Bird flu in Quebec: worried breeders and infected seals

And we are even beginning to report cases in mammals, including marine mammals: Nearly one hundred harbor seals in St. Louis. Lawrence has been infected.

Recently, this highly pathogenic H5N1 bird flu has actually crossed the species line: in Canada, there are now red foxes (about twenty), striped skunks (5) and a mink.

The United States also counts coyotes, opossums, raccoons and bobcats among mammals with bird flu. “So far, there have been no mammal-to-mammal infections, only bird-to-mammal – probably because the mammal ate the sick bird. This is a reassuring “dead end” to the disease, “continues Manon Racicot. There are mutations that are known to have the potential to adapt to mammals or humans. Currently, she explains, pathogenicity studies are being performed with animal models, such as ferrets, to determine this. potential for transmission between mammals.

Add to that, in Quebec, seals. “NOAA (US Oceans Agency) has also confirmed cases in Maine. We are gathering the information and waiting for confirmations,” notes Karina Laberge of the Regional Communications Branch of Fisheries and Oceans Canada. Tests conducted specifically on seals “have not yet been completed and will be confirmed by the CFIA when the Winnipeg Laboratory approves the results. »

It will not be easy to decide. Although these are all cases of H5N1, there are several “types” of viruses based on recombination with North American strains. “Molecular analyzes are what allow us to know more. If all viruses affecting seals are identical, this would be more in favor of a single source of transmission between seals,” adds the director of the Quebec Center for Wild Animals. Health and specialist in bird pathology, Stéphane Lair.

A first for marine mammals in Canada

In the United States, bird flu in seals had already been documented – 168 New England seals died of the H3N8 influenza virus in 2012 – and earlier this summer the virus was detected in four seals from Casco Bay, Maine. This could explain the high mortality rate recorded there this year: 92 seals had died between May 10 and July 4, without the cause being explained.

“Seals were already known to be susceptible to various influenza viruses, so it is not surprising,” notes virologist from the Laboratory of Veterinary Viral Infectious Diseases, Carl A. Gagnon.

The Quebec Marine Mammal Emergency Network has reported an unusually high number of dead or sick harbor seals in St. Lawrence Estuary in recent weeks. 72 seal carcasses were reportedly retrieved in June. “We have four times more than usual. More than a whole year. Adults and young people, ”confirms Robert Michaud.

This would be the first detection of the H5N1 virus in marine mammals in Canada. Among the animals tested – 16 harbor seals – two thirds are positive for bird flu. The impact this mortality will have on the seal population has not yet been determined.

“This is not worrying about the large seal population, which numbers more than 10,000 individuals, but the red flag has been raised due to the greater transmissibility of this disease,” notes Robert Michaud, who is also scientific director. Training on marine mammals. According to Environment Canada, harbor seals appear to be more likely to develop the disease than gray seals or harp seals, which are also found in Canadian waters.

The prevalence of sick animals, and varieties, also increases the risk of the disease spreading even further within the fauna and crossing other species boundaries. If the threat does not yet weigh on people, summer remains a key period for this new pandemic.

2 million farmed birds

After being reported in the United States last year, the disease was first reported in Canada in December, in Newfoundland, after wreaking havoc in Europe and Asia in hundreds of poultry farms. It appeared in Quebec in April among wild birds: a goose and two snow geese.

Since then, in farmed birds, more than 2 million cases have been infected in Canada, most notably domestic poultry flocks. Quebec is in third place, with nearly 300,000 dead domestic birds, after Alberta (22 places and 937,000 birds) and Ontario (21 places and 560,500 birds). Since the outbreak of the disease in the spring, Canada has had 108 infected farms, including 11 in Quebec.

“Commercial flocks, such as turkey farms, are particularly susceptible to the disease. It is a spectacular mortality rate, with 80% of livestock dying overnight,” says Manon Racicot. It will therefore be necessary to raise the figure to 300,000.

In Quebec, the disease had appeared in the spring among the ducks in Lac-Brome and had contaminated three or four places, in addition to small farms, in the Estrie, Montérégie and Lower Laurentians. Despite the summer heat, which usually damages the flu, it continued to spread.

Globally, the virus appears to follow the migratory routes of wild birds. It had been observed before in 2015 in Canada and it seems that the current version is particularly virulent. And it has many variations. “There are currently four varieties, in addition to the original pedigree, within domestic flocks and seven varieties among wild birds,” explains Mrs Racicot.

