Change of Japanese encephlaitis virus in Okinawa Island, Japan. -trials for risk assessment of viral invasion and health effectiveness

2014 Fiscal Year Final Research Report

• Project/Area Number: 23510030
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental impact assessment/Environmental policy
• Research Institution: University of the Ryukyus
• Principal Investigator: SAITO Mika 琉球大学, 医学(系)研究科(研究院), 助教 (90235078)
• Co-Investigator(Renkei-kenkyūsha): TADANO Masayuki 琉球大学, 大学院医学研究科, 准教授 (80179712)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 沖縄 / 新興再興感染症 / リスク評価 / 日本脳炎ウイルス / 系統樹 / 進化 / 病原性 / 抗原性

Outline of Final Research Achievements

Japanese encephalitis viruses (JEV) isolated on Okinawa Island were genetically and biologically examined. Okinawan strains are phylogenetically classified into three major clusters: cluster I (1971-1982, genotype (G) 3), II (1986-1992, G3), and III (1998-2008, G1). These appear and disappear around every 15 years. Phylogenetic analysis of Japanese and foreign strains strongly suggested that JEV invaded through Kyushu from north to south. The present study demonstrated that the transmission cycles of JEV were maintained by indigenous and invading viruses. Antigenicity varied with the clusters. The neuroinvasiveness of cluster III in mice was significantly lower than that of the other clusters.

Free Research Field

ウイルス学