extremely significantP < 0.01
The expression of IRF4 in the spleen and brain of Cherry Valley ducks reached extremely significant differences at 1, 3, 5 dpi with DTMUV ( P < 0.01), and the upregulation reached the maximum on the third day in the spleen (96.5-fold, P < 0.01; Figure 4 A); the maximum upregulation (1,572.4-fold, P < 0.01; Figure 4 B) in the brain at 5 dpi.