Human Cases
Year-to-date: 378 Counties: 24
There were 80 new WNV positive human cases reported in California this week from the following counties: Fresno (2), Glenn (1), Los Angeles (59), Orange (11), Riverside (1), San Joaquin (1), Stanislaus (3), Tulare (1), and Yolo (1).
23 WNV-related fatalities have been reported to CDPH this year from 9 jurisdictions: Butte (3), Glenn (2), Kings (1), Los Angeles (6), Orange (5), Sacramento (2), Stanislaus (1), Tuolumne (1), and Yolo (2).
378 human cases from 24 counties have tested positive for WNV in 2026.
Dead Birds
Year-to-date: 734 Counties: 25
There were 22 new WNV positive dead birds reported in California this week from the following counties: Los Angeles (7), Orange (3), San Diego (9), San Joaquin (1), and Santa Clara (2).
734 dead birds from 25 counties have tested positive for WNV in 2026.
Mosquito Samples
Year-to-date: 4005 Counties: 29
There were 102 new WNV positive mosquito samples reported in California this week from the following counties: Fresno (1), Kern (3), Los Angeles (29), Merced (1), Orange (56), Riverside (5), San Bernardino (4), San Diego (2), and Shasta (1).
4,005 mosquito samples from 29 counties have tested positive for WNV in 2026.
A mosquito sample may contain up to 50 individual mosquitoes.
Sentinel Chickens
Year-to-date: 149 Counties: 11
149 sentinel chickens from 11 counties have tested positive for WNV in 2026.
Horses
Year-to-date: 17 Counties: 14
There have been 2 new WNV positive horses reported in California this week from Sacramento (1) and Siskiyou (1) counties. This is the first indication of WNV from Siskiyou County this year.
17 horses from 14 counties have tested positive for WNV in 2026.