At 72 hpi, Delta infection upregulated at least two- to seven-fold mRNA expression of IL-1β (Fig. 4A), IL-6 (Fig. 4B), IL-18 (Fig. 4D), CCL2 (Fig. 4F) and IFN-α (Fig. 4G), compared to those at 24 hpi (IL-1β: p = 0.0005; IL-18: p = 0.0008; CCL2: p < 0.0001; IFN-α: p = 0.0007) and 48 hpi (IL-1β: p = 0.0063; IL-6: p = 0.0048; IL-18: p = 0.0289; CCL2: p = 0.0001). This evidence concerns the gene IL18 and infection.