West Nile Virus

West Nile Virus

West Nile virus (WNV) is a potentially serious illness. WNV has been established as a seasonal epidemic that generally runs June 1 to Nov. 1. Click on this interactive map to view reported WNV  cases across California.

To report a dead bird or squirrel call the West Nile Virus Dead Bird Hotline at 877-WNV-BIRD (877-968-2473). The Hotline is staffed with live operators. You may also use this online reporting form.

How WNV IS Spread to Humans?

WNV is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds. Human-to-human transmission of WNV does not occur. However, human WNV infections have been associated with blood transfusions and organ transplants.

Control Activities in Alameda County

As of Nov. 3, 2017, California reported 484 dead birds, 3,350 mosquito pools, and 427 humans that tested positive for the virus in 47 counties. Alameda County reported 1 human and 2 dead birds positive for WNV, and zero mosquito pools.

During WNV season, Alameda County’s Mosquito Abatement program works to limit risks to residents by monitoring ponds and other possible mosquito breeding sites; trapping to detect high numbers of mosquitoes; treating sewer catch-basins to prevent breeding; collecting birds for testing; and educating residents and owners about removing standing water from private property to limit mosquito breeding and mosquito bites.


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