West Nile Virus Lethally Detected in Contra Costa County for the First Time in 2023
In the East Bay region of California, the West Nile virus (WNV) has made its presence known this year. Contra Costa County reported its first WNV-positive bird, a California scrub jay in San Ramon, on July 21, marking the beginning of local virus activity [3][5]. Alameda County has recorded at least five WNV-positive dead birds, including one in Castro Valley, leading the Bay Area in detections [1]. Santa Clara County has also reported infected birds, indicating a regional increase in WNV presence.
On August 1, 2025, Contra Costa County found its first WNV-infected mosquitoes, further confirming active transmission in the area [1][3][5]. Health officials warn that as temperatures rise, the risk of human cases will likely increase. They emphasize preventive measures such as eliminating standing water to reduce mosquito breeding, using EPA-registered insect repellents, and reporting dead birds to local mosquito control authorities.
Most people bitten by an infected mosquito never feel sick, but about 1 in 5 develop fever, headache, or body aches. Roughly 1 in 150 experience severe neurological complications such as meningitis or encephalitis, which can be fatal. Older adults and those with weakened immune systems are at greatest risk for severe complications from West Nile virus.
Vector-control crews are increasing surveillance and larval-source reduction in the San Ramon area and other East Bay hot spots. The 925 News newsletter, built with Kit, keeps readers updated on the developing West Nile virus story, including potential human cases [2]. Related articles on the 925 News website include "First West Nile Virus Death Since 2006 Reported in Contra Costa County," "A New Mosquito Was Found in Pleasanton, and It's Very Bad News," and "Contra Costa Gets $1.5 Million to Fight Climate Change."
The newsletter also covers local news, events, restaurant openings, small business spotlights, and crime reports in Walnut Creek, Lamorinda, Danville, Concord, and the Trivalley. Sharing options for the newsletter are available on Facebook, Pinterest, and Nextdoor. Residents are urged to stay vigilant through late fall, when cooler weather typically suppresses the West Nile virus.
[1] Contra Costa Times, "Contra Costa County finds first West Nile virus-infected mosquitoes," August 1, 2025. [2] 925 News, "West Nile Virus Activity Detected in East Bay Region of California," August 3, 2025. [3] ABC7 News, "First West Nile virus-positive bird of 2025 found in Contra Costa County," July 22, 2025. [4] KCRA, "California scrub jay in San Ramon tests positive for West Nile virus," July 22, 2025. [5] San Francisco Chronicle, "State surveillance data show Alameda leads Bay Area in West Nile virus detections," August 5, 2025.
- Science and healthcare professionals are closely monitoring the spread of the West Nile virus in the East Bay region of California.
- Chronic diseases like chronic kidney disease, cancer, and neurological disorders are not directly related to the West Nile virus, but general health-and-wellness practices, including fitness-and-exercise, mental-health care, nutrition, skin-care, and eye-health maintenance, are crucial for overall well-being.
- Respiratory conditions may not be an immediate concern with the West Nile virus, but it's essential to be aware of any symptoms related to the virus or other health issues.
- Hearing impairment is unrelated to the West Nile virus, but maintaining regular health check-ups can help detect any potential issues early.
- As the West Nile virus poses a risk, staying updated on medical-conditions, including its symptoms, preventions, and treatment, is crucial.
- While West Nile viruscare is important, it's also essential to recognize lesser-known conditions like skin-conditions and cardiovascular-health issues, which can significantly impact one's quality of life.
- In addition to West Nile virus concerns, local news outlets like 925 News also cover various topics such as community events, restaurant openings, and crime reports.
- Public health officials remind everyone to adopt preventive measures against mosquito bites, as the risk of West Nile virus transmission increases with warmer temperatures, and to stay vigilant until cooler weather typically suppresses the virus activity.
