2026 WNV Activity by County

(2026-11-12) - Source: http://westnile.ca.gov

Total Positive Counties: 39

CountyHuman CasesDead BirdsMosquito SamplesSentinel ChickensHorses
State Totals528786414714917
Alameda-3910--
Alpine-----
Amador----2
Butte1313931-
Calaveras---2-
Colusa--15-
Contra Costa115221
Del Norte-----
El Dorado-1--1
Fresno253144-1
Glenn6-1--
Humboldt-----
Imperial--7--
Inyo-----
Kern10-128--
Kings11-83-1
Lake--53-
Lassen-----
Los Angeles30416582262-
Madera33536--
Marin-----
Mariposa-----
Mendocino-----
Merced3287-1
Modoc-----
Mono-----
Monterey-----
Napa-1---
Nevada-----
Orange66120918--
Placer29112-1
Plumas-----
Riverside71581--
Sacramento12107123-2
San Benito-----
San Bernardino420149--
San Diego10101115--
San Francisco-----
San Joaquin814174-1
San Luis Obispo----1
San Mateo-10---
Santa Barbara-----
Santa Clara21225--
Santa Cruz-----
Shasta--1942
Sierra-----
Siskiyou----1
Solano-210--
Sonoma-1---
Stanislaus141157-1
Sutter4319191
Tehama---7-
Trinity-----
Tulare12-3089-
Tuolumne1----
Ventura-71--
Yolo72085--
Yuba3465-
State Totals528786414714917