Dead Birds Reported, Tested, and Positive
for WNV by County in California in 2022
Year To Date (Weeks 1 - 53)

(2024-06-18) - Source: http://westnile.ca.gov

CountyReported*TestedPositive% Tested Positive
Alameda23038--
Alpine----
Amador6---
Butte387229%
Calaveras3---
Colusa4---
Contra Costa3734212%
Del Norte----
El Dorado279--
Fresno1248225%
Glenn4---
Humboldt51--
Imperial----
Inyo----
Kern231--
Kings11---
Lake126233%
Lassen1---
Los Angeles7831154943%
Madera83267%
Marin564--
Mariposa----
Mendocino5---
Merced447229%
Modoc----
Mono----
Monterey184--
Napa209--
Nevada114125%
Orange41128410%
Placer9347511%
Plumas3---
Riverside9321524%
Sacramento6172704015%
San Benito3---
San Bernardino10124729%
San Diego12747--
San Francisco448--
San Joaquin1242913%
San Luis Obispo162--
San Mateo26264--
Santa Barbara255--
Santa Clara4631042625%
Santa Cruz5710--
Shasta286117%
Sierra----
Siskiyou1---
Solano14333927%
Sonoma981915%
Stanislaus1215--
Sutter4713431%
Tehama5---
Trinity----
Tulare339222%
Tuolumne3---
Ventura6710110%
Yolo177732433%
Yuba2810110%
State Totals4996135118914%

* 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