Japanese encephalitis: epidemiology, prevention and current status of antiviral drug development

Introduction: Japanese encephalitis (JE) is the principal viral encephalitis in Asia and is caused by JE virus (JEV). Approximately 3 billion people living in JE endemic countries and foreign travelers to these areas are at risk. Although several vaccines are currently available, approximately 67,900 cases and up to 20,400 deaths occur annually, based on recent estimates. However, no effective antiviral drugs are available to treat JE, regardless of the considerable effort directed toward their development. Areas covered: After general overviews of JE and JEV, we review: i) the recent epidemiological trends; ii) the history and current status of vaccines for JE prevention; and iii) the current status of antiviral drug development for its treatment. Expert opinion: JE is vaccine-preventable. The large number of patients infected with JEV despite the available effective vaccines is partly attributable to low vaccine coverage. To reduce the number of JE cases, vaccine coverage must be increased. Although development of effective antiviral drugs might be far behind, recent progress in novel technologies, including genome-wide screening and computer-based resolution of protein structure, can potentially contribute to the development of antiviral drug candidates. It is expected that JE will become a more controllable infectious disease in the near future.