Bird flu: towards a situation that has become uncontrollable in the Gers department?

“The hour is serious”, comments the president of the Chamber of Agriculture of Gers, Bernard Malabirade, on Wednesday 17 May. With highly pathogenic avian influenza (HPAI) outbreaks and uncontrollable spread, concern is growing. The crisis cells continue to face an unprecedented situation for the sector. Yesterday 24 outbreaks were confirmed in the Gers and 9 are suspect. Veterinarians, the Interprofessional Committee of Foie Gras Palmiped and the Chambers of Agriculture of the South West met to take stock of the situation.

Why does this episode take place in the spring?

This is the question that insiders are asking themselves, but also consumers in the Gers or neighboring areas. Why and how did the virus reappear at this unusual time of year? “We are in a health situation that changed a few years ago with a completely new phenomenon that emerged in Asia 25 years ago and which spread with the migratory corridors,” recalls Jean-Luc Guérin of the National Veterinary School of Toulouse.

The department is no stranger to the H5N8 and H5N1 viruses. 2016, 2021 and 2022: new outbreaks are detected every year. “There is a gradual increase in the degrees of virulence and the acquisition of certain properties. In other words, the genetics of the virus has evolved. But the Gers and neighboring departments are not the only ones affected by H5N1. The latter has been detected, for a year, also in the American continent.

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The first case in Brazil was also notified on Tuesday. “The first introduction to the territory takes place through the wild sector, in particular by aquatic birds. This does not mean that it takes place through direct contact with farms”, underlines Jean-Luc Guérin.

So how did the virus get into the buildings where the ducks are kept? This spread of the virus could have occurred through several factors, in particular due to biosecurity gaps. When a home is contaminated, the spread can then accelerate by aerosol over a radius of a few kilometers.

Epidemiological investigations are ongoing to determine the causes of this active spread. To explain this reappearance in the Gers area, Jean-Luc Guérin speaks of the hypothesis of a “local loop”. Some areas may, in fact, be in favor of a “stabilization of the virus”. The “migratory” cause could in fact be excluded, the data show a low migration of birds these days.

End of fattening south of the Garonne, preventive depopulation

The state services do not fail to take into consideration the territorial dimension of the HPAI risk. In this sense, various strategies have been implemented around the focolare in the departments concerned and in particular in the Gers. Reflection is underway on the implementation of strengthened monitoring tools in order to understand how the virus has been able to maintain itself in the environment of index outbreaks at four-month intervals.

“No one saw this virus coming,” notes François Landais, a veterinarian at the Anibio group. To limit the diffusion it was necessary to implement “the end of fattening south of the Garonne”, he explains. And this, until May 26th. “Preventive depopulation started less than a week ago,” adds Sophie Pellerin of the New Aquitaine Regional Directorate of Food, Agriculture and Forestry.

For this measure, the Vic-Fezensac slaughterhouse was requisitioned for the slaughter of healthy and over 42 days old tested animals. For all sensitive species, depopulation can be carried out on site within a radius of 0 to 1 km around the outbreaks. Restricted areas have also been strengthened and surveillance strengthened.

191,178 animals to be slaughtered?

In 8 days, this is the number of animals over 42 days old to be depopulated in the slaughterhouse in the departments of Gers, Landes, Pyrénées-Atlantiques and Hautes-Pyrénées. The current slaughter capacity is 242,000 animals. Three slaughterhouses have been commandeered in the three departments. Specialized intervention teams were also mobilized for preventive depopulation carried out on site for animals less than 42 days old.