Compared to the mock-infected ducks at 24 hpi, the lungs of SS-10-infected ducks during the first 3 days of infection showed upregulation that peaked in the mRNA expression level of TLR3 (95.36-fold), TLR7 (146.35-fold), RIG-I (26.29-fold), MDA5 (4.22-fold), and LGP2 (4.77-fold), (Figure 2). Here, TLR3 is linked to infection.