Aedes aegypti FAQs
Aedes aegypti, also known as the yellow fever mosquito, is an invasive species native to Africa and is highly adaptive to its environment. In California, it was first discovered in 2013 in Fresno, Madera, and San Mateo counties. Aedes aegypti is now found in at least 26 counties statewide, including nearby counties.
Aedes aegypti mosquitoes can transmit diseases, such as dengue, Zika, chikungunya and yellow fever. If Aedes aegypti becomes established in Alameda County, it could threaten public health and quality of life, as these mosquitoes are highly aggressive and active during daylight hours.
Aedes aegypti Detections and Detection Zones in Alameda County
The Alameda County Mosquito Abatement District performs year-round mosquito surveillance and control activities throughout Alameda County.
As of October 2025, the District has found numerous adults and larval Aedes aegypti mosquitoes in Livermore, Pleasanton, and Fremont. Residents can expect to see District staff conduct:
- Surveillance trapping
- Mosquito control and/or
- Door-to-door inspections where we check for standing water sources
Mosquitoes need water for their life cycle. They lay eggs near water and swim in water for their larval stage and pupa stage. Without standing water, mosquito eggs will not hatch, this is why we inspect for standing water.
Door-to-door Inspections – What to Expect
Door-to-door inspections consist of staff looking for any mosquito eggs, larvae, or pupa in standing water that can serve as a mosquito breeding habitat. Aedes aegypti mosquitoes are “container” breeders, meaning that female adults lay their eggs on the sides of containers like buckets, pot saucers, lawn drains, and other artificial containers and yard clutter that can hold a bottlecap or more of water. Dry eggs can also survive from months to years after being laid and hatch into larvae once re-introduced to water. Staff can also provide treatment (free of charge) for any standing water sources that cannot be covered or drained.
Staff will always wear their District uniform with official logos and identification. Additionally, residents can expect to see District employees use District vehicles with the official logo.
KRON 4 did a segment on a detection in Livermore and provides examples of what residents can expect to see during an inspection.
KRON 4 news segment from August 12, 2025
Protect Yourself from Mosquito Bites:
- Apply insect repellents containing EPA-registered ingredients such as DEET, picaridin, IR3535, or oil of lemon eucalyptus.
- Wear long-sleeved shirts, pants, socks, and shoes when mosquitoes are most active.
- Ensure window and door screens are in good condition.
- Dump out any standing water – even as little as a bottlecap!
- Scrub items that were holding water with dish soap or a 5% bleach solution.
- Cover openings of sumps, water collection containers, and lawn drains with window screen or a finer mesh material.
- Report daytime mosquito activity immediately to the Alameda County Mosquito Abatement District at (510) 783-7744 or www.mosquitoes.org.
If you develop a fever, headache, and joint or muscle pain after returning from an area where dengue, chikungunya, yellow fever, or Zika is present, contact your doctor. Use mosquito repellent for three weeks and stay indoors as much as possible to avoid mosquito bites and prevent the possible spread of disease.
For additional information about Aedes aegypti