Culex mosquitoes are able to carry and spread West Nile virus. Our staff collect mosquitoes from around the County using traps set overnight and baited with carbon dioxide and scent lures. Mosquitoes are grouped into batches called "pools" for testing. They are tested using a triplex PCR test.

The California Department of Public Health (CDPH) West Nile Virus Dead Bird Hotline is an important part of West Nile virus surveillance. Residents who find a dead bird in good condition should file a report online or by calling 1-877-WNV-BIRD (1-877- 968-2473). The District receives reports of dead birds year-round from CDPH and will collect and test suitable birds in any season.

Surveillance for West Nile virus begins in California each year in 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 conduct surveillance to detect the presence of mosquito-borne disease by testing dead birds and trapped…