Invasive Aedes aegypti in San Mateo County

Invasive Aedes mosquitoes are not native to San Mateo County, California, or even North America. They do not belong in our ecosystems, and they can make people very uncomfortable because they bite during the day and even bite indoors. More importantly, they are a risk to human health because they can carry diseases that make people very sick, like Zika, chikungunya, dengue, and yellow fever.

Species of invasive Aedes mosquitoes are found in some areas of Arizona and California. One species, Aedes aegypti, has been found in San Mateo County before. This interactive map by the California Department of Public Health shows where they are currently found in our state.

The District has been working hard to get rid of invasive Aedes mosquitoes in our county, and has been very successful so far. The most recent time any invasive Aedes aegypti mosquitoes were found in San Mateo County was in May of 2015.

Although it has been more than a year since invasive Aedes mosquitoes have been seen in our county, there is a high risk that they will be brought into our county again. The District continues to conduct intensive surveillance throughout the county, but you can help out by reporting suspected invasive Aedes mosquito sightings.