Volume 78, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


We collected a total of 15,329 mosquitoes during weekly sampling in Davis, CA, from April through mid-October 2006 at 21 trap sites uniformly spaced 1.5 km apart over an area of ∼26 km. Of these mosquitoes, 1,355 pools of spp. were tested by multiplex reverse transcriptase-polymerase chain reaction, of which 16 pools (1.2%) were positive for West Nile virus (WNV). A degree-day model with a developmental threshold of 14.3°C accurately predicted episodic WNV transmission after three extrinsic incubation periods after initial detection. Kriging interpolation delineated that were most abundant at traps near surrounding agriculture, whereas clustered within residential areas and greenbelt systems in the old portion of Davis. Spatial-temporal analyses were performed to test for clustering of locations of WNV-infected dead birds and traps with WNV-positive and ; human case incidence was mapped by census blocks. Significant multivariate spatial-temporal clustering was detected among WNV-infected dead birds and WNV-positive and a WNV-positive cluster overlapped areas with high incidences of confirmed human cases. Spatial analyses of WNV surveillance data may be an effective method to identify areas with an increased risk for human infection and to target control efforts to reduce the incidence of human disease.


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  1. Komar N, 2003. West Nile virus: epidemiology and ecology in North America. Adv Virus Res 61 : 185–234. [Google Scholar]
  2. Hayes CG, 1989. West Nile fever. Monath TP, ed. The Arboviruses: Epidemiology and Ecology. Boca Raton, FL: CRC Press, 59–88.
  3. Hayes EB, Sejvar JJ, Zaki SR, Lanciotti RS, Bode AV, Campbell GL, 2005. Virology, pathology, and clinical manifestations of West Nile virus disease. Emerg Infect Dis 11 : 1174–1179. [Google Scholar]
  4. CDC, 2006. West Nile virus: statistics, surveillance and control. Available at: http://www.cdc.gov/ncidod/dvbid/westnile/surv&control.htm. Accessed February 10, 2007.
  5. CDC, 2001 West Nile virus, mosquitoes, USA: update. Available at: www.promedmail.org. Accessed November 2, 2006.
  6. Theophilides CN, Ahearn SC, Grady S, Merlino M, 2003. Identifying West Nile virus risk areas: the Dynamic Continuous-Area Space-Time system. Am J Epidemiol 157 : 843–854. [Google Scholar]
  7. Reisen WK, Barker CM, Carney R, Lothrop HD, Wheeler SS, Wilson JL, Madon MB, Takahashi R, Carroll B, Garcia S, Fang Y, Shafii M, Kahl N, Ashtari S, Kramer V, Glaser C, Jean C, 2006. Role of corvids in epidemiology of West Nile virus in southern California. J Med Entomol 43 : 356–367. [Google Scholar]
  8. Watson JT, Jones RC, Gibbs K, Paul W, 2004. Dead crow reports and location of human West Nile virus cases, Chicago, 2002. Emerg Infect Dis 10 : 938–940. [Google Scholar]
  9. Eidson M, Schmit K, Hagiwara Y, Anand M, Backenson PB, Gotham I, Kramer L, 2005. Dead crow density and West Nile virus monitoring, New York. Emerg Infect Dis 11 : 1370–1375. [Google Scholar]
  10. Brownstein JS, Rosen H, Purdy D, Miller JR, Merlino M, Mostashari F, Fish D, 2002. Spatial analysis of West Nile virus: rapid risk assessment of an introduced vector-borne zoonosis. Vector Borne Zoonotic Dis 2 : 157–164. [Google Scholar]
  11. Ruiz MO, Tedesco C, McTighe TJ, Austin C, Kitron U, 2004. Environmental and social determinants of human risk during a West Nile virus outbreak in the greater Chicago area, 2002. Int J Health Geogr 3 : 8. [Google Scholar]
  12. 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. [Google Scholar]
  13. Ruiz MO, Walker ED, Foster ES, Haramis LD, Kitron UD, 2007. Association of West Nile virus illness and urban landscapes in Chicago and Detroit. Int J Health Geogr 6 : 10. [Google Scholar]
  14. Hayes EB, Komar N, Nasci RS, Montgomery SP, O’Leary DR, Campbell GL, 2005. Epidemiology and transmission dynamics of West Nile virus disease. Emerg Infect Dis 11 : 1167–1173. [Google Scholar]
  15. Reisen WK, Lothrop HD, Chiles RE, Madon MB, Cossen C, Woods L, Husted S, Kramer VL, Edman JD, 2004. West Nile virus in California. Emerg Infect Dis 10 : 1369–1378. [Google Scholar]
