IL18 and infection: TLRs are the main PRRs for host virus recognition, and during IVA infection, TLR 3/7 is involved in pathogen-associated molecular pattern (PAMPs) identification from IVA by activating myeloid differentiation factor 88 (MYD88), activating downstream transcription factors NF-κB or IRF7, and promoting the expression of pro-inflammatory cytokines such as IL-lβ, IL-18, and type I IFN, respectively (McKinstry et al., 2009).