Human Cases
Year-to-date: 67 Counties: 15
There were 8 new WNV positive human cases reported in California this week from the following counties: Kings (1), Los Angeles (1), Placer (1), San Joaquin (3), Sutter (1), and Tuolumne (1). These are the first WNV positive human cases from San Joaquin and Sutter counties this year.
6 WNV-related fatalities have been reported to CDPH this year from 6 jurisdictions: Butte (1), Fresno (1), Kings (1), Placer (1), San Joaquin (1), and Tulare (1).
67 human cases from 15 counties have tested positive for WNV in 2025.
Dead Birds
Year-to-date: 146 Counties: 21
There were 6 new WNV positive dead birds reported in California last week from the following counties: Los Angeles (1), Merced (1), San Diego (3), and Solano (1). This is the first WNV positive dead bird from Merced County this year.
146 dead birds from 21 counties have tested positive for WNV in 2025.
Mosquito Samples
Year-to-date: 2,666 Counties: 27
There were 61 new WNV positive mosquito samples reported in California last week from the following counties: Fresno (7), Kern (2), Los Angeles (8), Orange (25), Riverside (1), San Bernardino (1), San Diego (9), San Joaquin (3), Solano (3), Stanislaus (1), and Yolo (1).
2,666 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: 55 Counties: 8
There was 1 new WNV positive sentinel chicken reported in California last week from Colusa County. This is the first WNV positive sentinel chicken from Colusa County this year.
55 sentinel chickens from 8 counties have tested positive for WNV in 2025.
Horses
Year-to-date: 5 Counties: 5
5 horses from 5 counties have tested positive for WNV in 2025.