Chicken and duck cells showed comparable susceptibility to influenza virus infection and viral RNA accumulation. At 6 hpi with LPAI H2N3, H5N1 tyEng91 or H5N1 tyTR05 virus infection at MOI 1.0, similar accumulation of influenza nucleoprotein (NP) was evident in chicken (A, C, E) and duck (B, D, F) cells as detected by immunocytochemistry. Mock-infected chicken (G) and duck (H) cells show no staining. Comparable accumulation of viral matrix gene RNA between chicken and duck cells at 24 hpi at 1.0 MOI with LPAI H2N3, H5N1-tyEng91 or H5N1 tyTR05 viruses (I). Data were derived from biological replicates of 3 total RNA samples and the data points are mean relative expression values normalized to 18SrRNA expression.