Compared to the non-infected animals, all the infected groups presented a significant upregulation of the ISGs Mx1 and ISG15 and of the C–X–C motif chemokine ligand 10 (CXCL10) messenger RNA (mRNA) expression at day 2 and 5 post-infection, with no difference between the placebo and the IFN-treated groups (Fig 4A). The gene discussed is ISG15; the disease is infection.