A G57 (BJ/94-like) H9N2 avian influenza virus exhibits enhanced replication and tissue dissemination in chickens compared with a G1-B virus

Graphical abstract

Analysis of H9N2 lineages shows G57 virus replicates, spreads and transmits more efficiently than G1‑B, driven by their gene constellations, enhanced neuraminidase activity, sulphated avian receptor binding and acid‑stable haemagglutinin.