TLR3 and viral infectious disease: TLR3 is a pattern recognition receptor used to sense viral nucleic acid, relies on TRIF protein to activate downstream TAK1, activates the NF-κB and MAPKs cascade pathways, regulates the expression of target genes, and leads to the release of a large number of cytokines, which is critical for the activation of the host immune response to virus infection (Yamashita et al., 2012; Verma and Bharti, 2017).