Avian flu | Vaccinate farmed birds? Not that easy

Hit by an unprecedented avian flu pandemic, the United States is seriously considering launching a massive vaccination campaign for farmed birds. What about in Canada? The point with the D^D Manon Racicot, veterinary epidemiologist with the Canadian Food Inspection Agency.

Vaccination in the sights of the White House

Recently, the New York Times revealed that the Biden administration was considering in high places the possibility of setting up a vaccination campaign for farm birds. The Department of Agriculture has already begun testing vaccine prototypes and initiated discussions with the poultry industry about the feasibility of large-scale vaccination. In the United States, laying hens have been particularly affected by the crisis, to the point that the price of eggs has jumped 70% in one year. “The Americans, their problem is that they have such huge farms that when the virus enters, it is catastrophic. […] They have farms with millions of layers. We don’t have that kind of breeding in Canada,” said Dr.^D Racicot in interview with The Press.

32 herds infected in Quebec

In Quebec, 10 backyards are currently dealing with active infections. They are located in three RCMs: Rouville, Beauharnois-Salaberry and Haut-Saint-Laurent. The very first case detected in a farmed bird in the history of Quebec occurred in April 2022. Since then, 32 “commercial” or “artisanal” farms have suffered an outbreak in the province. About 609,000 farmed birds were “affected” in Quebec and 7.2 million in Canada. “Affected” birds died of the disease or were euthanized on the spot to curb the spread of the virus within the flock or in neighboring farms and buildings. This highly virulent new episode of H5N1 avian influenza began in December 2021 when the virus was detected in a wild bird in Newfoundland.

Is Canada considering vaccination?

“As of today, there is no vaccine available and effective against what is currently circulating that is manageable in terms of administration. We must continue to follow the clinical trials which are in progress”, replies from the outset the D^D Racicot. On the other hand, Canada is closely following the evolution of the file. Although interesting, vaccination poses many challenges. “In Canada, we have several reassortments of the virus. That is, we have H5N1, but there are different genes from the Eurasian line and the North American line. [dans différentes régions]. This means that it takes a vaccine that will be effective for the whole country, ”says M.^me Racicot.

Questions about the method of administration

The second major challenge in vaccinating farm birds is the mode of administration, explains Ms.^me Racicot. “Currently, the vaccines that are available in poultry and which are not yet authorized in Canada, those which are for example used in Mexico or China, are mainly injectable. So it often takes a first dose at the hatchery and a second dose at the farm. There is a vaccine administration challenge in itself, because injecting millions, if not billions of birds, is practically unsustainable,” she says. In an era of labor shortages in the agricultural sector, administering the vaccine in water or bird food could be an attractive option.

International trade

Currently, Canada proves the absence of avian influenza in birds that are exported by demonstrating that they have no antibodies to the disease. “So there, if we vaccinate, we will not be able to demonstrate this,” explains the D^D Racicot. For now, she adds, the majority of trading partners do not accept birds from countries that vaccinate. “It will be a paradigm shift. We will have to have deep discussions with our commercial partners if we decide to vaccinate. We will have to find a way to prove that we are absent from the disease or that the disease is [maîtrisée]. »

Return of migratory birds

With good weather, migratory birds carrying the bird flu virus return. If cases of bird flu have spread at such lightning speed, it is primarily because the virus has never been so present in wild species. Ducks, geese, geese, sandpipers, gannets, common eiders, guillemots, razorbills, crows, crows, snowy owls, eagle-owls, gulls: several dozen species of wild birds have been infected. “There is a very large geographic range and a very large variability in the species currently affected in wild birds,” said Ms.^me Racicot.

Biosecurity

One of the vectors of spread to farms would come from the secretions or droppings of wild birds that would inadvertently end up on agricultural equipment or the soles of workers. Cases on farms are therefore likely to skyrocket in the coming months. The main protective measure for farmers is to follow a strict biosecurity protocol; changing boots before entering the barn is particularly important. “The key message to producers is biosecurity,” says Ms.^me Racicot.