To investigate this question, we searched the available gene database of tongue sole and selected 8 genes, i.e., IL-1β, IL-8, CsCCK1 (a CC chemokine), CsCXCe1 (a CXC chemokine), TLR9, Myd88, CsISG15 (an ISG15 homologue), and CsG3BP, which are known to be involved in innate immune defense against bacterial and viral infection. This evidence concerns the gene TLR9 and viral infectious disease.