H5N1 Bird Flu Cases Stable at 70 with Dairy Cattle Exposures Continuing in Multiple US States

This is Bird Flu Bulletin: Daily H5N1 Update for Wednesday, September 24, 2025. Here are today’s top stories on the status of the H5N1 avian influenza outbreak. Top Stories First, the Centers for Disease Control and Prevention is reporting 70 confirmed human cases of H5N1 bird flu in the United States. Of these, 41 cases are linked to exposure in dairy cattle herds and 24 to poultry operations. California continues to report the highest totals, now up to 38 confirmed cases, with most linked to dairy herds. Since yesterday, no new human cases have been confirmed nationwide, indicating a stable trend at present. Second, animal outbreaks persist, but there are signs of containment. The United States Department of Agriculture Animal and Plant Health Inspection Service reports one new infected cattle herd in Arizona in the past 24 hours, raising the national total to 1,074 affected cattle herds across 17 states. In California, state agriculture officials confirmed one additional dairy herd infection, but also announced 613 dairies have now fully recovered and been released from quarantine. All released herds will remain under bi-monthly surveillance to track for any recurrence. Third, poultry flocks remain under threat. Pennsylvania saw one commercial poultry flock and two backyard flocks test positive for H5N1 in the past month. Local agriculture agencies stress continued vigilance for flock owners, though no new poultry detections were reported today. Case Numbers Comparing today with yesterday, the national human case total remains unchanged at 70. California’s case count is also steady at 38. On the livestock front, Arizona and California were the only states to report new animal herd infections in the last day, signifying a minor increase after a week of flat numbers. Health Authority Guidance CDC continues to stress the low risk to the general public but reminds all agricultural workers and anyone in contact with animals to use personal protective equipment including N95 masks, gloves, and eye protection. The California Department of Public Health urges facilities to follow updated worker safety protocols and report any suspected infections promptly. Expert Interview We spoke with Dr. Maria Chen, a virologist with the Center for Health Security. Dr. Chen: “The pattern of recent infections suggests the virus is currently being well contained within animal populations, with spillover to humans remaining rare and mostly limited to people with high direct exposure. Continued monitoring and strict biosecurity are essential to maintain this progress.” Looking Ahead Tomorrow, public health officials in California and Arizona are expected to release updated data on both human and animal cases, and the USDA is scheduled to provide guidance on fall surveillance efforts for poultry farms nationwide. Attention will also be on progress in vaccine research, with a key update anticipated from federal authorities. That wraps up today’s Bird Flu Bu This content was created in partnership and with the help of Artificial Intelligence AI.