Two dead crows infected with West Nile virus were found in Santa Rosa, the Marin/Sonoma Mosquito and Vector Control District announced Tuesday.
One bird was found near Occidental Road and Irwin Lane and the other was found near Barnes Road and Dennis Lane.
"All known mosquito breeding sources are being monitored, and technicians are combing the area in search of other sites that may be producing mosquitos," said Erik Hawk, assistant manager of the Marin/Sonoma Mosquito and Vector Control District in a statement.
West Nile virus is a mosquito-borne disease spread by the insect's bite. Residents can help reduce the threat by eliminating standing water in rain barrels, old tires, pools and elsewhere.