Project title: A Comparison of West Nile Virus Vector Mosquito Populations in Sites With and Without Storm Water Drainage Ponds
Completed in: 2004
The spread of West Nile Virus (WNV) across the United States (US) over the past four years has lead to an increased awareness of the need for mosquito surveillance and abatement programs. Storm water drainage ponds are often blamed for mosquito problems, even though vector mosquitoes such as Culex (CX) pipiens have been shown to breed primarily in small containers such as planters, birdbaths and discarded tires, which are often associated with residential development. Storm water drainage ponds are frequently targeted for mosquito abatement efforts, even though their role in the maintenance and transmission of WNV has not been documented. Abatement strategies often include larviciding, which is both expensive, and potentially harmful for the environment.
In this study, adult and larval mosquitoes were trapped at selected areas in King County, WA during the summer of 2003. Weather and water quality data were collected and investigated for their influence on mosquito abundance. Trapping data was analyzed to determine whether or not populations of mosquitoes, particularly WNV vector species, show a significant increase with proximity to storm water drainage ponds. Our results indicate that there is a significant increase in vector mosquito populations associated with the presence of storm water ponds. The data was also analyzed to look for correlations between the land use characteristics of the sites, and the numbers and diversity of mosquitoes. This analysis showed an association between the degree of urbanization of the sites, and the number of mosquitoes trapped, particularly for Cx pipiens, with suburban areas have the highest prevalence of this important vector species.