The cluster I, i.e., top 20% of heatmap consist of DEGs that were up-regulated in co-infection group compared with both other groups, e.g., ifit5, autophagy related protein 9A (atg9a), and irf7b. The smaller groups of genes in cluster II were mostly down-regulated in lice infection alone groups, pre-infection groups and half of co-infection group, e.g., atp2a1, DNA damage inducible transcript 4 like (ddit4l), and bcl 2-like protein 13. This evidence concerns the gene DDIT4L and infection.