  16. Hom A, Marcus L, Kramer VL, Cahoon B, Glaser C, Cossen C, Baylis E, Jean C, Tu E, Eldridge BF, Carney R, Padgett K, Sun B, Reisen WK, Woods L, Husted S, 2005. Surveillance for mosquito-borne encephalitis virus activity and human disease, including West Nile virus, in California, 2004. Proc Mosq Vector Control Assoc Calif 73 : 66–77. [Google Scholar]
  17. Elnaiem DA, Kelly K, Wright S, Laffey R, Yoshimura G, Armijos V, Reed M, Farley M, Goodman G, Reisen WK, Brown D, 2006. Epidemic amplification of West Nile Virus in Sacramento and Yolo Counties, June-September 2005. Proc Mosq Vector Control Assoc Calif 74 : 18–20. [Google Scholar]
  18. Nielsen CF, Reisen WK, Armijos MV, MacLachlan NJ, Scott TW, 2008. High subclinical West Nile virus incidence among non-vaccinated horses in Northern California associated with low vector abundance and infection. Am J Trop Med Hyg 78 : 45–52. [Google Scholar]
  19. Goddard LB, Roth AE, Reisen WK, Scott TW, 2002. Vector competence of California mosquitoes for West Nile virus. Emerg Infect Dis 8 : 1385–1391. [Google Scholar]
  20. Reisen WK, Fang Y, Martinez VM, 2006. Vector competence of Culiseta incidens and Culex thriambus for West Nile virus. J Am Mosq Control Assoc 22 : 662–665. [Google Scholar]
  21. 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. [Google Scholar]
  22. 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, Reisen WK, Woods L, Glover J, Erickson C, Barclay C, Husted S, 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. [Google Scholar]
  23. Reeves WC, Asman SM, Hardy JL, Milby MM, Reisen WK, 1990. Epidemiology and Control of Mosquito-Borne Arboviruses in California, 1943–1987. Sacramento, CA: California Mosq Vector Control Assoc.
  24. Tempelis CH, Washino RK, 1967. Host-feeding patterns of Culex tarsalis in the Sacramento Valley, California, with notes on other species. J Med Entomol 4 : 315–318. [Google Scholar]
  25. Tempelis CH, Reeves WC, Bellamy RE, Lofy MF, 1965. A three-year study of the feeding habits of Culex tarsalis in Kern County, California. Am J Trop Med Hyg 14 : 170–177. [Google Scholar]
  26. Reisen WK, Reeves WC, 1990. Bionomics and Ecology of Culex tarsalis and Other Potential Mosquito Vector Species. Epidemiology and Control of Mosquito-Borne Arboviruses in California, 1943–1987. Sacramento, CA: California Mosq Vector Control Assoc.
  27. Gubler DJ, Campbell GL, Nasci R, Komar N, Petersen L, Roehrig JT, 2000. West Nile virus in the United States: guidelines for detection, prevention, and control. Viral Immunol 13 : 469–475. [Google Scholar]
  28. Rohe DL, Fall RP, 1979. A miniature battery powered CO2-baited trap for mosquito borne encephalitis surveillance. Bull Soc Vector Ecol 4 : 24–27. [Google Scholar]
  29. Reisen WK, Boyce K, Cummings RF, Delgado O, Gutierrez A, Meyer RP, Scott TW, 1999. Comparative effectiveness of three adult mosquito sampling methods in habitats representative of four different biomes of California. J Am Mosq Control Assoc 15 : 24–31. [Google Scholar]
  30. Tempelis CH, 1970. Host preferences of mosquitoes. Proc Mosq Cont Assoc Calif 38 : 25–28. [Google Scholar]
  31. Urbanelli S, Silvestrini F, Reisen WK, deVito E, Bullini L, 1997. California hybrid zone between Culex pipiens pipiens and Cx. p. quinquefasciatus revisited (Diptera: Culicidae). J Med Entomol 34 : 116–127. [Google Scholar]
  32. Cummings RF, 1992. Design and use of a modified Reiter gravid mosquito trap for mosquito-borne encephalitis surveillance in Los Angeles County, California. Proc Mosq Vector Control Assoc Calif 60 : 170–176. [Google Scholar]
  33. Reiter P, 1983. A portable, battery-powered trap for collecting gravid Culex mosquitoes. Mosq News 43 : 496–498. [Google Scholar]
  34. Kitron U, 1998. Landscape ecology and epidemiology of vector-borne diseases: tools for spatial analysis. J Med Entomol 35 : 435–445. [Google Scholar]
  35. Moore JE, Switzer PV, 1998. Preroosting aggregations in the American crow, Corvus brachyrhyncos. Can J Zool 76 : 508–512. [Google Scholar]
  36. Sauer JR, Hines JE, Fallon J, 2005. The North American Breeding Bird Survey, Results and Analysis 1966–2005. Version 6.2.2006. Laurel, MD: USGS Patuxent Wildlife Research Center.
