As a result, Riverside County Vector Control workers are applying pesticide to pools and other potential mosquito breeding grounds. So far, pesticide has been applied at 87 locations.
West Nile virus is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds.
The risk of serious illness to humans is considered by experts to be low but people with weak immune systems and the elderly are at the greatest risk for developing serious illness.
