The Placer Mosquito and Vector Control District confirmed the first mosquito sample to test positive for West Nile virus in the county for the 2021 season. The mosquitoes were collected in a mosquito trap in western Placer County near the Westpark neighborhood of Roseville. Residents are encouraged to use an EPA-registered repellent and dump and drain standing water on their property.

Indicators Placer County* CA*
Human Cases/Fatal Cases 2/0 62/4
Dead Birds 5 198
Mosquito Samples 63 2,191
Horses 0 12
*Placer County results as of 10/4/21; CA results as of 10/1/21.