**5. Conclusion**

We analyzed the cases of 105 patients with acute viral encephalitis/encephalopathy who were treated at our emergency center, St. Mary's Hospital, Kurume City during the 10 years from 2002 to 2011. Fourteen HSE cases, 4 of herpes zoster-related encephalitis, 1 of HHV-6 white matter encephalopathy, 4 of JE, 20 of FluE, 3 of mumps encephalitis, and 1 of rotavirus encephalopathy were identified. As other types, 12 cases of viral-related ADEM and 7 cases of non-herpetic limbic encephalitis including anti-NMDAR encephalitis/encephalopathy were observed. The etiology of the remaining 42 cases of viral encephalitis was unknown.

Our results show an upward trend in HSE and JE toward patients over 65 years of age and an increase in adult-onset FluE. Although mortality rates of HSE and JE cases were low, the JE patients remained severe sequelae. The adult FluE patients had more favora‐ ble outcomes compared to the pediatric patients. Specific anti-viral drugs are still limit‐ ed, and acute viral encephalitis/encephalopathy such as FluE overlaps into immunological pathogenesis. Thus, the rapid diagnosis of etiology and pathophysiology and initiation of empiric therapy are required.
