Mosquitoes carrying West Nile virus found in parts of Bay Area


Officials have identified adult mosquitoes that tested positive for West Nile virus in some parts of the South Bay.

Santa Clara County Vector Control District said in a press release Friday that infected mosquitoes were detected in Santa Clara and Sunnyvale.

The county will coordinate a mosquito control treatment in zip codes 94086, 94087 and 95051 beginning Monday night at 10 p.m., and will not require residents to relocate, the district said.

Those who want to reduce their exposure to pesticides are encouraged by the county to close their windows and stay indoors for three hours of treatment.


This follows a treatment at the Gilroy party held Thursday evening after mosquitoes were found in the area.

Four counties in the Bay Area – Santa Clara, Contra Costa, Solano and Sonoma – have reported West Nile virus activity, according to an activity map posted by the California Department of Public Health. Only Solano County reports any human infection.

But the first human death from West Nile virus in California in 2021 took place in July, when people in San Luis Obispo County died of complications from the virus.

As always, health authorities recommend that people pour standing water regularly and limit outdoor activities when mosquitoes are most active at dusk and dawn.

The first cases of West Nile virus were reported in California in 2003; since then, 339 people have died from the virus and more than 7,000 have been infected. Most people infected with the virus do not report any disease.

The Vector Control District did not immediately respond to a request for comment from SFGATE.

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