Comparative pathogenicity of three A(H5N1) clade 2.3.4.4b HPAI viruses in blue-winged teal and transmission to domestic poultry

The recurrent incursions of A(H5N1) clade 2.3.4.4b viruses into North America have resulted in the emergence of reassortant virus genotypes. These genotypes exhibit variations in pathogenicity and host ranges. Blue-winged teal (BWTE) are the most common dabbling ducks in North America and play a crucial role in maintaining and dispersing influenza A viruses (IAVs). In some areas, the migratory pathways of BWTE overlap with densely populated commercial poultry facilities. Despite this, the role of BWTE in the maintenance and spread of A(H5N1) is not well understood, and there is limited data on their susceptibility to A(H5N1) clade 2.3.4.4b viruses. Our study demonstrates differences in BWTE susceptibility to distinct genotypes of A(H5N1) clade 2.3.4.4b viruses. The virus transmission from infected BWTE and lethality in turkeys and chickens were also influenced by the virus genotypes. The findings suggest that BWTE could contribute to the maintenance and spread of highly pathogenic avian influenza (HPAI) viruses, and active surveillance in BWTE is essential.