CONTRA COSTA COUNTY, CA (Sept. 2, 2023) — The Contra Costa Mosquito and Vector Control District (District) reports 11 more dead birds and three more groups of trapped mosquitoes have tested positive for West Nile virus (WNV). The dead birds were collected from Concord (5), Walnut Creek (2), Martinez, Pleasant Hill, El Cerrito, and Alamo. The District trapped the mosquitoes in Discovery Bay, Martinez, and Holland Tract near Knightsen. So far this year, 22 dead birds, 11 groups of trapped mosquitoes, and three sentinel chickens have tested positive for WNV in 2023.
As a result of the elevated WNV activity in Concord, where a total of seven dead birds have tested positive for WNV, the District is conducting additional surveillance and evaluating the possibility of conducting an Adult Mosquito Control operation in the area where the infected dead birds have been collected. The District advises residents to take steps to reduce the risk of mosquito bites over the holiday weekend.
“The combination of an active West Nile virus season and Labor Day weekend keeps District employees busy and it is important that Contra Costa County residents take action to reduce the risk of mosquitoes and mosquito bites. Be sure to wear repellent when outside to reduce the risk of mosquito bites over the holiday weekend. County residents can also deny mosquitoes a place to lay their eggs and develop from egg to adult by dumping out any standing water and scrubbing the inside of the container,” said the District’s Scientific Program Manager Steve Schutz, Ph.D.
The District recommends residents use an EPA-registered insect repellent. It should include one of the four most effective active ingredients. Look for DEET, Picaridin, IR3535, or the repellent version of Oil of Lemon Eucalyptus.
In addition to dumping out standing water and scrubbing the inside of the container to remove mosquito eggs, the District also advises Contra Costa County residents to:
- Make sure door and window screens function in good working condition
- Report dead birds to the California West Nile Virus Dead Bird Call Center
- Report neglected swimming pools to the District. Contra Costa County residents may report a neglected swimming pool anonymously.
- Contact the District to request mosquito service
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 their residential properties by calling (925) 685-9301 or online.
Since 2005, 76 people in Contra Costa County have received a West Nile virus diagnosis. In 2006, two people died from the disease. For human case information, please visit the California Department of Public Health Vector-Borne Disease Section online.
Contra Costa Mosquito & Vector Control District, an independent special district and public health agency, headquarters at 155 Mason Circle in Concord.