Vector control officials warn of dengue risk, test sterile-male mosquito program in San Fernando area

The Greater Los Angeles County Vector Control District told the San Fernando City Council the county is seeing increased dengue risk from invasive Aedes aegypti mosquitoes and described a pilot program releasing sterilized male mosquitoes that the district says reduced local mosquito populations.

"We had 140 travel associated cases just in our jurisdiction," General Manager Suzanne Clue told the council, and she reported three locally transmitted dengue cases in the district last year. Clue described an integrated approach of surveillance, resident education and control work focused on both standing and flowing water sources and said the district responds at no additional cost to residents because operations are funded through a property tax assessment.

Clue described a growing program called sterile insect technique (SIT), in which the district sterilizes male Aedes aegypti mosquitoes with radiation and releases them so they mate with wild females and produce nonviable eggs. "Last year's pilot program in Sunland, Tuhanga has shown an 82% reduction of our mosquito population compared to control areas," Clue said. She and councilmembers discussed expanding the program, funding options and the district's community outreach to teach residents how to remove small containers of standing water that breed mosquitoes.

Why it matters: Aedes aegypti is a daytime-biting species capable of transmitting dengue, Zika and other viruses. The district said insecticide resistance and the species' ability to breed in very small containers limits traditional control methods and motivates new approaches such as SIT.

Council response and next steps: Councilmembers asked for more local outreach and for district materials to be shared via city communications. Clue said the district is asking property owners about a potential funding measure to expand SIT across the district and offered to coordinate messaging with the city. The council requested contact information and educational materials for distribution at senior and school events.

Ending: The district said residents should report standing water or dead birds to the district for testing; it offered to work with the city's communications team to share prevention steps and event information.