Contra Costa County has reported its first avian case of West Nile virus (WNV) for 2025, indicating the virus's persistence in the region. A California scrub jay from San Ramon was confirmed infected by the Contra Costa Mosquito and Vector Control District, or the District. With infected birds acting as early indicators of the virus's spread, residents are on alert, not just in Contra Costa but also in Alameda and Santa Clara Counties, where WNV-positive birds have been found.
"We typically start seeing West Nile-positive birds and mosquitoes in Contra Costa County around this time of year," Dr. Steve Schutz, the District's Scientific Program Manager, explained via the Contra Costa Mosquito and Vector Control District news release. "Our neighboring counties have been reporting positive samples for several weeks now," he emphasized. As temperatures rise, so does the risk of human West Nile cases. To tackle the problem proactively, local health officials are stressing the importance of community engagement in controlling the mosquito population and reducing the risk of WNV transmission.
Proactive measures include eliminating standing water, which serves as breeding grounds for mosquitoes. Residents are urged to dump any water at least once a week. Homeowners can request free mosquito control services from the District for persistent mosquito issues. To bolster the District's surveillance, residents are encouraged to report dead birds—another WNV signal—via phone at (877) WNV-BIRD (968-2473) or through an online platform.
In addition to these preventative actions, using EPA-registered insect repellents containing DEET, Picaridin, Oil of Lemon Eucalyptus, or IR3535 is recommended, with instructions on the repellent labels to be followed closely. Before the peak mosquito season hits, these steps could help curb the spread of WNV among birds, mosquitoes, and humans. More information on mosquito service requests, repellent recommendations, and dead bird reporting can be found on the District's website.
