“very effective” vaccines on ducks

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By John

Two vaccines tested in France have proven “very effective” to protect ducks from avian flu, reported the National Agency for Food, Environmental and Occupational Health Safety (ANSES) and the Ministry of Agriculture, Thursday, May 25, paving the way for a national vaccination. After a lull of a month and a half, the virus has started to flare up again since the beginning of May in the South-West, contaminating more than seventy farms, particularly 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 twenty 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.

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 mulard ducks, bred for foie gras, from the virus. European neighbors are testing vaccines on other poultry species.

Direct transmission “almost stopped”, indirect “abolished”

The French experiment involved several thousand ducks, vaccinated or not. They were euthanized at the end of the process. THE “favorable results provide sufficient guarantees to launch a vaccination campaign from autumn 2023”wrote the Ministry of Agriculture on its website.

The virus circulating in France and around the world was inoculated into a fraction of 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 respiratory or digestive route, summed up Béatrice Grasland, head of the Ploufragan-Plouzané-Niort laboratory, ANSES’s national reference laboratory for avian influenza.

Both vaccines, with results “very similar”have too “almost stopped direct transmission” – when the animals are in close contact – and “abolished” indirect transmission, by air, that is to say potentially from one livestock building 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 not “almost none” contaminated by their neighbor “even in direct contact, in the same pen, with droppings” infected. “It’s very effective”summed up Mme Grasland, noting that, under these conditions, “normally the epidemic does not start”.

Pre-order 80 million doses

Asked, the French laboratory Ceva Santé Animale, whose vaccine is RNA, simply declared that it had applied for marketing authorization from the National Veterinary Medicines Agency (ANMV). It 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 (of the Mulard type, but also from Beijing and Barbary – the latter being rather raised for their meat) because of their “special 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.

Vaccination of “future layer pullets” is also being considered, says the ministry, “with a view to preserving egg production capacities (…) and given the weakening of the sector during past crises”. Vaccination raises technical questions of availability of doses and personnel, as well as economic and diplomatic questions, as poultry professionals fear that export markets will close if animals are vaccinated.