Interestingly, following a primary infection, IFIT1 and IFIT2 genes were repressed more in the resistant animals than in the susceptible animals in the HSF flock, while all members of IFIT family (IFIT1, IFIT2, IFIT3, and IFIT5) were significantly upregulated in the resistant line compared to the susceptible line in the TSF flock (Table 2). Here, IFIT1 is linked to infection.