Routine trapping and surveillance by the St. Charles County Division of Environmental Health and Protection's Mosquito Control program has detected a positive test result for West Nile virus from mosquitoes within the county. There have been no positive cases of West Nile in humans reported this year. Program staff notes there is no reason for alarm from these findings but reminds residents to remain vigilant with efforts to prevent mosquito bites by wearing repellent when outdoors.

"Our staff has been aware of the presence of West Nile virus around the metropolitan area and has been trapping and testing mosquitoes all summer," says Seth Otto V, Mosquito Control Program Coordinator. "Following this positive indication in our community, our staff will increase treatment efforts aimed at reducing the risk for exposure to residents. Staff also reminds residents about the importance of taking steps to "Block the Bite" whenever outdoors this summer and fall."

This is the fifth consecutive year that St. Charles County has utilized collection traps to analyze mosquito populations. Traps have been placed in various locations throughout the county since June and will remain in place through September. Staff checks traps and analyzes collected mosquitoes on a weekly basis to determine the presence of various insect species and incidences of the virus.

"By using information from these collection sites, our staff can target areas with specific recommended treatment activity," notes Otto. "Different species of mosquito behave differently, so knowing the species at a location enables our staff to be more effective in controlling mosquito-borne disease."

What Should Residents Do to “Block the Bite”?

To minimize exposure to mosquito bites, Mosquito Control staff recommends residents:

Use insect repellent when outdoors. Repellents containing DEET, picaridin, IR3535 or oil of lemon eucalyptus are proven to provide protection when used according to manufacturer's recommendations. When also using sunscreen, apply the sunscreen first, let it dry, and then apply repellent.

Limit time outdoors when mosquitoes are most active ñ during dusk and dawn hours.

Wear light-colored, long-sleeved shirts and long pants when in traditional mosquito habitat such as wooded areas or tall grass.

Drain areas around the home that may hold water for five days or longer. Common sites include clogged gutters, pool covers, potted plant, bird baths and tire swings.

What Does St. Charles County Do to Prevent Nuisance Mosquito Populations?

The Division of Environmental Health and Protection contracts with several St. Charles County municipalities to investigate and control mosquito populations. Mosquito Control staff monitors for larval and adult insect activity, sets traps to test for the presence of different species and the diseases they may carry, and shares information on the most effective methods for protecting the public. The Mosquito Control staff also treats habitat areas to prevent larvae from developing into adult insects and performs targeted spraying in areas where a high population of disease-carrying or nuisance mosquitoes is observed.

Residents who live in unincorporated St. Charles County or within the city limits of Augusta, Cottleville, Flint Hill, Lake Saint Louis, Portage des Sioux, St. Paul, Weldon Spring, Weldon Spring Heights and Wentzville should use the CitizenServe online portal at sccmo.org/mosquito to request treatment by Mosquito Control staff. Those who wish to add their address to a "No Spray" list can call 636-949-1800. Residents living within the city limits of Dardenne Prairie, O'Fallon, St. Charles and St. Peters should contact their respective city halls for treatment concerns.