Human Cases
Year-to-date: 5 Counties: 5
There were 3 new WNV positive human cases reported in California this week from the following counties: Kings (1), San Diego (1), and Tulare (1). These are the first WNV positive human cases from Kings, San Diego, and Tulare counties this year.
5 human cases from 5 counties have tested positive for WNV in 2026.
Dead Birds
Year-to-date: 251 Counties: 20
There were 46 new WNV positive dead birds reported in California this week from the following counties: Alameda (2), Contra Costa (1), Los Angeles (5), Orange (1), Sacramento (21), Santa Clara (13), Sutter (1), Yolo (1), and Yuba (1). These are the first WNV positive dead birds from Sutter and Yuba counties this year.
251 dead birds from 20 counties have tested positive for WNV in 2026.
Mosquito Samples
Year-to-date: 1001 Counties: 25
There were 331 new WNV positive mosquito samples reported in California this week from the following counties: Butte (2), Fresno (9), Imperial (1), Kern (16), Kings (12), Lake (1), Los Angeles (19), Madera (78), Merced (11), Orange (63), Placer (14), Riverside (2), Sacramento (10), San Bernardino (7), San Diego (2), San Joaquin (12), Shasta (2), Stanislaus (13), Sutter (5), Tulare (40), and Yolo (12). This is the first indication of WNV from Lake and Shasta counties this year.
1,001 mosquito samples from 25 counties have tested positive for WNV in 2026.
A mosquito sample may contain up to 50 individual mosquitoes.
Sentinel Chickens
Year-to-date: 2 Counties: 1
There were 2 new WNV positive sentinel chickens reported in California last week from Los Angeles County. This is the first WNV positive sentinel chicken from Los Angeles County this year.
2 sentinel chickens from 1 county have tested positive for WNV in 2026.
Horses
Year-to-date: 1 Counties: 1
1 horse from 1 county has tested positive for WNV in 2026.