Pathogenesis and origin of tick-borne encephalitis virus isolated in Japan

为明确蜱传脑炎（TBE）流行区，开展流行病学研究，评估北海道株TBE病毒的致病性，检验欧洲TBE疫苗对北海道株TBE病毒的防治效果。我们还对北海地区流行性乙型脑炎病毒株进行了系统发育研究，以确定其起源。结果表明，犬、马血清抗体阳性，表明该病毒主要分布在北海道南部地区。从病毒分离结果中发现北海道地区流行性乙型脑炎病毒的宿主动物为红绒螯虾和斑姬鼠。北海道毒株具有与其他毒株相同的致病性。北海道毒株在几百年前从远东的祖先病毒分化而来。在俄罗斯西伯利亚地区发现了另一种TBE病毒亚型西伯利亚亚型。欧洲型TBE病毒疫苗对北海道、远东和西伯利亚的TBE病毒株均有效。制备了抗TBE病毒北海道株的单克隆抗体，可用于诊断。

We conducted epidemiclogical study to specify the endemic area of tick-borne encephalitis (TBE), evaluated the pathogenicity of TBE virus Hokkaido strain and tested the efficacy of European TBE vaccine to Hokkaido TBE virus strain. We also performed phylogenetic study of TBE virus Hokkai strains to estimate the origin.The results showed that TBE virus distribute in southern part of Hokkaido from the positive antibody results in dog and horse sera. Reservoir animals of TBE virus in Hokkaido were found to Clethrionomys rufocanus and Apodemus speciosus from virus isolation result. TBE virus Hokkaido strains possessed common pathogenicity shared among TBE virus strains. TBE virus Hokkaido strain diverged from ancestor virus in Far East several hundred years ago. Another subtype of TBE virus Siberian subtype was found to distribute in Siberian area of Russia. European type TBE virus vaccine was found to be efficacious to TBE virus Hokkaido, Far Eastern and Siberian strains. Monoclonal antibodies against TBE virus Hokkaido strain were produced and found to be useful for diagnosis.