IFN-γ was critical in suppression of JEV growth in the CNS but not required for effective clearance of virus from extraneural tissues (Larena et al., 2013), which may throw light on no appearance of classic viral encephalitis (without neurologic disorders and damage) in infected IFNAR–/– mice due to the up-regulated IFN-γ levels detected; however, further research is needed to explore the exact mechanism. The gene discussed is IFNG; the disease is viral encephalitis.