Two vaccines tested in France have proven to be “very effective” in protecting ducks from avian flu, the Health Security Agency (Anses) and the Ministry of Agriculture reported on Thursday May 25, paving the way for national vaccination. while the virus gives breeders no respite.
► How did the idea of the vaccine come about?
After a lull of a month and a half, the virus has started to spread again since the beginning of May in the South-West, contaminating more than 70 farms, in particular in the Gers. Each time, infected animals (mainly waterfowl) are slaughtered, preventive slaughter of nearby healthy animals is decided, and poultry production is permanently disrupted.
The repetition and scale of the crises linked to avian flu (more than 20 million poultry slaughtered in 2021-2022 in France, already more than six million in 2022-2023) have convinced European countries to imagine a vaccine strategy.
► What are the vaccine candidates?
In France, an experiment was launched last year around two candidate vaccines developed by the Boehringer Ingelheim and Ceva Santé Animale laboratories. They aim to protect mule ducks, bred for foie gras, from the virus. European neighbors are testing vaccines in other poultry species.
The French experiment involved several thousand ducks, vaccinated or not. They were euthanized at the end of the process.
► What are the results?
The “favorable results provide sufficient guarantees to launch a vaccination campaign from autumn 2023”, writes the Ministry of Agriculture on its website. The virus circulating in France and around the world was inoculated into ducks, previously vaccinated, to measure how much virus they excreted, and if they could still contaminate their congeners.
“Vaccination has resulted in very little excretion of the virus in inoculated animals”, whether by the respiratory or digestive tract, summarized Béatrice Grasland, head of ANSES’s national reference laboratory for avian influenza. Ploufragan-Plouzané-Niort. The two vaccines, with “very similar” results, also “almost stopped direct transmission” – when the animals are in close contact – and “abolished” indirect transmission, by air, that is to say potentially from one barn to another.
When the animals were not vaccinated, “an inoculated animal infected another animal every two hours”, explained the researcher. Conversely, those who were vaccinated were “virtually not” contaminated by their neighbor “even in direct contact, in the same park, with the droppings” infected. “It’s very effective”, summarized Béatrice Grasland, noting that under these conditions, “normally the epidemic does not start”.
► How could the vaccination take place?
Asked, the French laboratory Ceva, whose vaccine is RNA, simply indicated that it had applied for marketing authorization from the National Agency for Veterinary Medicine. He also responded to the call for tenders from the Ministry of Agriculture, which announced in April a “pre-order of 80 million doses”.
According to the ministry, France plans to vaccinate ducks as a priority (mulard type but also Peking and Barbary – the latter being rather raised for their meat) because of their “particular role” in the dynamics of the epizootic. Ducks are very susceptible to the virus and excrete it into the environment even before showing symptoms, which contributes to the low noise spread of avian flu.
The vaccination of “future laying pullets” is also envisaged, indicates the ministry, “with a view to preserving egg production capacities (…) and taking into account the weakening of the sector during past crises”.
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