More West Nile Virus-infected dead birds confirmed in Contra Costa County

CONTRA COSTA COUNTY, CA (June 23, 2024) — The Contra Costa Mosquito and Vector Control District (District) reports two more dead birds have tested positive for West Nile virus (WNV) in Contra Costa County. The dead birds, both American crows, were picked up in an area of Concord on June 17, 2024. These WNV-positive birds follow the first bird reported from Contra Costa County this year in April. WNV-infected dead birds have also been reported from Alameda, San Mateo, and Santa Clara Counties.

“Certain birds carry West Nile virus. When we receive a report of a dead bird in a particular area, we set mosquito traps in that area to determine if any infected mosquitoes are present. Now that it’s summer, with increasing temperatures, the risk of West Nile virus increases, because the virus reaches higher levels in mosquitoes when the outside temperature stays above 55 degrees at night,” said Steve Schutz, Ph.D., Scientific Program Director. “This is the time of year when it’s very important for Contra Costa County residents to take precautions to reduce the risk of mosquito bites and to report dead birds because dead birds are often the first sign of WNV in a particular location.”

To reduce the risk of mosquitoes and WNV, the District recommends residents look around their yards at least once a week. Scrub anything holding water, then dump that water out. Scrubbing the inside of each container dislodges mosquito eggs that stuck to the container. Also, make sure window screens properly fit openings without gaps, and there are no rips or tears.

If, after dumping and scrubbing, you still experiences mosquito issues on the property, Contra Costa County residents can contact the District to request mosquito service.

Insect repellent

To reduce the risk of mosquito bites, the District recommends residents use EPA-registered insect repellents with one of the following active ingredients:

• DEET
• Picaridin
• The repellent version of Oil of Lemon Eucalyptus
• IR3535

Always follow the instructions on the label when using insect repellent. Report dead birds because dead birds often provide the first sign of WNV in a particular location.

Contra Costa County residents can report dead birds by phone at (877) WNV-BIRD (968-2473) or online. County residents can also request mosquito service for residential property by calling (925) 685-9301 or online.