“ It’s worse than anything. » Sylvie Colas is a duck breeder and spokesperson for the Confédération paysanne du Gers. She can’t hold back her anger. Avian flu had already made the 2020-2021 season a dark year. Nearly 500 farms affected by the flu – constituting as many possible sources of transmission – had been identified, 3.5 million poultry had been slaughtered. Records now largely exceeded. On March 10, France had more than 600 farms affected.
More than 4 million poultry have been slaughtered in the south-west of the country, and now the Pays-de-la-Loire region is seeing the epidemic flare up. In just one week, more than 150 new farm outbreaks were detected there. Vendée is the most affected department with “ 187 homes spread over more than a hundred municipalities in the department », informed us the Ministry of Agriculture Friday, March 11 in the morning. He no longer hesitates to talk about a situation “ catastrophic ». According to him, another 3 million poultry remain “ to eliminate ». Around each household, all farms within a radius of five kilometers are “ depopulated ». The ministry hopes to have the area cleaned up by the end of April. The challenge is strategic: many hatcheries and breeder farms are located in this territory. Without them, it is impossible to supply other farms with chicks.
- At the entrance to an intensive farm in the Landes. © Alain Pitton / Reporterre
However, everything had been put in place to avoid this. Lessons had been learned from last year. At the end of September, the ministry had published two decrees to reinforce preventive measures. For the first time, all birds without exception – ducks, hens, turkeys, geese, etc. – had to be returned to the buildings at the first alert. The measure was to prevent contact between wildlife that carries the virus and farms. Biosecurity had been reinforced: limitation of the movement of personnel between farms, systematic cleaning of incoming and outgoing trucks, screening of ducks before transport, etc.
“ There was an effort, the job was done », believes Bernard Tauzia, president of Synalaf. The syndicate represents label poultry producers (organic and Label Rouge). “ In the southwest where there is a lot of open air, all the poultry have been sheltered. To achieve this, the breeders had lowered the density of animals by 25 %. So there are real questions and real disappointment. »
A broadcast of unexpected strength
“ The speed of dissemination seems to go beyond what would be expected in the current context (claustration, very reinforced biosecurity) », already recognized on January 18 the weekly health watch bulletin in animal health. The situation in Vendée and surrounding departments is of particular concern to scientists. “ This is not the first time that she has been affected, but there, it took on an unprecedented scale », observes Barbara Dufour, professor of contagious diseases and epidemiology at the Veterinary School of Alfort. It was thought until then that the region had been preserved from avian flu thanks to its farms closed in modern buildings. “ Breeders there have long been used to biosecurity rules »remarks Gilles Salvat, director of animal health and well-being at ANSES (national health security agency).
In an attempt to explain the Vendée outbreak, scientists are still only guessing. The government mandated ANSES to conduct the investigation. “ A non-negligible hypothesis is that there was such contamination of wildlife that it could contaminate the environment during the uphill migration. », explains Gilles Salvat. Bird flu is usually brought in early winter as the birds descend south. Until now, this had never been the case during the return of migrants. During their journey, they land on lakes, ponds and other wetlands, which are numerous in the Pays de la Loire. The virus then spreads in the environment around the farms.
- The situation as of March 8, 2022. © Ministry of Agriculture
And there, “ it is enough for a person to forget to change their shoes before entering the livestock building »notes Mr. Salvat. “ From the moment the virus finds birds to multiply, it goes very quickly. We have 20,000 poultry that excrete the virus and can in turn contaminate the environment. » The virus is observed in “ air samples up to 70 meters from contaminated buildings », indicated ANSES in an opinion of May 2021. This is how neighboring farms, whether outdoors or confined, are in turn contaminated. Scientists speak of propagation in “ oil stain ».
