The results of the analyzes fell on Tuesday.
The deceased seagull found six days earlier in Bourg-lès-Valence (Drôme) had bird flu.
The HPAI virus was indeed detected on the corpse of the bird, reports France Bleu Drôme Ardèche.
The infectious agent, known for its high contagiousness, does not worry the experts for the moment.
It is indeed confined to the wild bird population.
However, the health authorities insist on the need not to let the virus reach bird farms.
The Drôme prefecture has therefore set up a temporary control zone (ZCT), within a radius of 20 kilometers around the place of discovery of the dead seagull.
In the department, 67 municipalities are located in this sector.
Scheduled veterinary visits
A reinforced control zone has also been established within a radius of five kilometers.
It covers Beauvallon, Bourg-lès-Valence, Châteauneuf-sur-Isère, Etoile-sur-Rhône, Pont-de-l'Isère, Portes-lès-Valence, La Roche-de-Glun, Saint-Marcel-lès-Valence and Valence (Drome).
Veterinary visits are planned.
Individuals are asked to prevent contact between domestic and wild birds, and not to approach the latter and the places where they are present.
Avian flu: More than a million poultry euthanized in one month
Avian flu: Death of an infected cat, a first in France