Type “A” avian influenza virus, including H5N1, is transmitted through the air (particles in the air) and also through contact with feces.

Although the disease affects all bird species, poultry are particularly vulnerable. Wild ducks are the main reservoir of the disease. Since 2005, it has been jointly monitored in Quebec by the Canadian Wildlife Service, the Department of Forests, Wildlife and Parks and MAPAQ.

It recently expanded to three turkey farms in Saint-Gabriel de Valcartier. A fourth farm is under investigation. The Valcartier region “is currently our priority. We thought we would have a relatively calm summer, but right now we have birds carrying the disease everywhere,” explains the director general of the Quebec Poultry Disease Control Team (EQCMA), Martin Pelletier.

Egg loss, diarrhea, bleeding and sudden death: Symptoms vary by species. Asymptomatic cases are also common in ducks.

A worrying summer for wild birds

Dead wild birds have also been reported in Mauricie, in the Quebec region, in Gaspésie and as far as Îles-de-la-Madeleine. However, it is impossible to know exactly how many hundreds of thousands of wild birds have been infected and died.

“Reporting is done by people, so it’s just an indicator. There are many wild birds that die alone in the wild. What remains worrying is the spread across the country and the diversity of affected birds, ”recalls Martin Pelletier.

In the United States, nearly 165 fatalities were detected between January 1 and June 13, 2002 in 30 U.S. states: mainly terns, cormorants, pelicans, and herons.

“It is still possible that other events will continue to be detected sporadically in the coming months. It is too early to know what the impact will be on the colonies of northern gannets or other species of seabirds in Quebec,” the Ministry of Forestry official said. , wildlife and parks, Daniel Labonté.

Environment Canada also maintains a database of all reported incidents. “The latter is constantly evolving,” says Matthieu Beaumont, biologist and emergency coordinator at the ministry.

One thing is for sure, the list of species affected in Quebec is long: birds of prey (eagles, owls, falcons), scavengers (turkey vultures, crows), waterfowl (geese, ducks, herring and gulls, gannets, common eider ducks) and a wild turkey.

Waterfowl and shorebirds, such as ducks, geese, gulls and gulls, which are most prone to infection, are usually recognized as being the natural reservoirs of the virus. “Birds of prey or scavengers that feed on waterfowl or their carrion are also at greater risk of becoming infected,” confirms Daniel Labonté.

Northern otters and eider ducks, but also black-backed gulls and herring gulls are the wildly affected wild vintages to date. Thus, more than 5,000 carcasses were recently collected in the Magdalen Islands, mainly northern gannets.

Their colony on Bonaventure Island also had its share of deaths with nearly 450 dead. “It is on a small spot of the place – the tourist part – which has 200 nests out of a total of 15,000. We will probably have to make a rule of three and wait for the identification rings to come back – our birds are all ringed – to find out the right figure, ”notes biologist and specialist in marine ornithology, Magella Guillemette from UQAR.

On the other hand, the hatching of the shipowners this year is going well with more than 70% success. “We will be in a better position in the autumn to rule, but that is not the slaughter one would think,” Professor Guillemette will reassure.

Loss of 1,000 eider ducks

There are also more than 900 carcasses of common eider ducks that died on the islands near Rivière-du-Loup between late May and mid-June, reports Jean-François Giroux, retired professor at UQAM and administrator of Société Duvetnor, which monitored avian influenza in eider ducks.

Of this number, 93% are females – the males leave the nests in early June. There are also “360 herring and gulls, as well as cormorants. It is very different from one island to another, and the worst is over, because we have very few new carcasses, ”says M Giroux.

This reminds him of the epidemic of pasteurella (a bacterium) or bird cholera, which had decimated thousands of eider ducks in 2002. “20% of the females had succumbed. The colony has been rebuilt and there are between 25,000 and 30,000 pairs”.

At Ile-aux-Lièvres, located between Saint-Siméon and Rivière-du-Loup, a few seal carcasses were also found.

The hypothesis is that the seals are infected through contact with sick eider birds, with which they share habitat. “It’s reef and there’s a great closeness between the species.” Not in areas where people visit the island, M Giroux specifies. But this is another episode in the spread of the disease.

This text was amended on 14 July with the addition of information in Sections 5 and 6 on the ongoing analyzes on the seals.

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