Gao G F, Zanotto P M, Holmes E C, Reid H W, Gould E A
Institute of Virology and Environmental Microbiology, Oxford.
Acta Virol. 1997 Oct;41(5):259-68.
Following the demonstration that the tick-borne encephalitis (TBE) subgroup viruses are distributed as a cline across the Northern Hemisphere (Zanotto et al., 1995), we have analyzed the dispersal pattern of louping ill (LI) virus, the most westerly located member in the cline. A total number of 21 LI or LI-related virus E gene sequences have been used for a detailed molecular analysis of the evolution, phylogeny and geographical distribution of LI virus in the British Isles and Ireland. The results show that LI virus is genetically stable in general but minor differences enable its separation into four genetically distinct subtypes (genotypes) with clear geographical correlation, designated Type 1 in Scotland and England, Type 2 in Scotland, Type 3 in Wales and Type 4 in Ireland. These data demonstrate that geographically independent evolution of LI viruses has occurred. The molecular systematics and substitutional parameters analyses combined with the clinal distribution of the TBE virus complex allow the assignment of the origin for both Negishi (NEG) virus and a Norwegian isolate to the British Isles. Moreover, proposals for the classification of LI and LI-like viruses which cause encephalomyelitis in sheep, goat or cattle are presented.
在证实蜱传脑炎（TBE）亚组病毒呈渐变群分布于北半球之后（扎诺托等人，1995年），我们分析了卢平病（LI）病毒的传播模式，它是该渐变群中位于最西部的成员。总共21个LI或与LI相关的病毒E基因序列被用于对不列颠群岛和爱尔兰的LI病毒的进化、系统发育和地理分布进行详细的分子分析。结果表明，LI病毒总体上基因稳定，但细微差异使其可分为四个基因上不同的亚型（基因型），且与地理区域有明显关联，在苏格兰和英格兰为1型，在苏格兰为2型，在威尔士为3型，在爱尔兰为4型。这些数据表明LI病毒在地理上发生了独立进化。分子系统学和替代参数分析结合TBE病毒复合体的渐变群分布，使得根岸（NEG）病毒和一株挪威分离株的起源地被确定为不列颠群岛。此外，还提出了对在绵羊、山羊或牛中引起脑脊髓炎的LI和LI样病毒进行分类的建议。
