Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2010
Year To Date (Weeks 1 - 53)

(2021-12-01) - Source: http://westnile.ca.gov

CountyReported*TestedPositive% Tested Positive
Alameda3106212%
Alpine----
Amador20---
Butte37710266%
Calaveras354--
Colusa201417%
Contra Costa92432825%
Del Norte----
El Dorado1854425%
Fresno427652234%
Glenn2014321%
Humboldt71--
Imperial6---
Inyo142--
Kern248431330%
Kings452--
Lake7411--
Lassen92--
Los Angeles13082514116%
Madera73191368%
Marin75---
Mariposa7---
Mendocino193--
Merced257461430%
Modoc145--
Mono122150%
Monterey11117--
Napa22---
Nevada5310--
Orange495204178%
Placer28071913%
Plumas53--
Riverside2435120%
Sacramento132032111536%
San Benito264--
San Bernardino5181041010%
San Diego24211122%
San Francisco496--
San Joaquin502922628%
San Luis Obispo7713--
San Mateo16527--
Santa Barbara5114--
Santa Clara8421273225%
Santa Cruz7622418%
Shasta12735411%
Sierra1---
Siskiyou8---
Solano1372150%
Sonoma143---
Stanislaus355853440%
Sutter404125%
Tehama449--
Trinity5---
Tulare218432149%
Tuolumne192--
Ventura16637--
Yolo211431433%
Yuba371--
State Totals11074213641619%

* Birds in a die-off are not included in reported totals because the deaths are not related to WNV. A die-off is defined as a group of 10 or more same species dead birds unless the species is American Crow.
Source: Vector-Borne Disease Section, California Department of Public Health