Aedes aegypti mosquitoes are not native to San Mateo County, so the District’s goal is to completely eradicate them from our county. This is a difficult task, but to date the District has been able to keep the Aedes aegypti population very small and prevent these mosquitoes from spreading beyond the site of their initial introduction in Menlo Park.

The District’s West Nile virus surveillance program reports several types of positive West Nile virus results, including dead birds, mosquito samples (“pools”), sentinel chickens, and human cases.