We show that in Atlantic salmon as in mammals, many ortholog genes are upregulated upon viral infection such as ISG15, UBE1L, USP18, and TRIM25. Atlantic salmon, like several other teleosts, have expanded on the human HERC5 and HERC6 genes where we add HERC8 and HERC9 genes to what was previously defined as teleost-specific HERC7 genes. This evidence concerns the gene USP18 and viral infectious disease.