Several studies focused on experimental infection in pigs reported a time-dependent increase of IFN-γ levels in serum, supernatant from cultured PBMCs and IFN-γ mRNA expression in PBMCs and intestinal lymphoid tissues (Solano Aguilar et al., 2001; Dawson et al., 2004, 2005; Verhelst et al., 2015). Here, IFNG is linked to infection.