Sarah Rennie – LJI reporter

A rare spillover infection of the highly pathogenic avian influenza to a cow has resulted in an outbreak of the disease on dairy farms in nine U.S. states. In response, Quebec has developed a strategy to prevent, monitor, and protect against the spread of the disease.

The United States Department of Agriculture informed the Canadian Food Inspection Agency (CFIA) that a case of pathogenic avian influenza had been confirmed in dairy cattle on March 25. As of May 12, at least 42 cases were confirmed in the United States. Currently, no cases have been detected in Canada.

According to Dr. Luc Bergeron, the head veterinarian at the Ministère de l’Agriculture, des Pêcheries et de l’Alimentation (MAPAQ), avian flu does not cause mortality in cattle, but it can produce negative economic impacts on a farm. There is a possibility that transmission could occur between dairy and poultry farms, where the consequences are much more catastrophic. He cautions there is also a concern the virus could mutate and become more virulent, or more easily transmissible to humans.

The disease impacts older dairy cows and those that have been in milk for over 150 days. In all cases milk production will drop in an infected cow. The milk will also be thicker in consistency, becoming like colostrum. The animal will also have a decreased appetite. Morbidity is around 10 per cent, and clinical signs usually last from 10 to 14 days.

Bergeron said biosecurity measures should now be implemented on farms and the introduction of new cattle should be limited. Any symptoms should be reported to the CFIA and the MAPAQ, which will conduct an epidemiological investigation. Bergeron confirmed that in the event a positive case is identified, the farm will be required to self-quarantine.