West Nile Virus Season Begins

Surveillance for West Nile virus began in California in mid-April. The District protects residents from this mosquito-borne disease with control methods that target mosquitoes in the larval stage, as well as mosquito population monitoring, disease surveillance and public education. The laboratory staff conducts disease surveillance in three main ways:

Sentinel Chickens

The District manages two sentinel chicken flocks of seven chickens each, in the cities East Palo Alto and San Mateo. These chickens were transferred from a farm to their District coops the first week of April. Chicken blood is tested every two weeks for West Nile virus, Saint Louis encephalitis and western equine encephalitis from April 22 to November 4.

Dead Bird Surveillance

The District collects dead birds that are 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. Residents are encouraged to call the state hotline phone number 1-877-WNV-BIRD (1-877- 968-2473), which opened with live operators on April 15. Online reports can be made at

Mosquito-borne Disease Testing

The District laboratory submitted and passed proficiency panels supplied by UC Davis Arbovirus Research and Training (DART) for West Nile virus, Saint Louis encephalitis and western equine encephalitis. The proficiency panels ensure that the testing methods and equipment are capable of detecting these three viruses for the upcoming season and will be acceptable for reporting by the California Department of Public Health (CDPH). Our District will test saliva or ocular samples from dead birds and pooled whole mosquitoes for the presence of these viruses.