Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2022
Year To Date (Weeks 1 - 49)

(2022-12-09) - Source: http://westnile.ca.gov

CountyReported*TestedPositive% Tested Positive
Alameda22116--
Alpine----
Amador6---
Butte387229%
Calaveras3---
Colusa4---
Contra Costa3623813%
Del Norte----
El Dorado279--
Fresno1237229%
Glenn4---
Humboldt51--
Imperial----
Inyo----
Kern22---
Kings10---
Lake125240%
Lassen1---
Los Angeles7711134742%
Madera83267%
Marin554--
Mariposa----
Mendocino5---
Merced446117%
Modoc----
Mono----
Monterey174--
Napa199--
Nevada113133%
Orange39027910%
Placer9047511%
Plumas3---
Riverside8921524%
Sacramento6042694015%
San Benito3---
San Bernardino10124729%
San Diego11842--
San Francisco428--
San Joaquin1232913%
San Luis Obispo152--
San Mateo24659--
Santa Barbara244--
Santa Clara456812632%
Santa Cruz5410--
Shasta275120%
Sierra----
Siskiyou1---
Solano14033927%
Sonoma951915%
Stanislaus1195--
Sutter4213431%
Tehama5---
Trinity----
Tulare337229%
Tuolumne3---
Ventura6610110%
Yolo171732433%
Yuba2810110%
State Totals4856127518615%

* 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