1097.
  5. Reeves WC, Hammon WM, 1962. Epidemiology of the arthropodborne viral encephalitides in Kern County, California, 1943–1952. Univ Calif Berkeley Publication Public Health 4 : 1–257.
  6. Reeves WC, Milby MM, 1989. Changes in transmission patterns of mosquito-borne viruses in the U.S.A. Service MW, ed. Demography and Vector-Borne Diseases. Boca Raton, FL: CRC Press, 121–141.
  7. Gahlinger PM, Reeves WC, Milby MM, 1986. Air conditioning and television as protective factors in arboviral encephalitis risk. Am J Trop Med Hyg 35 : 601–610.
  8. Reeves WC, ed., 1990. Epidemiology and Control of Mosquito-Borne Arboviruses in California, 1943–1987. Sacramento, CA: California Mosquito Vector Control Association.
  9. Reisen WK, Hardy JL, Reeves WC, Presser SB, Milby MM, Meyer RP, 1990. Persistence of mosquito-borne viruses in Kern County, California, 1983–1988. Am J Trop Med Hyg 43 : 419–437.
  10. Reisen WK, Boyce K, Yoshimura G, Lemenager D, Emmons RW, 1995. Enzootic transmission of western equine encepha-lomyelitis virus in the Sacramento Valley of California during 1993 and 1994. J Vector Ecol 20 : 153–163.
  11. Reisen WK, Chiles RE, 1997. Prevalence of antibodies to western equine encephalomyelitis and St. Louis encephalitis viruses in residents of California exposed to sporadic and consistent enzootic transmission. Am J Trop Med Hyg 57 : 526–529.
  12. Morales MA, Barrandeguy M, Fabbri C, Garcia JB, Vissani A, Trono K, Gutierrez G, Pigretti S, Menchaca H, Garrido N, Taylor N, Fernandez F, Levis S, Enria D, 2006. West Nile virus isolation from equines in Argentina, 2006. Emerg Infect Dis 12 : 1559–1561.
  13. Kramer LD, Fallah HM, 1999. Genetic variation among isolates of western equine encephalomyelitis virus from California. Am J Trop Med Hyg 60 : 708–713.
  14. Hardy JL, Reeves WC, 1990. Experimental studies on infection in vertebrate hosts. Reeves WC, ed. Epidemiology and Control of Mosquito-Borne Arboviruses in California, 1943–1987. Sacramento, CA: Calif. Mosq. Vector Control Association, 66–127.
  15. Hardy JL, Presser SB, Chiles RE, Reeves WC, 1997. Mouse and baby chicken virulence of enzootic strains of western equine encephalomyelitis virus from California. Am J Trop Med Hyg 57 : 240–244.
  16. Reisen WK, Kramer LD, Chiles RE, Martinez VM, Eldridge BF, 2000. Response of house finches to infection with sympatric and allopatric strains of western equine encephalomyelitis and St. Louis encephalitis viruses. J Med Entomol 37 : 259–264.
  17. Reisen WK, Chiles RE, Martinez VM, Fang Y, Green EN, 2003. Experimental infection of California birds with western equine encephalomyelitis and St. Louis encephalitis viruses. J Med Entomol 40 : 968–982.
  18. Hardy JL, 1987. The ecology of western equine encephalomyelitis virus in the Central Valley of California, 1945–1985. Am J Trop Med Hyg 37 : 18s–32s.
  19. Carroll B, Takahashi RM, Barker CM, Reisen WK, 2006. The reappearance of West Nile Virus in Kern County during 2005. Proc Mosq Vector Control Assoc Calif 74 : 12–15.
  20. Carroll BD, Takahashi RM, Reisen WK, 2007. West Nile virus activity in Kern County during 2006. Proc Mosq Vector Control Assoc Calif 75 : 17–22.
  21. Reisen WK, Lothrop HD, Wheeler SS, Kensington M, Gutierrez A, Fang Y, Garcia S, Lothrop B, 2008. Persistent West Nile virus transmission and the displacement of St. Louis encephalitis virus in southeastern California, 2003–2006. J Med Entomol (in press).
