Molecular epidemiological studies on Japanese encephalitis and dengue viruses in Asia

本研究通过分子流行病学研究，阐明乙型脑炎尚未解决的越冬问题；该病毒是在温带气候中生存，还是在夏季从热带地区传入，这与在两个流行期发现该病毒有很大不同。本研究还旨在了解病毒毒力因子在登革出血热发病机制中的可能作用。自1953年首次暴发以来，登革出血热一直是东南亚国家的一种主要病毒性疾病。对1935年至1983年在日本和外国分离的日本脑炎病毒株进行了分析。研究中使用了登革3型和4型病毒。这些病毒在白纹伊蚊克隆C6/36细胞中大量培养，并通过聚乙二醇沉淀法和超速离心法从感染液中浓缩纯化。病毒rna是ph…。从丸化病毒中提取更多的烯醇，用蔗糖梯度沉淀法纯化，得到42S病毒粒子RNA。RNA经T1-核糖核酸酶消化后，用多核苷酸激酶和~lt；R^(32)&gt；P-ATP标记。日本乙型脑炎病毒日本分离株的指纹图谱与1980年后的东南亚分离株有很大不同。这一发现支持了这样的假设，即病毒会在冬季在日本的某个地方持续存在。菲律宾分离的3型登革热病毒的指纹模式与印尼分离株的指纹模式非常不同。这些分离株的指纹图谱也与泰国的不同。即使隔离年份相差10年，菲律宾分离株的指纹图谱也很相似，印度支那分离株也是如此。在印度尼西亚同一流行季节，从重度出血热病例分离的3型登革热病毒与从轻度病例分离的3型登革热病毒株有11个点的差异。较少

The study was performed to clarify the unsolved problem of overwintering of Japanese encephalitis; whether the virus persists in the temperate climate or it is introduced from tropical area during the summer time, by using molecular epidemiological studies, which is quite different from those to find out the virus during interepidemic season. The study also aimed to obtain informations on the possible role of virus virulence factor in the pathogenesis of dengue haemorrhagic fever, which has been a major viral disease in Southeast Asian Countries since the first outbreak in 1953.The strains of Japanese encephalitis virus isolated from 1935 to 1983 in Japan as well as in foreign countires was used for the analysis. Dengue virus type 3 and 4 were used in the studies. These viruses were grown in Aedes albopictus clone C6/36 cells in mass culture and the virus was concentrated and purified from the infected fluid by polyethylene glycol precipitation and ultracentrifugation. Viral RNA was ph … More enol-extracted from the pelleted virus, and purified by the sucrose gradient sedimentation to obtain 42S virion RNA. The RNA was digested by T1-RNase and labeled by polynucleotide kinase and <r^(32)> P-ATP. The labeled nucleotides were analyzed by 2-dimensional gel electrophoresis and revealed by the autoradiography.The fingerprints of Japanese encephalitis virus isolated in Japan were quite different from those of southeast Asian isolates after 1980. The finding was in favour of the hypothesis that the virus persists somewhere in Japan during winter season.The fingerprint pattern of type 3 dengue virus isolated in the Philippines was quite distinct from those of the Indonesian isolates. The fingerprints of these isolates were also different from those of Thailand. The fingerprints of the Philippine isolates were rather similar even when the year of isolation showed 10 years difference, so were the Indoensian isolates. There were 11 spots difference between the type 3 dengue virus isolated from severe haemorrhagic fever case from the strain isolated from mild case in the same epidemic season in the Indonesia. Less