Following 24 h of infection with H5N1-tyEng91 or H5N1-tyTR05 virus, members of JAK-STAT signalling pathway (JAK1, IFN-α receptor 1 [IFNAR1], STAT-3 and protein inhibitor of activated STAT 2 [PIAS2]) were down-regulated in chicken cells. The gene discussed is STAT3; the disease is infection.