API5 and infection: Results showed a significant increase in API5 mRNA levels in hemocytes, with the most prominent rise occurring at 24 h post-infection (Figure 3C), a similar trend was observed in API5 protein expression levels (Figure 3D), meanwhile, the copy number of virus particles in different time periods indicated that WSSV replicated smoothly in mud crab (Figure 3E), the above data strongly suggest the association of API5 with antiviral immune response in mud crab.