Evolution and Spread of Y280-Lineage H9N2 Low Pathogenicity Avian Influenza Viruses in Korea, 2020-2023.

In 2020, Y280-lineage H9N2 low pathogenic avian influenza was detected in South Korea for the first time. Active surveillance from live bird markets (LBMs) and farms revealed the continuous circulation of Y280-lineage H9N2 viruses, replacing the previously indigenous Y439-lineage and becoming dominant in South Korea. Antigenic mapping showed a substantial antigenic difference between the Y280 and Y439-lineage viruses.

Machine learning assessment of zoonotic potential in avian influenza viruses using PB2 segment.

Background: Influenza A virus (IAV) is a major global health threat, causing seasonal epidemics and occasional pandemics. Particularly, Influenza A viruses from avian species pose significant zoonotic threats, with PB2 adaptation serving as a critical first step in cross-species transmission. A comprehensive risk assessment framework based on PB2 sequences is necessary, which should encompass detailed analyses of specific residues and mutations while maintaining sufficient generality for application to non-PB2 segments.