Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2011
Year To Date (Weeks 1 - 53)

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

CountyReported*TestedPositive% Tested Positive
Alameda26049--
Alpine----
Amador18---
Butte22255--
Calaveras201--
Colusa175--
Contra Costa1059793848%
Del Norte1---
El Dorado1243027%
Fresno334521529%
Glenn2313215%
Humboldt175--
Imperial1---
Inyo241--
Kern2745547%
Kings6719947%
Lake205120%
Lassen131--
Los Angeles198344022752%
Madera6214321%
Marin60---
Mariposa4---
Mendocino154--
Merced17825936%
Modoc11--
Mono71--
Monterey429--
Napa271--
Nevada571716%
Orange5221985025%
Placer225501020%
Plumas13---
Riverside20833721%
Sacramento124447013429%
San Benito154--
San Bernardino4351123329%
San Diego194103--
San Francisco351--
San Joaquin374732737%
San Luis Obispo8516--
San Mateo17622--
Santa Barbara7311--
Santa Clara6751853519%
Santa Cruz725--
Shasta10943--
Sierra----
Siskiyou3---
Solano1437114%
Sonoma120---
Stanislaus379682435%
Sutter338225%
Tehama509111%
Trinity3---
Tulare334804253%
Tuolumne143--
Ventura1783813%
Yolo17567913%
Yuba3811100%
State Totals10855248968828%

* 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