Human Cases
Year-to-date: 2 Counties: 2
There was 1 new WNV positive human case reported in California this week from Sacramento County. This is the first WNV positive human case from Sacramento County this year.
2 human cases from 2 counties have tested positive for WNV in 2026.
Dead Birds
Year-to-date: 166 Counties: 14
There were 33 new WNV positive dead birds reported in California this week from the following counties: Alameda (5), Fresno (1), Los Angeles (5), Placer (1), Sacramento (11), San Bernardino (1), San Mateo (3), and Santa Clara (6).
166 dead birds from 14 counties have tested positive for WNV in 2026.
Mosquito Samples
Year-to-date: 261 Counties: 17
There were 126 new WNV positive mosquito samples reported in California last week from the following counties: Butte (2), Fresno (9), Kern (1), Kings (6), Los Angeles (27), Madera (19), Merced (1), Orange (27), Sacramento (5), San Bernardino (12), San Joaquin (7), Stanislaus (2), and Tulare (8). This is the first indication of WNV from Butte, Kings, and Merced counties this year.
261 mosquito samples from 17 counties have tested positive for WNV in 2026.
A mosquito sample may contain up to 50 individual mosquitoes.
Sentinel Chickens
Year-to-date: 0 Counties:
No sentinel chickens 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.