Sentinel Chickens
2017 Flocks have arrived!

The 2017 sentinel chickens are situated in their coops for the West Nile Virus season. The three coops are at Woodside, East Palo Alto and San Mateo and contain ten chickens each. Starting May 1, the chickens will be tested every two weeks for the mosquito-borne diseases West Nile Virus, Saint Louis Encephalitis, and Western Equine Encephalitis.

Sentinel chickens are an important part of our program because they can be an early indicator that a mosquito-borne disease is in the area.  The mosquitoes that vector West Nile Virus, of the genus Culex, prefer to bite birds. If a chicken is infected by a mosquito, it does not develop disease symptoms but antibodies to the virus develop in their blood which can be detected with a blood test. Chickens typically don’t develop a high enough level of virus to infect other mosquitoes that bite them so they can’t amplify the virus after infection.  For these reasons, they are considered excellent sentinels.

Other early West Nile Virus surveillance conducted by the District is dead bird testing.  The California West Nile Virus dead bird hotline will start taking live telephone calls starting April 17.  Residents who notice dead birds are encouraged to call 1-877-WNV-BIRD or make an online report at