TLR3 and viral infectious disease: In the case of neurotropic viral infections, microglia recognize invading viral pathogen-associated molecular patterns (PAMPs) via PAMP recognition receptors (PRRs), such as Toll-like receptor 3 (TLR3) for viral double-stranded ribonucleic acid (dsRNA) (Mogensen and Paludan, 2005; Town et al., 2006; Bowie and Unterholzner, 2008; Li et al., 2019).