West Nile virus risk in Contra Costa County continues as more birds and sentinel chickens test positive

From The Press
September 19, 2020

The Contra Costa Mosquito & Vector Control District (District) has confirmed two sentinel chickens and three dead birds have tested positive for West Nile Virus (WNV).

Two birds are from Brentwood, one is from Concord. This is the first bird from Concord to test positive for WNV this year. Both chickens are from Holland Tract in East Contra Costa County. These are the first sentinel chickens of the year to test positive for WNV in Contra Costa County.

Certain types of birds may carry WNV. When a mosquito bites an infected bird, the mosquito can become infected and transmit the virus to another bird or a person through a mosquito bite.

Chickens serve as sentinels of WNV transmission in a particular area because when an infected mosquito bites a chicken, the chicken is naturally resistant to WNV and does not get sick. Chickens do, however, develop antibodies that can be detected in lab tests and confirm when they have been exposed to WNV. Due to their antibodies, chickens are an important tool in the District’s Integrated Vector Management (IVM) approach to reducing the risk of WNV.

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