The induction of expression of IFNβ has been shown to occur in vitro at 3–6 hours p.i [33], while in the livers and spleens of immunized mice in this study it occurred at 3 hours p.i. Taking into account that after host infection, the virus is likely conveyed to the lymph nodes where it first replicates before it can spread to the liver and other organs [2], our results show the ability of RVFV to rapidly spread in the infected host. Here, IFNB1 is linked to infection.