The US Centers for Disease Control and Prevention (CDC) today confirmed another human H5N1 avian flu case in California, which likely reflects follow-up testing of a presumed positive involving a San Francisco child. The latest confirmation puts the national total since early 2024 to 67 cases, of which 38 are from California.

San Francisco health officials announced the presumed-positive case, which involved a child with fever and conjunctivitis who was not hospitalized and has fully recovered, on January 10. Though most of California’s cases involve people with occupational exposure to sick dairy cows, the state has reported two illnesses in people with undetermined exposure sources, both of them children. The California Department of Public Health (CDPH) also updated its H5N1 total to 38 today, which adds a second illness from an undetermined exposure source.
In an updated risk assessment today, the CDC said the H5N1 risk to the general public remains low, but is higher in farm workers exposed to sick animals or their byproducts, backyard bird flock owners, animal care workers, and animal health and public health responders.
The CDC also spelled out the factors that would cause it to raise its risk assessment, including more efficient virus transmission, increased disease severity, more widespread cases, and great impacts from genetic changes in the virus.
USDA confirms more detections in poultry and dairy cattle
In other developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed more H5N1 outbreaks in poultry from three states. They include a broiler farm in Maryland’s Caroline County that has nearly 229,000 birds and two commercial turkey farms in Ohio, one in Darke County and the other in Mercer County, that, taken together, have about 15,000 birds. APHIS also confirmed the virus in a backyard flock in Phillips County, Kansas.
Also, APHIS confirmed 2 more H5N1 detections in dairy cattle, both in California, which pushes the national total to 927 and California’s total to 710.