Acute Viral Encephalitis/Encephalopathy in an Emergency Hospital in Japan: A Retrospective Study of 105 Cases in 2002 – 2011

Herpes simplex encephalitis (HSE) has come to be widely recognized as diagnosable and treata‐ ble at early stages of the disease. The incidence of encephalitis/encephalopathy resulting from other members of herpesvirus group such as varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpes virus (HHV)-6 has also tended to increase in both healthy and immunocompromised patients (Shoji et al, 2002). In sharp contrast, the inci‐ dence of Japanese encephalitis (JE) in Japan has dramatically decreased to a few patients per year. However, JE remains a threat among the elderly and individuals with decreased or absent immunity to the JE virus (Ayukawa et al, 2002). Influenza-associated encephalopathy (FluE) is a threat for adults as well as children (Lee et al, 2010, Umemura et al, 2011, Watanabe et al, 2012). In the present study, we retrospectively analyzed the cases of 105 mainly adult patients with acute viral encephalitis/encephalopathy at our emergency hospital, St. Mary’s Hospital, Kur‐ ume City during a recent 10-years period from 2002 to 2011.We present here our preliminary re‐ port of the changing patterns in HSE, JE and FluE during the past 10 years.