Ohashi Seiichi, Yoshida Kazuo, Yanase Tohru, Tsuda Tomoyuki
Laboratory of Clinical Virology, Kyushu Research Station, National Institute of Animal Health, 2702 Chuzan, Kagoshima 891-0105, Japan.
J Clin Microbiol. 2002 Oct;40(10):3684-8. doi: 10.1128/JCM.40.10.3684-3688.2002.
A new strain of Ibaraki virus (IBAV) was isolated from cattle showing atypical symptoms of Ibaraki disease. The isolate was genetically characterized, and the genetic diversity and evolution of the capsid proteins of viruses in the epizootic hemorrhagic disease virus (EHDV) serogroup were investigated. The nucleotide sequences of the isolate's viral RNA segments 2, 3, 6, and 7, which encode the viral structural proteins VP2, VP3, VP5, and VP7, respectively, were determined and were then compared against those of the existing strains of IBAV and EHDV, to which IBAV belongs serologically. The nucleotide sequences of segments 3 and 7 were conserved within the EHDV serogroup, particularly well among the strains of IBAV and Australian EHDV. The similarity of the sequence of segment 6 of the isolate to sequences of corresponding segments of the other strains of IBAV and EHDV was found to be about 93%. The similarity of segment 2 of the isolate to segments 2 of the other strains of IBAV and EHDV was less than 70%. Phylogenetic analysis based on the deduced amino acid sequences of segments 3 and 7 revealed that the viruses differed according to their geographical distributions. However, the new isolate of IBAV was categorized as having a distinct lineage in the phylogenetic tree of VP2. These results suggest that the isolate was modified by a reassortment of segment 2 and that it exhibits unique genetic and antigenic characteristics.
从表现出茨城县病非典型症状的牛身上分离出一种新型茨城县病毒（IBAV）。对该分离株进行了基因特征分析，并研究了流行性出血病病毒（EHDV）血清群中病毒衣壳蛋白的遗传多样性和进化情况。分别测定了该分离株病毒RNA片段2、3、6和7的核苷酸序列，这些片段分别编码病毒结构蛋白VP2、VP3、VP5和VP7，然后将其与IBAV和EHDV的现有菌株（IBAV在血清学上属于EHDV）的核苷酸序列进行比较。片段3和7的核苷酸序列在EHDV血清群中是保守的，在IBAV和澳大利亚EHDV菌株中尤其保守。发现该分离株片段6的序列与其他IBAV和EHDV菌株相应片段序列的相似性约为93%。该分离株片段2与其他IBAV和EHDV菌株片段2的相似性小于70%。基于片段3和7推导的氨基酸序列进行的系统发育分析表明，病毒根据其地理分布而有所不同。然而，新分离的IBAV在VP2系统发育树中被归类为具有独特的谱系。这些结果表明，该分离株因片段2的重配而发生了改变，并且表现出独特的遗传和抗原特征。
