The first mosquitoes of the season to test positive for the West Nile virus in DuPage County were collected this week in a trap in Lemont, health department officials said Friday.
Officials said the mosquitoes were collected Wednesday and tested Thursday.
No human cases of West Nile virus have been reported so far this year in DuPage.
The cool, wet spring delayed the development of the mosquitoes that spread the virus, health department officials said.
DuPage residents may track West Nile virus in their communities at dupagehealth.org/wnv-map. The map of mosquito traps throughout the county will be updated as mosquitoes test positive for the virus.
The health department also is collecting freshly dead birds, such as crows or blue jays, for testing. The birds may not show any signs of trauma or decay. In addition, the bird must be able to be picked up in time to be shipped to the state lab by the close of business on Thursdays. To report a dead bird, call (630) 682-7400.
Only about two people in 10 who are bitten by an infected mosquito will have symptoms. People older than 50 have the highest risk of severe illness.
Last year, the first human case of West Nile virus in DuPage was reported Aug. 31.
To help prevent West Nile virus, avoid being outdoors at dawn and dusk; wear long pants, long sleeves, shoes and socks; apply insect repellent; repair or replace damaged screens; and eliminate sources of standing water around your home.