Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2008
Year To Date (Weeks 1 - 53)

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

CountyReported*TestedPositive% Tested Positive
Alameda706128129%
Alpine3---
Amador11025312%
Butte7511393827%
Calaveras1292814%
Colusa467343%
Contra Costa22273218827%
Del Norte272150%
El Dorado54389910%
Fresno12321754425%
Glenn92371746%
Humboldt786117%
Imperial35---
Inyo357--
Kern1590193105%
Kings13310110%
Lake9411218%
Lassen233--
Los Angeles553592448152%
Madera12130310%
Marin2192814%
Mariposa184--
Mendocino791616%
Merced20732516%
Modoc172150%
Mono113267%
Monterey27244614%
Napa883133%
Nevada3055958%
Orange299695663266%
Placer72418422%
Plumas5716--
Riverside1269903943%
Sacramento310642013031%
San Benito345--
San Bernardino155432717654%
San Diego174283256668%
San Francisco10514--
San Joaquin15092026934%
San Luis Obispo1802927%
San Mateo3897323%
Santa Barbara961616%
Santa Clara961931314%
Santa Cruz16330310%
Shasta40620735%
Sierra161--
Siskiyou213--
Solano54220735%
Sonoma495931112%
Stanislaus9381284535%
Sutter1798225%
Tehama13731619%
Trinity143133%
Tulare7541827642%
Tuolumne928--
Ventura5531022424%
Yolo53460915%
Yuba1038--
State Totals343956114256142%

* 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