Long‐Distance Avian Migrants Fail to Bring 2.3.4.4b HPAI H5N1 Into Australia for a Second Year in a Row

The current high-pathogenicity avian influenza (HPAI) H5N1 lineage 2.3.4.4b panzootic is having a profound impact on the poultry industry and wildlife [1, 2]. HPAI H5N1 emerged in poultry in 1996 and has caused outbreaks in wild bird populations episodically since 2005 [3], with the epidemiology of the virus changing substantially with the emergence of new lineages. A novel lineage emerged in 2014 (2.3.4.4), which has diversified and caused substantial mortality, including mass mortality events, of wild birds in 2014, 2016 and 2020–present, marine mammals since 2023, as well as ongoing outbreaks in poultry, globally [3]. Understanding the changing phenotype and viral incursion risk following the emergence of novel lineages of HPAI is of crucial importance for the development of short-term…