Mosquitoes collected in Prosser and West Richland have tested positive for West Nile virus -- the first sign this season that the virus is active in the county, Benton County Mosquito Control announced Wednesday.
"This is the time of year when disease transmission from mosquitoes to people, birds, and horses is the highest. It is extremely important that people wear repellent when outdoors over the next month," said Angela Beehler, the agency's manager, in a news release.
West Nile also has been found in mosquitoes in Franklin County.
Most people bitten by infected mosquitoes don't become sick, but West Nile can be serious and even fatal.
To reduce risk, people should stay inside at dusk and dawn, which are the most active time for mosquitoes, and also drain standing water on their property, wear long sleeves and pants outdoor when possible and use mosquito repellent, the news release said.