California health officials have placed more than 650 dairy farms under quarantine as part of aggressive efforts to control the spread of highly pathogenic avian influenza (H5N1). The quarantine affects approximately two-thirds of the state's 984 dairy operations.
State veterinary officials report that while H5N1 is devastating for poultry with a 90-100% mortality rate, its impact on cattle is less severe, affecting only 1-2% of infected cows. However, the situation remains concerning enough to warrant widespread preventive measures.
"While it does impact dairy herds, compared to how it acts in poultry it's much less severe," said Dr. Annette M. Jones, California State Veterinarian and Director of Animal Health and Food Safety Services.
The virus has also been detected in domestic cats, particularly in Southern California. Two cases were reported in Los Angeles County where cats had consumed raw infected milk. According to Dr. Erica Pan, California State Epidemiologist, the virus appears to cause neurological symptoms in felines.
Health officials have noted virus traces in wastewater systems, though they attribute many of these detections to disposal of milk products rather than active infections. Dr. Pan emphasized that pasteurized milk remains safe for consumption, even if it tests positive for viral fragments.
In response to the outbreak, state authorities have distributed over four million pieces of personal protective equipment. A state of emergency declaration has enabled expanded workforce deployment for monitoring and response efforts.
While public health officials maintain that risk to the general population remains low, they advise avoiding contact with sick or dead wildlife. The primary focus remains on protecting workers who have direct contact with infected animals through enhanced safety measures and educational outreach.