  37. Reisen WK, Milby MM, Meyer RP, Pfuntner AR, Spoehel J, Hazelrigg JE, Webb JP, 1991. Mark-release-recapture studies with Culex mosquitoes (Diptera: Culicidae) in southern California. J Med Entomol 28 : 357–371. [Google Scholar]
  38. Kramer VL, 2005. California State Mosquito-Borne Virus Surveillance and Response Plan. Sacramento, CA: California Department of Health Services.
  39. Lanciotti RS, Kerst AJ, Nasci RS, Godsey MS, Mitchell CJ, Savage HM, Komar N, Panella NA, Allen BC, Volpe KE, Davis BS, Roehrig JT, 2000. Rapid detection of West Nile Virus from human clinical specimens, field-collected mosquitoes, and avian samples by a TaqMan reverse transcriptase-PCR assay. J Clin Microbiol 38 : 4066–4071. [Google Scholar]
  40. 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 Cont Assoc Calif 72 : 15–17. [Google Scholar]
  41. Simmons K, Fang Y, Dannen M, Reisen WK, 2007. Proficiency panels—accuracy, specificity, and sensitivity results with implications for risk assessment. Proc Mosq Vector Cont Assoc Calif 75 : 38–42. [Google Scholar]
  42. Biggerstaff BJ, 2003. Pooled Infection Rate. Ft. Collins, CO: Centers for Disease Control and Prevention.
  43. Moore DA, Carpenter TE, 1999. Spatial analytical methods and geographic information systems: use in health research and epidemiology. Epidemiol Rev 21 : 143–161. [Google Scholar]
  44. Eidson M, Miller J, Kramer L, Cherry B, Hagiwara Y, 2001. Dead crow densities and human cases of West Nile virus, New York State, 2000. Emerg Infect Dis 7 : 662–664. [Google Scholar]
  45. Caccamise DF, Reed LM, Romanowski J, Stouffer PC, 1997. Roosting behavior and group territoriality in American crows. Auk 114 : 628–637. [Google Scholar]
  46. Meyer RP, Hardy JL, Reisen WK, 1990. Diel changes in adult mosquito microhabitat temperatures and their relationship to the extrinsic incubation of arboviruses in mosquitoes in Kern County, California, U.S.A. J Med Entomol 27 : 607–614. [Google Scholar]
  47. Nielsen CF, Reisen WK, 2007. West Nile virus-infected dead corvids increase the risk of infection in Culex mosquitoes (Diptera: Culicidae) in domestic landscapes. J Med Entomol 44 : 1067–1073. [Google Scholar]
  48. Johnson GD, Eidson M, Schmit K, Ellis A, Kulldorff M, 2006. Geographic prediction of human onset of West Nile virus using dead crow clusters: an evaluation of year 2002 data in New York State. Am J Epidemiol 163 : 171–180. [Google Scholar]
  49. Turell MJ, Sardelis MR, Dohm DJ, O’Guinn ML, 2001. Potential North American vectors of West Nile virus. Ann N Y Acad Sci 951 : 317–324. [Google Scholar]
  50. Richards SL, Apperson CS, Ghosh SK, Cheshire HM, Zeichner BC, 2006. Spatial analysis of Aedes albopictus (Diptera: Culicidae) oviposition in suburban neighborhoods of a Piedmont community in North Carolina. J Med Entomol 43 : 976–989. [Google Scholar]
  51. Petersen LR, Marfin AA, 2002. West Nile virus: a primer for the clinician. Ann Intern Med 137 : 173–179. [Google Scholar]
  52. Nielsen CF, Reisen WK, Armijos V, Wheeler S, Kelley K, Brown D, 2007. Impact of climate variation and adult mosquito control on the West Nile virus epidemic in Davis, California during 2006. Proc Mosq Vector Control Assoc Calif. 75 : 132–137. [Google Scholar]

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  • Received : 14 Jul 2007
  • Accepted : 16 Oct 2007

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