Areas where invasive Aedes aegypti mosquitoes have been found in San Mateo County.

 

July 2026

• Initial detection of invasive Aedes aegypti adult mosquitoes in a very small area of the Friendly Acres neighborhood in Redwood City in late July.
• As of early August, District staff have visited and checked over 250 properties in the neighborhood. There have been no additional detections of any invasive Aedes aegypti in any water sources or traps.
• District staff will continue visiting this area frequently over the coming months. We are grateful for the continued cooperation of many helpful residents who allowed us access to check their properties. Residents providing access to their properties has played an important part in our ability to determine whether these mosquitoes have spread beyond the initial detection area.
• The public should continue to report biting mosquitoes so that our staff can follow-up.

 

 

Page last reviewed: August 10, 2026