California currently has four (4) dairy herds under quarantine for H5N1 influenza infection, including one (1) herd that was re-quarantined following a new detection on a previously cleared premises. The re-quarantined herd is located on a dairy that was previously infected and had its CDFA quarantine lifted after three consecutive negative whole-herd tests using weekly bulk tank milk samples.

Progress in California
Only four dairies remain under quarantine statewide, reflecting continued progress in enhanced mitigation measures.
All dairies in California remain under ongoing surveillance as part of sustained monitoring for H5N1.
CDFA lifted the statewide ban on poultry and dairy cattle exhibitions at fairs and shows, effective December 19, 2025.
National Detections
This nationwide outbreak of H5N1 Bird Flu began in poultry in 2022 and was first detected in US dairy cattle in March 2024. All national detections in cattle can be found on the USDA website at: HPAI Confirmed Cases in Livestock | Animal and Plant Health Inspection Service (usda.gov). All national detections in poultry can be found on the USDA website at: Confirmations of Highly Pathogenic Avian Influenza in Commercial and Backyard Flocks | Animal and Plant Health Inspection Service (usda.gov)

Note: The USDA website reports new (first time detections) in dairies; it does not capture when a herd is cleared, ongoing cases, or reinfections on premises that had previous detections.

Bird Flu in Humans
For the most up to date data on bird flu cases in California, please visit CDPH´s Current Bird Flu Situation dashboard. While the risk to the general public remains low, additional human cases of bird flu are expected to be identified and confirmed in California. CDPH recommends that?personal protective equipment (PPE), such as eye protection (face shields or safety goggles), respirators (N95 masks), and gloves be worn by anyone working with animals or materials that are infected or potentially infected with the bird flu virus. Wearing PPE helps prevent infection. Please see CDPH’s Worker Protection from Bird Flu for full PPE guidance. For the latest updates from CDPH, visit Bird Flu (ca.gov). If you have any questions, comments or concerns, you can submit an inquiry directly to CDPH.

be noted the CDFA official website was not accessible in mainland China until late 2025