Upcoming West Nile Virus Season

West Nile virus season begins in California in mid-April. The District protects residents from this mosquito-borne disease with control that targets mosquitoes in the larval stage, mosquito population monitoring, disease surveillance and public education. The laboratory staff is prepared to conduct disease surveillance in three main ways:

  • Sentinel Chickens

The District will manage two sentinel chicken flocks of seven chickens each this season, in the cities East Palo Alto and San Mateo. These chickens will be transferred from a farm to their District coops the first week of April. Chicken blood will be tested every two weeks for West Nile virus, Saint Louis encephalitis and Western Equine encephalitis beginning April 16. 

  • 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 or pigeons. Squirrels will not be tested this season. Residents are encouraged to call the state hotline phone number 1-877-WNV-BIRD (1-877- 968-2473), which opens with live operators on April 16. Online reports can be made at

  • Mosquito-borne Disease Testing

The District laboratory submitted and passed proficiency panels supplied by 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.