Interestingly, some of the important hub–hub genes, which are involved in anti-viral interferon response were identified in the purple module, such as IFI6, ISG15, MX1, OAS2, IFIH1, DDX58, DHX58, RSAD2, IFI44, IFI44L, EIF2AK2, ISG20, MX2, IFIT5, IFITM3, OAS1Y, and HERC5, have been suggested by these studies as potential biomarkers for diagnostic and prediction of subclinical BRD at early stage of infection (Sun et al., 2020; Johnston et al., 2021a; Scott et al., 2021). This evidence concerns the gene ISG15 and infection.