Effect of Trapping Methods, Weather, and Landscape on Estimates of the Culex Vector Mosquito Abundance

• Type of Material: Article
• Authors: Surendra Karki, University of Illinois; Gabriel L. Hamer, Texas A&M University; Tavis K. Anderson, National Animal Disease Center; Tony L. Goldberg, University of Wisconsin; Uriel Kitron, Emory University; Bethany L. Krebs, San Francisco Zoo; Edward D. Walker, Michigan State University; Marilyn O. Ruiz, University of Illinois
• Language: English
• Date: 2016
• Publisher: Libertas Academica
• Publication Version: Final Published Version
• Copyright Statement: © 2016 the author(s), publisher and licensee Libertas Academica Ltd.
• License: Creative Commons Attribution-Noncommercial 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.4137/EHI.S33384
• Title of Journal or Parent Work: Environmental Health Insights
• ISSN: 1178-6302
• Start Page: 93
• End Page: 93
• Grant/Funding Information: Funding was provided by the National Science Foundation and National Institutes of Health Ecology of Infectious Disease program under Award No. 0840403.; Additional funding was from the Stormwater and Mosquito Control Theme at the University of Illinois, Institute for Sustainability, Energy, and Environment.
• Keywords: Culex; light traps; gravid traps; landscape; arbovirus; weather; abundance; West Nile virus
• Research Categories: Environmental Sciences; Biology, Entomology; Health Sciences, Public Health

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.