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An increase in the number of cases of avian flu on farms in the United States, the contamination of herds of cows and reports cases of the illness have been transmitted to humans is of concern to authorities in Quebec and the rest of Canada, and they are monitoring the situation closely.

Avian flu, or more precisely, avian flu of subtypes H5 and H7,  is a reportable disease in Quebec because it is zoonotic — a disease that can be transmitted between animals and humans.

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Cases of avian flu among humans are extremely rare, but last spring three cases among humans, all linked to infected dairy cow farms, were reported in the U.S. Two of the three people infected had eye symptoms and one had a respiratory infection.

Worldwide, 15 human cases of H5N1 flu have been reported since the emergence in 2022 of the clade: A clade is a group of organisms with a common ancestor: two in China, two in Spain, five in the United Kingdom, four in the U.S., one in Ecuador and one in Chile.

Eleven of the 15 cases involved a history of exposure to poultry, said Quebec’s health ministry. “Considering the small number of human cases reported to date worldwide, the virus seems to have a limited ability to infect humans,” the ministry said in an email to La Presse Canadienne.

“We know many humans have shown clinical signs … the good news is the illness is not transmitted between human beings: The day that happens is the day we will miss COVID,” said Dr. Jean-Pierre Vaillancourt, a professor in the faculty of veterinary medicine at the Université de Montréal.

“H5N1 in Canada has been around in Canada for many years, but with low pathogenicity. What is increasing overall, on an international level, are highly pathogenic viruses … . to define highly pathogenic simply to say, for every four infected birds, at least three will die,” Vaillancourt said.

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To him, its is unlikely things will get dicey among humans, but the risk is not zero. “In general, the risk is very minimal … from low to very low. But low to very low, if you are a politician or a consultant to a politician, I would say: ‘You had better not neglect this,’ especially in these post-COVID times,’” he warned.

Vaillancourt, a specialist in the epidemiology of illnesses that can be transmitted between animals and humans, explained avian flu is a virus that replicates and, occasionally, its mutations cause it to become a “super virus.”

To date, no cases of transmission of the virus to humans have been reported in Quebec or elsewhere in Canada.

There is a pandemic among wild birds of a series of highly pathogenic H5N1 variants, Vaillancourt said. “Currently, the H5N1 variant series which concerns us is in Quebec and elsewhere in Canada: It has been identified in at least 489 avian species and more than 200 species of mammals” he said.

In the U.S., the virus has been detected in wild birds in every state, among dairy cows in 12 states, and in more than 200 mammals representing more than 20 species throughout the country.

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In Quebec and the rest of Canada, no infected dairy cow farms or infected dairy products have been detected

Following the detection of highly pathogenic H5N1 among cattle and goats in the U.S., the Public Health Agency of Canada did a risk evaluation in April. It concluded, for the entire Canadian population, the probability of human infection with the H5N1 virus acquired from livestock during the next three months “is still very low.”

But the situation remains worrisome. The provincial health ministry has mandated the Institut national de santé publique du Québec (INSPQ) to come up with recommendations regarding measures to protect workers in the sheep, cattle and pig industries in the event of an outbreak.

“Indeed, this is a concern, the fact it is now present among ruminants such as dairy cattle, baby goats and alpacas,” said Martin Pelletier, an agronomist and coordinator of the Équipe québécoise de contrôle des maladies avicoles (EQCMA).

“That means the virus has taken hold and this means additional exposure for the poultry sector, which is more affected by this disease than other types of animals.”

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Vaillancourt shared his concern. “With cows, it’s that there are more and more mammals, and more and more opportunity for the virus to replicate. At the front lines, it’s a concern for the people who are in contact with these animals,” he explained.

The provincial ministry of Agriculture, Fisheries and Food (MAPAQ) and its partners in industry have invited dairy cattle producers to increase their vigilance and their biosecurity measures.

The Canadian Food Inspection Agency also increased protection and surveillance measures, notably by requiring lactating dairy cows imported from the U.S. to Canada test negative for highly pathogenic avian flu.

In 2022, 23 poultry production facilities in Quebec were affected by avian flu; in 2023, 28 were affected. Since the beginning of this year, the H5N1 virus was detected on three poultry farms, according to the health minister.

“The source of potential contamination is the wild birds that are carriers and they can scatter it, mainly through their droppings or their secretions,” Pelletier said. “The crux of the issue is to form a barrier between the exterior of buildings and the interior.”

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EQCMA director Benoît Fontaine is also concerned about the situation in the U.S. According to him, producers are concerned and have made sanitary improvements — for example, destroying ponds that attract birds, or using separate tractors in the field and keeping them far from buildings.

He described improvements that exceed standards, such as having a bench to separate the entrance to the chicken coop or to wash one’s hands. “I think everyone has increased biosecurity and it’s perhaps one of the reasons the number of cases is down this year,” Fontaine said.

The protocol for a site contaminated with avian flu requires producers destroy all their birds and proceed with the disinfection of the building.

If there were to be cases among cattle, the Canadian Food Inspection Agency would not intervene as it does in the poultry sector, Pelletier said. There would be no depopulation of herds. “It doesn’t have the same impact,” he said. “For cattle, the illness manifests itself with certain clinical signs, but not with mortality,” he explained.

“That’s why, in Quebec, MAPAC, with industry is in the process of developing an action plan for a voluntary self-quarantine and control intervention to minimize the risks of spreading the disease,” Pelletier said.

In addition to a period of self-quarantine for the entry and exit of animals, the milk coming from sick animals or those who test positive would be discarded, MAPAQ said. And for extra protection, the milk from animals in good health in the herd will go to a plant that exclusively pasteurizes milk — this destroys the virus.

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