CONCORD, CALIFORNIA - 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) in Contra Costa County. The dead birds were collected from Concord (5), Walnut Creek (2), Martinez, Pleasant Hill, El Cerrito, and Alamo; while the mosquitoes were trapped in Discovery Bay, Martinez, and Holland Tract near Knightsen. So far this year, there have been 22 dead birds, 11 groups of trapped mosquitoes, and three sentinel chickens that 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 also advises Contra Costa County residents to take the necessary steps to reduce the risk of mosquitoes and mosquito bites over the holiday weekend.