Signal Avian influenza in US dairy cattle since 2024; year-round in Dutch wild birds since 2021

Summary

The report regards the outbreak of highly pathogenic avian influenza in US dairy cattle since 2024 as a new development that calls for vigilance. In the Netherlands bird flu has become a permanent risk, and whereas it used to be mainly a winter phenomenon, since 2021 it has fundamentally changed to occur year-round among wild birds. Highly pathogenic virus introduced from poultry has also been present in wild birds in Asia since 2004 and in Europe since 2005, so it can enter poultry farms directly. In the Netherlands infections have been confirmed in several wild mammals, including foxes, badgers, otters and polecats, and recently in a seal. In 2025 young cats in the Netherlands died of bird flu for the first time.