  22. Allison AB, Mead DG, Gibbs SE, Hoffman DM, Stallknecht DE, 2004. West Nile virus viremia in wild rock pigeons. Emerg Infect Dis 10 : 2252–2255.
  23. Hardy JL, Reeves WC, 1990. Experimental studies on infection in vectors. Reeves WC, ed. Epidemiology and Control of Mosquito-Borne Arboviruses in California, 1943–1987. Sacramento, CA: California Mosquito Vector Control Association, 145–250.
  24. Reeves WC, Milby MM, 1990. Natural infection in arthropod vectors. In: Reeves WC, ed. Epidemiology and Control of Mosquito-Borne Arboviruses in California, 1943–1987. Sacramento, CA: California Mosquito Vector Control Association, 128–144.
  25. Aitken TH, 1977. An in vitro feeding technique for artificially demonstrating virus transmission by mosquitoes. Mosq News 37 : 130–133.
  26. Chiles RE, Green EN, Fang Y, Reisen WK, Edman JD, Brault AC, 2004. Surveillance for arboviruses in California mosquito pools: current and future protocols. Proc Mosq Vector Control Assoc Calif 72 : 15–17.
  27. Kramer LD, Wolfe TM, Green EN, Chiles RE, Fallah H, Fang Y, Reisen WK, 2002. Detection of encephalitis viruses in mosquitoes (Diptera: Culicidae) and avian tissues. J Med Entomol 39 : 312–323.
  28. Chiles RE, Reisen WK, 1998. A new enzyme immunoassay to detect antibodies to arboviruses in the blood of wild birds. J Vector Ecol 23 : 123–135.
  29. Reisen WK, Chiles RE, Lothrop HD, Presser SB, Hardy JL, 1996. Prevalence of antibodies to mosquito-borne encephalitis viruses in residents of the Coachella Valley. Am J Trop Med Hyg 55 : 667–671.
  30. Hintze JL, 1998. NCSS Statistical Software 2000. Kaysville, UT: NCSS.
  31. Reisen WK, Lothrop HD, Presser SB, Milby MM, Hardy JL, Wargo WJ, Emmons RW, 1995. Landscape ecology of arboviruses in southern California: temporal and spatial patterns of vector and virus activity in Coachella Valley, 1990–1992. J Med Entomol 32 : 255–266.
  32. Hardy JL, Roberts DR, Banks RC, 1965. The composition of a wintering population of white-crowned sparrows in Kern County, California. Condor 67 : 90–91.
  33. Reisen WK, Fang Y, Martinez VM, 2005. Avian host and mosquito (Diptera: Culicidae) vector competence determine the efficiency of West Nile and St. Louis encephalitis virus transmission. J Med Entomol 42 : 367–375.
  34. Reisen WK, Fang Y, Martinez VM, 2006. Effects of temperature on the transmission of West Nile virus by Culex tarsalis (Diptera: Culicidae). J Med Entomol 43 : 309–317.
  35. Feiszli T, Park B, Kramer VL, Kjemtrup A, Eldridge BF, Fang Y, Reisen WK, Baylis E, Jean C, Glover J, Carney R, Padgett K, Erickson C, Husted S, 2007. Surveillance for mosquito-borne encephalitis virus activity in California, 2006. Proc Mosq Vector Control Assoc Calif 75 : 48–59.
  36. Hom A, Bonilla D, Kjemtrup A, Kramer VL, Cahoon-Young B, Barker CM, Marcus L, Glaser C, Cossen C, Baylis E, Jean C, Eldridge BF, Carney R, Padgett K, Sun B, 2006. Surveillance for mosquito-borne encephalitis virus activity and human disease, including West Nile virus, in California, 2005. Proc Mosq Vector Control Assoc Calif 74 : 43–55.
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  • Received : 10 Nov 2007
  • Accepted : 26 Jan 2008

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