#Origin, spread, and interspecies #transmission of a dominant #genotype of BJ/94 #lineage #H9N2 avian #influenza viruses with increased #threat
Abstract The H9N2 subtype of avian influenza viruses (AIVs) is widely prevalent in poultry and wild birds globally , with occasional transmission to humans . In comparison to other H9N2 lineages, the BJ/94 lineage has raised more public health concerns; however, its evolutionary dynamics and transmission patterns remain poorly understood. In this study, we demonstrate that over three decades (1994–2023), BJ/94 lineage has undergone substantial expansion in its geographical distribution , interspecies transmission , and viral reassortment with other AIV subtypes, increasing associated public health risks . These changes were primarily driven by the emergence of a dominant genotype G57. In the first decade, G57 emerged in East China and rapidly adapted to chickens and spread across China . Since 2013, the G57 genotype has expanded beyond China into eight other countries and reassorted with various AIV subtypes to form new zoonotic reassortants . Chickens have played a key role in the gen...