NFKB1 and infection: Firstly, the duck monocytes/macrophages were pretreated with SP600125 (JNK inhibitor,10 μmol/mL), LY3214996 (ERK inhibitor, 5 μmol/mL), TAK-715 (p38 inhibitor, 5 μmol/mL), BAY-11-7802 (NF-KB inhibitor, 5 μmol/mL), or solvent DMSO for 1 h, and then infected with 5 MOI of the CHa strain for another 1 h, after infection the cells were washed with PBS and the same concentration of each inhibitor was added.