Researchers mapped two novel, conserved non-neutralizing linear B-cell epitopes on H9N2 avian influenza hemagglutinin using monoclonal antibodies. The work, focused on H9N2, suggests potential diagnostic applications by targeting antibody-epitope recognition that is conserved across viral variants. The study’s emphasis on linear epitopes supports assay development approaches that can be more straightforward than conformational-epitope strategies, particularly for field diagnostics. The snippet does not specify assay sensitivity or breadth across additional strains, but it highlights diagnostic potential grounded in epitope conservation. For avian influenza surveillance programs, diagnostic improvements that maintain performance across drift are central to early detection and downstream public health response. —