A role for TLR3 in viral detection has been suggested by in vitro and ex vivo studies [8,11] but except for a recent study that has clearly shown that TLR3 mediates West Nile virus entry into the brain, causing lethal encephalitis, the functional role of TLR3 in vivo remains unclear [12,13]. The gene discussed is TLR3; the disease is viral encephalitis.