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Current West Nile Virus Information for San Mateo County

2022 Season

West Nile Virus Update

The District collects and tests dead birds reported by residents. Dead birds should be in good condition without signs of decay or trauma. All bird species are accepted except water fowl, poultry and pigeons/doves.

Residents who find a dead bird in good condition should call 1-877-WNV-BIRD (1-877-968-2473) or file a report online at

San Mateo County

To date, West Nile virus (WNV) has not been detected in any dead bird, mosquito or sentinel chicken samples in San Mateo County in 2022. The District has had 170 reports of dead birds, and 42 have been tested for WNV.


Thus far in 2022, WNV has been detected in 26 counties statewide, including three in the coastal region: Santa Clara County, Solano and Contra Costa County. Statewide detections include 2,136 mosquito samples, 78 sentinel chickens, 5 horses and 116 dead birds. This year to date, 3,713 birds have been reported, 993 have been tested and 116 have tested positive for WNV (12%) in California. Additionally, there have been 35 human cases of WNV, including one in the coastal region (Solano County).

May contain: land, nature, outdoors, rainforest, plant, tree, vegetation, and plot


Date last reviewed: September 9,, 2022

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