Aedes aegypti Surveillance


How to Interpret Aedes aegypti Surveillance Data

Aedes aegypti mosquitoes are not native to San Mateo County, so the District’s goal is to completely eradicate them from our county. This is a difficult task, but to date the District has been able to keep the Aedes aegypti population very small and prevent these mosquitoes from spreading beyond the site of their initial introduction in Menlo Park.

A detection (as designated by a colored star on the Aedes aegypti maps below) means that one or more Aedes aegypti adults, larvae, or eggs was found at that site. The accompanying tables describe what was found at each detection - eggs, larvae, or adults.

The year-to-date surveillance report describes the number of each type of trap used and the number and species of mosquito collected in each trap. For more information about the traps used to detect Aedes aegypti, see Finding Aedes aegypti Mosquitoes.


Invasive Aedes surveillance in summer 2020

The District conducts intensive surveillance for invasive Aedes mosquitoes during the summer months. The surveillance program mainly targets two container-breeding species, Aedes aegypti and Aedes albopictus, which have been increasing their range within California over the last several years. This summer, Ae. aegypti and Ae. albopictus were detected for the first time in Shasta County. The presence of these mosquitoes is highly undesirable because they are aggressive human biters and also transmit diseases including dengue, chikungunya, yellow fever and Zika.


2018 Invasive Aedes Surveillance

The seasonal invasive Aedes surveillance primarily targets the detection of two mosquito species that have been expanding their range in California, Aedes aegypti, and Aedes albopictus. The presence of these mosquitoes is highly undesirable because they are aggressive human biters and also transmit diseases including dengue, chikungunya, yellow fever and Zika.  From 2013-2015, the District supressed Ae. aegypti in a small area of Menlo Park, but no invasive Aedes have been detected since August 2015.


Invasive Aedes Update for San Mateo County
February 2018

To date, no invasive Aedes mosquitoes have been detected in San Mateo County since 2015.

See an interactive map of invasive Aedes detections in California.


Latest Aedes aegypti Detections in San Mateo County
Updated Sept. 9, 2016

Note: as of Sept. 9, 2016, there have been no additional invasive Aedes detections since May 2015.

The map below shows the location of each detection of invasive Aedes aegypti mosquitoes in San Mateo County. So far, Aedes aegypti has been detected eight times in 2015, all in the neighborhood of Menlo Park where it was found last year.

Each of these detections has been in the aquatic stages; so far no adult Aedes aegypti mosquitoes have been found in San Mateo County in 2015.


Aedes aegypti Year-to-Date Surveillance Program

The file below contains the results of the Aedes aegypti surveillance program in 2015 to date.


Aedes aegypti Surveillance Locations
Ovicup traps

This map (click for larger version) shows the location of the 30 ovicup mosquito surveillance traps placed in Menlo Park. These traps are used to monitor for the presence of Aedes aegypti and other invasive mosquito species.


Aedes aegypti in San Mateo County 2013-2015
Updated April 8, 2015

To date, District laboratory staff have identified four samples of immature Aedes aegypti mosquitoes collected in Menlo Park. The samples were collected near the site of previous years’ detections.

To see a map of all Aedes aegypti detections since 2013, click the file below.