As shown in Fig. 5, on day 5 of p.i., the expression of caspase-1 was significantly decreased at both mRNA and protein levels, when mice treated with Ac-YVAD-CMK after viral infection for once (Fig. 5a and b) or three times (Fig. 5a to c) compared with that of the infected mice without Ac-YVAD-CMK treatment. The gene discussed is CASP1; the disease is viral infectious disease.