Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2021
Year To Date (Weeks 1 - 30)

(2021-08-04) - Source: http://westnile.ca.gov

CountyReported*TestedPositive% Tested Positive
Alameda1881--
Alpine----
Amador4---
Butte206--
Calaveras4---
Colusa1---
Contra Costa23722--
Del Norte1---
El Dorado326--
Fresno587--
Glenn3---
Humboldt1---
Imperial1---
Inyo1---
Kern194--
Kings9---
Lake42--
Lassen----
Los Angeles455711623%
Madera62--
Marin272--
Mariposa----
Mendocino3---
Merced222150%
Modoc----
Mono----
Monterey97--
Napa166--
Nevada132--
Orange318249--
Placer782628%
Plumas----
Riverside7515--
Sacramento5142906623%
San Benito3---
San Bernardino801417%
San Diego9146--
San Francisco182--
San Joaquin98411229%
San Luis Obispo152--
San Mateo20559--
Santa Barbara266--
Santa Clara34156--
Santa Cruz5013--
Shasta18---
Sierra----
Siskiyou1---
Solano4212--
Sonoma837114%
Stanislaus929111%
Sutter163--
Tehama2---
Trinity1---
Tulare3611545%
Tuolumne----
Ventura316--
Yolo10842--
Yuba153--
State Totals3491105210510%

* 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