STAT1 and cerebellar ataxia: Stat1-/- mice, rag2-/- stat1-/- mice, and rag2-/- ifnar-/- mice died of a typical viral encephalitis 8 to 9 days p.i., based on the symptoms of hunched posture, ataxia, and hyperexcitability, which preceded death by ~18 hours (Table 2).