Re-emergence of a highly pathogenic avian influenza H5N1 virus of clade 2.3.4.4b in poultry in France

Two epidemic waves of the same HPAI H5N1 virus, three months apart, were observed in poultry farms in southwestern France in 2022–2023. The high genetic similarity of the viruses observed between the two waves suggests a re-emergence of the virus probably linked to a still-contaminated environment.