To determine the role of IFN-gamma signaling in the pathogenesis of NSV-induced fatal encephalomyelitis, we have characterized mortality, virus distribution, replication and clearance, and the inflammatory response in IFN-gamma-/- (GKO) and IFN-gamma receptor 1-/- (GRKO) mice in comparison to wild type B6 (WTB6) mice. Here, IFNG is linked to encephalomyelitis.