The Department of Health Services said Monday residents should use caution as dead birds can indicate infected mosquitoes are in the area. Residents can limit risk of infection by avoiding standing pools of water and by using bug repellant.
West Nile virus spreads to birds, animals and people through the bites of infected mosquitoes. Mosquitoes get the virus by feeding on infected birds.
There were 16 confirmed cases of West Nile virus in humans in Wisconsin last year. State data show cases are reported most heavily in August and September.
Symptoms from the potentially fatal virus include fever, headaches, swollen lymph glands and body aches.