Adult Mosquito Surveillance 

The District maintains a multifaceted surveillance program for arboviruses, including West Nile virus (WNV), St. Louis encephalitis virus (SLEV), and western equine encephalitis virus (WEEV). Using both active (mosquito trapping) and passive (bird and human disease reports) monitoring techniques, the District detects and quantifies the intensity of virus transmission in the region. With this information, the District can predict areas and times of elevated disease risk and direct critical vector control interventions to effectively protect human health.

Below are the different types of adult mosquito surveillance traps used by the District:

Gravid Trap: Gravid traps use nutrient rich water to attract female mosquitoes that are looking to lay eggs.

BG Sentinel Trap: BG traps use both CO2 and a scented lure to attract adult mosquitoes

Encephalitis Vector Survey Trap: These traps use CO2 and light to attract adult mosquitoes.

Autocidal Gavid Ovitrap: This trap is deployed to detect invasive Aedes adult mosquitoes that are looking for a place to lay their eggs.

Larval Mosquito Surveillance

In addition to our adult mosquito surveillance program, our vector control technicians conduct daily larval surveillance to monitor mosquito density and diversity. This is done by inspecting over 20,000 known sources of mosquito production in both Marin and Sonoma counties. These areas are checked on a regular basis and treated when necessary. They include but are not limited to ditches, catch basins, backyard ponds and creeks.