Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2020
Year To Date (Weeks 1 - 39)

(2020-09-27) - Source: http://westnile.ca.gov

CountyReported*TestedPositive% Tested Positive
Alameda2942528%
Alpine2---
Amador4---
Butte439333%
Calaveras1---
Colusa1---
Contra Costa359521733%
Del Norte----
El Dorado2812--
Fresno16515533%
Glenn1---
Humboldt72--
Imperial----
Inyo----
Kern9---
Kings9---
Lake76--
Lassen----
Los Angeles6831526643%
Madera13---
Marin203133%
Mariposa----
Mendocino1---
Merced585240%
Modoc----
Mono1---
Monterey184--
Napa113133%
Nevada15---
Orange4281623823%
Placer1085124%
Plumas2---
Riverside1342528%
Sacramento6122968127%
San Benito1---
San Bernardino6010--
San Diego16093--
San Francisco294--
San Joaquin13535411%
San Luis Obispo142--
San Mateo15046--
Santa Barbara101--
Santa Clara39912654%
Santa Cruz6114--
Shasta17---
Sierra----
Siskiyou----
Solano562115%
Sonoma487--
Stanislaus16312433%
Sutter318--
Tehama3---
Trinity----
Tulare4810330%
Tuolumne11--
Ventura4815--
Yolo150732433%
Yuba201--
State Totals4638130126120%

* 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