With eight US states confirming that dairy cows have been infected with the bird flu virus, the situation raises concerns among the authorities, producer associations and veterinary associations. Not just in the US, but here in Canada as well.
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Since the first case in Texas (March 25, 2024), organizations working in the livestock sector have been on alert, explains Jean-Yves Perrault, president of the Association of Veterinarians of Quebec (AMVPQ). AMVPQ is affiliated with the American Association of Bovine Practitioners (AABP) covering North America, the Canadian Association of Bovine Veterinarians (ACVB), as well as Dairy Farmers of Canada (PLC), Dairy Producers of Quebec (PLQ), Canadian Food Inspection Agency (CFIA), and the Ministry of Agriculture, Fisheries and Food of Quebec (MAPAQ).
“Since the first case in Texas, there have been communications almost every day from the AABP, governments and different associations that we communicate and follow up with producers and veterinarians,” explains Jean-Yves Perrault. On Friday, the Palestinian Legislative Council organized a webinar to explain the situation to its members.
There are currently no cases of bird flu in livestock in Canada. In the United States, 24 dairy herds were infected within three weeks.
Relative anxiety
Professor Jean-Pierre Vaillancourt of the Faculty of Veterinary Medicine, who specializes in farm biosecurity and strategies to control notifiable infectious diseases, is not too concerned about the health of dairy cows.
However, the fact that the virus that has been circulating for several years does not behave in the classical way worries him more. This virus most affects web-footed birds, which do not die as quickly as traditional highly pathogenic avian viruses. This allowed the virus to reach North America where it was not expected, and it was able to spread throughout America.
Jean-Pierre Vaillancourt is concerned about possible mutations of the virus. “If pigs became infected, I would be concerned because humans share the same receptors with pigs,” he says. The receptors are what allow the virus to infect species.
According to Jean-Pierre Vaillancourt, the first cases were discovered in American dairy cows somewhat by accident. The possibility that the sick cow moved to another state is the cause of its spread in dairy herds is unlikely. The presence of infected birds near the farm is the target cause.
According to him, the recent increase in infected farms is linked to a greater number of tests. “The reason they tested the cows is because they saw that there were a lot of dead birds around these cows,” he explains. When the cows tested positive, other cases were tested.
High alert level
Jean-Yves Perrault explains that the alert level is currently high. The level of risk is expected to decrease with the hot season, because the virus persists for a shorter period in the summer. “Given that there is still a fairly high presence of pathogens in wildlife – wild animals – there is a high degree of vigilance and vigilance,” explains Jean-Yves Perrault.
For a herd of cattle infected with the H5N1 avian influenza virus, the animals are not very sick. Older animals are more affected than young animals. The virus attacks the respiratory system and causes a rise in temperature. As a result, cows may show a slight decrease in milk production. Cow-to-cow transmission is low compared to bird species.
Unlike poultry farms, infected herds of livestock are not slaughtered. The policy is to confine the site to quarantine the herd and put in place biosecurity measures. Sick cows recover after some time.
According to Jean-Yves Perrault, the fact that the dairy herds are confined indoors offers a certain protection. However, he points out that the tendency to take animals outside to improve animal welfare, with animals grazing or exercising, can increase the risks. The virus is found in wildlife. “There is no such thing as zero risk,” he says.
According to Jean-Yves Perrault, it would be unwise to say that there will be no cases in Quebec and Canada. Jean-Pierre Vaillancourt also believes Canada will not be exempt.
Jean-Yves Perrault also explains that livestock associations want to rename the virus because it is no longer just a bird virus. The virus can exist in several species and shows different clinical signs in one species compared to others. Jean-Pierre Vaillancourt explains that there are currently more than 40 mammals infected with the virus and about 272 species of birds.
The CFIA states that pasteurized dairy products pose no risk for consumption. Only one farm worker has been infected so far.
