Current West Nile Virus Information for San Mateo County
2024
A total of 36 dead birds have tested positive for West Nile virus in 2024. The most recent positive bird (late October) was from Atherton.
As of November 13, 2024, a total of 512 dead birds have been reported, of which 150 were in testable condition.
As of November 13, the District has tested over 6,100 mosquitoes. So far in 2024, no mosquito pools have tested positive for West Nile virus in San Mateo County.
This map includes approximate locations of West Nile virus positive samples in 2024. The map is lagged a little, so some of the most recent birds are not yet included on the map.
Learn more about West Nile virus activity throughout California.
| Location | Number of West Nile virus-positive birds in 2024 |
|---|---|
| Atherton | 6 |
| Foster City | 2 |
| Menlo Park | 15 |
| Redwood City | 1 |
| San Carlos | 3 |
| San Mateo | 2 |
| Portola Valley | 1 |
| Unincorporated San Mateo County* | 6 |
*Menlo Oaks (3 birds), North Fair Oaks (2 birds), West Menlo Park (1 bird)
2023
In 2023, no mosquito pools tested positive for West Nile virus in San Mateo County. No sentinel chickens tested positive for West Nile virus. For information about West Nile virus in humans and horses, visit: https://westnile.ca.gov/ or www.cdfa.ca.gov/AHFSS/Animal_Health/Wnv_Info.html
In 2023, a total of 15 dead birds tested positive for West Nile virus in San Mateo County. Positive birds were found in Belmont (1), Burlingame (1), Foster City (1), Redwood City (1 in Redwood City; 3 in Redwood Shores area; 2 on the border of Redwood City and North Fair Oaks), San Carlos (1), and Menlo Park (5). Additional mosquito trapping and testing done in areas where dead birds were found did not found any positive mosquitoes.
Learn how to avoid mosquito bites and select a safe, effective mosquito repellent.
Page last reviewed: November 15, 2024
