Khasan virus, a new ungrouped bunyavirus isolated from Haemaphysalis longicornis ticks in the Primorie region

Strain LEIV-776P, possessing no haemagglutinating activity was isolated in 1971 in the Primorie region (U.S.S.R.) from Haemaphysalis longicornis Neumann 1091 tick. Complement fixation (CF) tests revealed no antigenic relationship with 24 antigenic groups of arboviruses or 21 ungrouped viruses isolated from ticks. The virus isolate contains RNA and is relatively sensitive to ether and sodium deoxycholate; it is pathogenic for suckling mice and two-week-old white mice by the intracerebral route, and replicates in primary cultures of chick and duck fibroblasts and green monkey kidneys and in a continuous line of pig embryo kidney cells without any cytopathic effect. According to electron microscopy, its size is 90-110 nm. Its morphological properties permit to classify it as a member of the family Bunyaviridae.