Collectively, compared with U-IHNV, J-IHNV infection caused down-regulation of the dusp4, gadd45α, plk2, and ccn2 genes in a similar manner to EBV, HCV, aMPV/C, and PRRSV, suggesting that these genes may perform the same role during different virus infections, but the exact role within IHNV remains to be clarified. The gene discussed is PLK2; the disease is viral infectious disease.