On Oct. 18, 2024, the California Department of Public Health (CDPH) reported that a total of 13 human bird flu cases were confirmed in California. All 13 cases were Central Valley individuals who had direct contact with infected dairy cattle and were confirmed after additional testing by the Centers for Disease Control and Prevention (CDC).

Given the amount of exposure individuals with bird flu infections have with infected cows, evidence continued to suggest only animal-to-human spread of the virus in California. Based on CDC’s genomic sequencing of three California bird flu cases, there was no evidence to suggest an increased ability for the virus to infect or spread between people and no known reduced susceptibility to antiviral medications.