The District has discovered the invasive mosquito species Aedes aegypti in Contra Costa County.  The mosquitoes were found in Martinez, south of Highway 4.  We are conducting door-to-door surveillance and treatment in the area where these mosquitoes were identified to limit the presence of these invasive mosquitoes because they have the ability to transmit the causative agents of Dengue, Zika, Chikungunya, and Yellow fever. Learn More.


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Frequently Asked Questions

Get all the answers to our most frequently asked questions.

Invasive Mosquito Species of California

One of the two species that can transmit Zika, dengue, yellow fever, and chikungunya, was found in Contra Costa County in August, 2022.

95 Years of Protecting Public Health

The District is celebrating a milestone as a public health agency.