Human Cases
Year-to-date: 54 Counties: 12
There were 7 new WNV positive human cases reported in California last week from the following counties: Fresno (3), Kings (2), Placer (1), and Tulare (1).
5 WNV-related fatalities have been reported to CDPH this year from 5 jurisdictions: Butte (1), Fresno (1), Kings (1), Placer (1), and Tulare (1).
54 human cases from 12 counties have tested positive for WNV in 2025.
Dead Birds
Year-to-date: 140 Counties: 20
There have been 2 new WNV positive dead birds reported in California last week from Santa Clara (1) and Yolo (1) counties.
140 dead birds from 20 counties have tested positive for WNV in 2025.
Mosquito Samples
Year-to-date: 2,605 Counties: 27
There were 105 new WNV positive mosquito samples reported in California last week from the following counties: Contra Costa (1), Fresno (1), Kern (1), Los Angeles (22), Orange (32), Riverside (1), Sacramento (7), San Diego (10), San Joaquin (3), Stanislaus (10), Tulare (16), and Yolo (1).
2,605 mosquito samples from 27 counties have tested positive for WNV in 2025.
A mosquito sample may contain up to 50 individual mosquitoes.
Sentinel Chickens
Year-to-date: 54 Counties: 7
There were 5 new WNV positive sentinel chickens reported in California last week from Los Angeles County.
54 sentinel chickens from 7 counties have tested positive for WNV in 2025.
Horses
Year-to-date: 5 Counties: 5
There was 1 new WNV positive horse reported in California last week from Sacramento County. This is the first WNV positive horse from Sacramento County this year.
5 horses from 5 counties have tested positive for WNV in 2025.