Why It’s So Important to Prevent the Invasive Ades Aegypti Mosquito

Contra Costa Mosquito and Vector Control District

by CC News 07/31/2025

written by CC News 07/31/2025

The Contra Costa Mosquito and Vector Control District (District) has been working to control Aedes aegypti, commonly known as the Yellow Fever mosquito, in Antioch, where the District found this non-native mosquito in late 2024 and again this year. The District previously found this mosquito in Martinez in 2022; however, after the District’s eradication efforts, with the help of the residents, no more of these dangerous mosquitoes have been found in Martinez.

It is dangerous because:

This mosquito can transmit the viruses that cause Yellow fever, as well as Zika, Dengue fever, and Chikungunya.

It is hard to detect and control because:

This mosquito is very small, just 1/8 – 1/4 inch, and can bite a person without the person even knowing they were bitten.
This mosquito prefers to bite people and bites throughout the day, indoors or outdoors.
This mosquito lays its eggs just above the water line. The eggs are very resilient and can still develop into adult mosquitoes if they are exposed to water after six months

So, what can you do to prevent Aedes aegypti mosquitoes on your property?

The most important thing you can do is to dump out any amount of standing water in your front and backyard at least once a week.

The places to look for even small amounts of standing water include:

Plant saucers
Buckets
Bird baths
Rain barrels
Septic tanks
Tires
Toys
Pet bowls
Wheelbarrows
Outdoor vases
Treeholes
Certain plants where a plant leaf meets the stem

If, after dumping out any amount of standing water you find on your property, you still notice mosquitoes, contact the District immediately and request Mosquito service. A District employee will check the property for signs of mosquitoes and may set a mosquito trap to find what species of mosquitoes may be on the property and from where they may be coming.

In addition to responding to residents’ requests for service to prevent Aedes aegypti, District employees are also going door-to-door to check front and backyards to stop this mosquito before it becomes more widespread.

The bottom line is, if this mosquito becomes established in Contra Costa County, it has the potential to change our way of life because not only is it an aggressive biter, it can transmit dangerous viruses to you, your family, and your neighbors.

Contra Costa Mosquito and Vector Control District, an independent special district and public health agency, is temporarily located at 5750 Imhoff Road, Suite I, Concord, CA 94520. Contact the District to report mosquito and vector problems online or at (925) 685-9301.

Previous