Amanda Zych

Project title: Identifying Mosquito Vector Species in Storm-water Drainage Ponds in King County, Washington

Degree: MS (Thesis) | Program: Environmental Health (EH) | Project type: Thesis/Dissertation
Completed in: 2003 | Faculty advisor: Charles D. (Chuck) Treser


The recent discovery of West Nile virus (WNV) in Washington State has heightened the concern about the disease and current knowledge of the mosquito vectors in our region is weak. Since the early 1970s, little work has been done on identifying mosquito populations either as nuisance species or possible vectors of disease in metropolitan King County. In order to prepare the region for a possible epidemic of disease transmitted by mosquitoes, it is essential to begin to identify the vector species found in the region. Awareness of the species distribution and of the habitats that support mosquito populations is necessary to develop proper prevention and control programs. This project will characterize the larval and adult mosquito populations in a portion of King County. The goal is to verify that within this area there exists a variety of mosquito species that have been show to be competent vectors of disease to humans. Furthermore, the distinctive habitats that mosquitoes were collected from will be described and correlated with the vector species that reside there. In this study, fifteen regional storm water drainage ponds and nearby catch basins within the County were visited monthly from April-October of 2002 and again in April of 2003. Both larvae and adult mosquitoes were collected. Larvae were dipped for in stagnant water and reared to adults in the laboratory. Adults were trapped in two EVS CO2 traps that were set overnight at each site. All collected mosquitoes were sent to the Washington State Department of Health to be speciated.

Thirteen total species along with six vector species were collected during the 2002 season. Further analysis on those species that have been shown in the literature to be vectors of WNV will be included looking at similarities in breeding habitat. This includes comparative analysis on environmental setting, habitat type, water permanence, pollution, high grasses, atmospheric conditions, and mosquito-eating fish. ArcView GIS was used to create a map showing vector species prevalence among the selected residential neighborhoods. While storm water drainage ponds are ecologically important, they increase habitat availability for potentially dangerous disease vectors. Surveillance is necessary to identify and document species presence, habitat preference and potential vectors among these anthropogenic habitats. This study will augment historic data and other current collection efforts to create a general picture of the mosquito populations in King County, Washington.