IFNA1 and viral infectious disease: Considering the antiviral function of the IFN response [53, 54], our results suggest that VHSV containing the PP55L amino acid substitution blocks the induction of the IFN response more efficiently than VHSV with PP55 during the early stage of virus infection, which could facilitate the growth of VHSV and thus enhance VHSV virulence in both cells and fish.