title: Effect of Trapping Methods, Weather, and Landscape on Estimates of the Culex Vector Mosquito Abundance.
abstract: The local abundance of Culex mosquitoes is a central factor adding to the risk of West Nile virus transmission, and vector abundance data influence public health decisions. This study evaluated differences in abundance estimates from mosquitoes trapped using two common methods: CO2-baited CDC light traps and infusion-baited gravid traps in suburban, Chicago, Illinois. On a weekly basis, the two methods were modestly correlated (r = 0.219) across 71 weeks over 4 years. Lagged weather conditions of up to four weeks were associated with the number of mosquitoes collected in light and gravid traps. Collections in light traps were higher with higher temperature in the same week, higher precipitation one, two, and four weeks before the week of trapping, and lower maximum average wind speed. Collections in gravid traps were higher with higher temperature in the same week and one week earlier, lower temperature four weeks earlier, and with higher precipitation two and four weeks earlier. Culex abundance estimates from light traps were significantly higher in semi-natural areas compared to residential areas, but abundance estimates from gravid traps did not vary by the landscape type. These results highlight the importance of the surveillance methods used in the assessment of local Culex abundance estimates. Measures of risk of exposure to West Nile virus should assess carefully how mosquito abundance has been estimated and integrated into assessments of transmission risk.
authors.affiliation: Department of Pathobiology, University of Illinois, Urbana-Champaign, IL, USA.
authors.forename: Surendra
authors.initials: S
authors.lastname: Karki
authors.affiliation: Department of Entomology, Texas A&M University, College Station, TX, USA.
authors.forename: Gabriel L
authors.initials: GL
authors.lastname: Hamer
authors.affiliation: Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA.
authors.forename: Tavis K
authors.initials: TK
authors.lastname: Anderson
authors.affiliation: Department of Pathobiological Sciences, University of Wisconsin, Madison, WI, USA.
authors.forename: Tony L
authors.initials: TL
authors.lastname: Goldberg
authors.affiliation: Department of Environmental Studies, Emory University, Atlanta, GA, USA.
authors.forename: Uriel D
authors.initials: UD
authors.lastname: Kitron
authors.affiliation: Wellness and Animal Behavior Department, San Francisco Zoo, San Francisco, CA, USA.
authors.forename: Bethany L
authors.initials: BL
authors.lastname: Krebs
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, Lansing, MI, USA.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Walker
authors.affiliation: Department of Pathobiology, University of Illinois, Urbana-Champaign, IL, USA.
authors.forename: Marilyn O
authors.initials: MO
authors.lastname: Ruiz
keywords: Culex; West Nile virus; abundance; arbovirus; gravid traps; landscape; light traps; weather