California is grappling with a significant outbreak of highly pathogenic H5N1 avian influenza, which has affected dairy cattle and poultry across the state. In response, State Veterinarian Dr. Annette Jones has announced a statewide ban on dairy cattle and poultry exhibitions at fairs and shows. The ban will remain in effect until the outbreak is brought under control.
H5N1 has spread extensively since August 2024, impacting over 700 dairy herds and 60 poultry flocks, with more than 15 million birds affected statewide. Governor Gavin Newsom declared a state of emergency in December 2024 as cases continued to rise. The USDA’s Animal and Plant Health Inspection Service (APHIS) has reported 149 new cases in the past month alone.
Preventive Measures for Livestock Owners
To curb the spread of the virus, the California Department of Food and Agriculture (CDFA) is urging producers to adopt enhanced biosecurity measures. These include:
- Preventing contact between livestock and wild birds or other infected animals.
- Avoiding the movement or sharing of potentially contaminated equipment.
- Maintaining rigorous sanitation practices to reduce the risk of transmission.
“Enhanced biosecurity is essential to protecting livestock and poultry from this devastating disease,” the CDFA stated, emphasizing the importance of vigilant practices on farms.
Farmers are encouraged to report suspicious illnesses or deaths to their veterinarian or the CDFA Sick Bird Hotline at 866-922-BIRD (2473).
How H5N1 Spreads
Avian influenza is highly contagious and often fatal in birds, with wild waterfowl such as ducks and geese acting as primary carriers. The virus can spread through direct contact with infected animals or indirectly via contaminated surfaces, clothing, and equipment. Dairy farms, particularly those with mixed livestock or located near poultry operations, are at heightened risk.
Recognizing Symptoms
In Dairy Cattle:
- Reduced feed intake and rumination.
- Respiratory symptoms, including nasal discharge.
- Acute drops in milk production, with affected cattle producing thicker, colostrum-like milk or ceasing production entirely.
- Lethargy, dehydration, fever, and abnormal feces.
In Poultry:
- Sudden death and respiratory distress.
- Swelling and discoloration of the wattles, combs, or legs.
- Clear discharge from the nose, mouth, or eyes.
- Neurological symptoms, such as stumbling or twisted necks.
Ongoing Monitoring
The exhibition ban is a critical step in controlling the outbreak, with officials closely monitoring the situation. Updates will be provided as the situation evolves.
For additional resources on managing H5N1 outbreaks, visit the CDFA’s H5N1 Bird Flu Virus in Livestock and HPAIH5N1 in Poultry webpages.
