Surveillance – Adult and Larval

Cowlitz County Mosquito Control District utilizes a number of surveillance methods: Technicians go out in the field to sample standing water for mosquito larva, collect larval samples for identification and larval counts.  This allows the technicians to apply the best control measure for larva. Lab Technicians trap and identify the populations and specific species of adult mosquitoes. Lab Technicians test adult mosquito samples for West Nile Virus using the RAMP test in the district lab and maintain collection data on mosquitoes and mosquito-borne diseases. CCMCD routinely communicates with other regional mosquito districts, sharing information about mosquito populations and species as an important part of surveillance. CCMCD reports all trapping data including RAMP test results to the Zoonotic Disease Program, and Washington State Department of Health.

Larval Surveillance

Immature mosquito surveillance can provide early warning to forecast the size of future adult mosquito populations and provide estimates of control effectiveness. The data collected from dipping immature mosquito breeding sites are recorded and maintained. The sites that are found positive for mosquitoes will be mapped by Global Positioning System (GPS). The mosquitoes collected are brought to the CCMCD laboratory for identification. When sufficient data is obtained, the information will be utilized in the control process.

Adult Mosquitoes Surveillance and Testing

Monitoring adult mosquito populations provides essential information on population size, infectivity rate and effectiveness of larval and adult control efforts. The primary method used by CCMCD to sample adult mosquito populations is the EVS trap. CCMCD has predetermined locations for placement of these traps, mapped using GPS. The mosquitoes collected in these traps will be returned to the CCMCD laboratory for identification and WNV testing using a RAMP test. All trapping data and test results are reported to the Zoonotic Disease Program / Washington State Department of Health (DOH). Results from these tests will be a key factor in determining the areas requiring adult control measures.