To this are added the “ human activities »continues Mr. Salvat. “ In Vendée, some of the simultaneously contaminated farms are along a road. Food transport or rendering trucks may have played a role. »
“ As soon as there is an overdensity of ducks in an area, it blazes very quickly »
The scenario was not very different in the southwest, with a few weeks in advance. Some farms close to wetlands have been contaminated by wildlife. The density of farms and poultry did the rest, helped by the movement of personnel (for example teams come to catch the ducks before each transport), trucks (for food, straw, etc.), animals and equipment between farms (straw blowers and other tractors) and “ biosecurity errors » (not changing clothes, badly disinfecting a truck, etc.). The slaughter of sick poultry, involving the movement of rendering trucks and their teams, can aggravate the picture. “ As soon as there is an overdensity of ducks in an area, it blazes very quickly »says Mr. Salvat.
“ It’s worse than last year, when the chickens were outside », observes Sylvie Colas. The free-range breeder sees the current situation as proof that biosecurity measures and confinement are not working. For her, the confinement of animals could even aggravate the situation. “ They are more concentrated, which increases the viral load which is then vented outside the building. » Animal movements, which are more important in so-called farms “ integrated »have also been confirmed as a source of spread of the virus: “ We are on a segmented sector. A breeder makes the ducklings, another makes them grow, a third feeds them, then there is the slaughterhouse. The ducks ride four times in a truck. » She defends her self-sufficient peasant farming model, where the animals remain all their life on the same farm and are often slaughtered on the spot.
- The building of a duck breeder in the Landes. © Alain Pitton / Reporterre
But it is more complicated for this type of breeding to comply with the rules of biosecurity and confinement of poultry. These rules lead “ the breakage of free-range breeding »she assures. “ At the end of the year, 30 % of my producers will quit. Me, a third of my poultry turnover will not be made. We wonder with my husband if this summer, we will not make melon rather than chicken. We are pushed towards the exit. »
This year, the case of the Vendée adds a new difficulty: it prolongs the period when the virus is present, and the poultry locked up. “ If a third of the year there is virus, it means that we cannot produce during this whole period. »she worries. “ Biosecurity jeopardizes free-range farming »also denounced in a forum at the World in February, livestock sociologist Jocelyne Porcher and anthropologists Charles Stépanoff and Frédéric Keck. “ Genetic studies also show that dangerous mutations often appear inside overcrowded industrial structures. »they noted.
“ Lockdown had some effect »
On the veterinarian side, we are more reserved. “ There have been a few fewer outbreaks in the southwest this year, the confinement has had a definite effect », believes Barbara Dufour. The veterinarians interviewed recall that two factors have aggravated the situation this year. First of all, the wild fauna was very contaminated. Furthermore, the 2021-2022 virus is such that animals can shed and spread it for up to two weeks before showing symptoms. So much time during which it can spread discreetly. This is why veterinarians refuse to take a stand for a particular type of breeding.
“ Each system has its risk factors. It is the superimposition on the same territory of these different systems that creates an ecosystem more or less favorable to the spread of the virus. », explains Jean-Luc Guérin, professor of avian pathology at the National Veterinary School of Toulouse. And to control the virus, we therefore need a superposition of measures. “ No single grip is 100% effective % »he assures.
Thereby, “ both confinement and biosecurity are necessary but not sufficient means to control the virus »believes Gilles Salvat. “ Other solutions are being evaluated, including the vaccine. »
What model of breeding ?
The reduction in density is also part of the range of solutions. In a January 2022 opinion, ANSES noted that a reduction of 20 % of the number of farms in a territory slows down the spread of avian flu without stopping it. “ By also lowering the number of ducks in each farm, we could do better »thinks Barbara Dufour . “ A few industrial farms far from each other, this can help contain the spread of the virus. Or a few self-sufficient farms not too close to each other with correct biosecurity rules. »
“ It is not for scientists to decide how far to dedensify »believes Gilles Salvat. “ These are difficult choices for professionals, a significant shortfall. Maybe it’s better to have 50 % less ducks and a production that takes place in good conditions than 0 % in the end because they all had to be cut down because of the virus. » “ When I started as a young veterinarian, the farms had 500 ducks. Today they have 20,000. Foie gras should remain a luxury product », adds Barbara Dufour. So, what kind of breeding do we want? ? The debate is also political and remains to be conducted.