On Friday 30^th August, Veterinary authorities in California confirmed a diagnosis of bovine influenza-H5N1 in three dairy herds in the Central Valley marking the 14^th state with affected herds.  The provisional diagnosis was based on symptomatology apparent on August 25^th, followed by laboratory investigation. It is presumed that whole genome sequencing will be performed.

The important question is the extent of infection among approximately 1.5 million cows in the San Jaoquin Valley extending from Bakersfield to Stockton.  Unless California introduces a mandatory testing program similar to Colorado, and then take appropriate action to quarantine affected farms, the dairy industry will be severely impacted.

Based on the reality that H5N1 strain B3-13 is adapted to mammals, appropriate precautions should be taken to prevent exposure of workers.

Karen Ross, Secretary of the California Department of Food and Agriculture stated “We have been preparing for this possibility since earlier this year when HPAI detections were confirmed at dairy farms in other states,” She added “Our extensive experience with HPAI in poultry has given us ample preparation and expertise to address this incident, with workers’ health and public health as our top priorities.” Secretary Ross commented on the financial challenges facing dairy farmers emphasizing the need for urgent action to suppress infection.

Nationally the dairy industry has been reticent to respond to offers by the USDA to participate in monitoring despite financial incentives.