OTTAWA — Canadian dairy farmers are being urged to stay vigilant with biosecurity protocols after the avian flu virus spread in five weeks to 36 American herds in nine U.S. states as of May 1.
The virus also showed up in some American milk samples, though only harmless fragments in pasteurized store-bought samples.
The H5N1 virus — a highly pathogenic avian influenza (HPAI) virus — first turned up at a Texas dairy farm where two cows tested positive on March 25.
While lethal to birds, the virus doesn’t make cattle very sick and pasteurization kills the bug in milk. Raw milk is another story: At a Texas dairy farm, with infected cattle, half of the barn cats died after being fed raw milk, the U.S. Centers for Disease Control reported at the end of April.
The virus’s spread into cats is a concern because, with each new species entered, the chances of passing the virus to humans increases. The current Avian flu strain was first detected in birds in Canada in December 2021 but has not infected any Canadian cattle.
Very few people in the world have ever caught HPAI, but of those who have, the mortality rate was over 52 %, according to Health Canada. For what it’s worth, the World Health Organization views the virus as a global pandemic threat of “enormous concern,” which puts agriculture under the microscope when outbreaks occur in animals.
The risk of transmission from cows to humans is low. Only one worker at a Texas dairy farm has been infected. A mild eye infection was the only symptom in that person’s case.
Nonetheless, internal restrictions within the U.S. quickly sprang up last month to prevent the movement of potentially infected dairy cattle across state lines, with at least 20 states passing regulations to that effect, according to the American Veterinary Association. The U.S. Department of Agriculture joined the action on April 24 by mandating that dairy cattle be tested for the virus as a condition of moving them out of state. The USDA imposed the federal restriction a day after virus fragments were found in American pasteurized milk samples.
Canadian authorities have not yet started testing milk for evidence of the virus.
No dairy herds in this country have been infected with HPAI as of May 1, and the authorities here want to keep it that way. Dairy Farmers of Canada and the Canadian Food Inspection Agency (CFIA) held an online webinar on April 12 for producers to be on the lookout and drive home the biosecurity message.
Though he didn’t take part in the webinar, Lefaivre-area producer Daniel Poirier acknowledged the importance of biosecurity “especially for people who are buying a lot of cows because you never know where they’re coming from.”
Current protocols require producers to isolate newly purchased dairy cattle from the rest of the herd for two to four weeks.
“From my point of view, if you’re not buying cows from everywhere, and you keep your cows inside” during the migratory bird season, “I guess that’s the best we can do,” Poirier said.
He suggested that small hobby farms with a few beef cattle that are always kept outside, often with a small pond, may be more at risk of getting infected from the birds and waterfowl carrying the virus. “That’s probably going to be the place where it starts in Canada.”
“We’ll have our plastic boots ready for guests that are coming. Other than that, I’m not sure what more we can do,” North Augusta dairy farmer Henry Oosterhof said.
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