首次从云南卵形硬蜱中分离到抗原性与森林脑炎病毒相似的两株病毒

TWO STRAINS OF VIRUSES RELATED TO RUSSIAN SPRING SUMMER ENCEPHALITIS VIRUS ISOLATED FROM IXODEX OVATUS IN YUNNAN

森林脑炎又称蜱媒脑炎,是由蜱传播的一组疾病。云南省西部属西部亚热带雨林气候,动物地理划区为西南山地亚区,与缅甸相邻的横断山脉地段为原始针阔叶林混交地区。该地区的地理条件适合多种蜱生长,但是否存在某些未知的蜱媒病毒循环尚不清楚。1988～1989年,我们调查了该地区蜱媒病毒性疾病,从两组卵形硬蜱中分离到两株抗原性与森林脑炎病毒相似的病毒,首次证实在云南存在森林脑炎一类病毒的自然疫源地。

In the sub-tropical region of western Yunnan near Burma (26° north la-, titude and 98.8° east longitude ) in 1988-1989, two strains of viruses ( T56 and T57 were isolated from Ixodex ovatus captured at 2,700 metres above the sea level, T56 and T57 were sensive to acid and ether, and not inhibited by 5- fluorodeoxyuridine. The isolates were 42-62nm globular particles with membrane, and could grow in BHK, Vero, pig embryo kindey cells, rat embryo cells and in chicken embryos. Cross-Hi showed that T56 and T57 could cross-react with viruses of Kyasanur forest disease(KFDV), Powagsan, Langat and Russian spring-summer encephalitis(RSSEV,the Far-Eastern sub-type). It belongs to the tick-borne encephalitis complex.Cross -neutralization test showed that T56 and T57 were cross-reactive with RS-SEV and KFDV, but the neutralization indices with RSSE were higher than with KFD. The antigenicity of the isolates is closed to RSSE. T56 and T57 are the first isolates of RSSEV-related virus from Ixodex ovatus in Yunnan.