"It's Here." Aedes aegypti in Alameda County

This fall our office has been extremely busy with multiple Aedes aegypti detections, primarily in Livermore, but we also found the invasive mosquitoes in Dublin, Pleasanton and Fremont. After our detections in 2024 in Pleasanton, the District completed an internal assessment of how we addressed Aedes aegypti and what we needed to do to prepare for future invasive Aedes concerns. We learned a few things along the way, including that neighborhoods where neighbors talk to one another are easier to inspect, school districts are great at getting the attention of families, and people can accidentally spread Aedes eggs when they propagate plants. When we reflect on what we learned, we realized that many of our goals to prepare for Aedes aegypti were already in our 2024-2026 strategic plan. 

Changes we have made in 2025 include:

• Hired Lizbeth Martinez, to the newly created role of Community Liaison, who leads our invasive Aedes response 
• Held the first Invasive Aedes Regional Summit with multiple nearby mosquito abatement agencies
• Developed a new monitoring tool using PCR testing on suspected areas of mosquito breeding: Barcoding Quantitative PCR Assay to Distinguish Between Aedes aegypti and Aedes sierrensis
• Started a new partnership with UC Master Gardeners which enables the group to disseminate information to over 50 farmers markets in Alameda County: UC Master Gardener Program of Alameda County
• Deployed a multilingual AI bot, Ally that can answer questions about Aedes aegypti on phone calls and on the mosquitoes.org website 
• Enhanced Aedes aegypti information on website: Aedes aegypti FAQs 
• Modified classroom lessons to incorporate Aedes aegypti information
• Revised fogging notifications to include preventative larval treatments WALS in residential areas: Stay in touch

As we look into the future we recognize there will be more detections and more locations. We will continue to control all species of mosquitoes by focusing on catching mosquitoes during their larval stage. We will also continue to learn about new methods of control for aggressive daytime-biting Aedes aegypti. To keep Aedes aegypti in check we will need community support and engagement along with residents doing their part to remove or treat standing water. 

Top left: Regulatory and Public Affairs Director Erika confirms the mosquito found in a trap is an Aedes aegypti mosquito. Top right: Community Liasion Liz speaks to the Pleasanton-Livermore CERT group about Aedes aegypti and the common locations they hide their eggs. Bottom left: Mosquito Control Technician Danny speaks to Dublin residents about common areas of standing water, particularly plant saucers. Bottom right: Lab Director Eric speaks with a reporter from KRON4 about the Aedes aegypti response and the traps we use to monitor for mosquitoes. 

Events and Outreach

Our office has been busy spreading the word about mosquito prevention. This season we have been to new events and old favorites. Take a look at a few of them!

Top left: Public Education Officer Judith, Vector Biologist Erick, Newark Trustee Eric and Vice Mayor of Newark Eve attend the "Celebrate Heros" tablinig event in early October. Top right: Mosquito Control Technician Danny and Assistant Vector Scientist Eric attend the Livermore Resource and Volunteer Fair in August, A Master Gardener looking through the microscope to see the identifying features of Aedes aegypti. Seasonal Technician Christian, Vector Biologist Sarah and Hayward Trustee and Councilman George attend the Downtown Hayward 3rd Thursday Street Party. Eric shows mosquito samples to Dublin residents at the first Friday Night Market in September. 

DIY tips to reduce mosquitoes 

Residents who want to decrease their risk for mosquitoes on their properties have many items they can look for, from toys to tarps, there are many items that can hold enough water to produce mosquitoes. Review the list to find out where water may be hiding on your property. And thank you to Greater Los Angeles County Vector Control District for allowing our team to adapt their list.  DIY Mosquito Prevention Tips

West Nile Virus update

In the Bay Area, we’ve seen very low West Nile virus activity among birds, mosquitoes, and humans this year. In total, only six West Nile virus–positive birds have been found in Alameda County. Contra Costa County and Santa Clara County are also reporting low numbers. However, West Nile virus activity has been increasing in the Central Valley, particularly around Visalia.

If you’re traveling to areas with higher West Nile virus activity, remember to limit outdoor exposure, wear long sleeves and pants, and use mosquito repellent.

West Nile virus is endemic in California—it often recedes and then flares up again. Residents are encouraged to keep their homes protected from mosquitoes by maintaining window and door screens in good condition and by inspecting for standing water, including areas such as sump pumps.