摘要:
自表现产蛋骤降的病死种鸭中无菌采集卵巢以番鸭胚分离到病毒,经对分离的病毒(WR株)进行形态学观察、理化特性测定,发现该病毒有囊膜,直径为30～50nm;对氯仿处理敏感;在pH值为7.2条件下,不凝集鸡、鸭和鹅红细胞。人工感染开产麻鸭能复制出与自然感染病例相同的临床症状和病理变化,并能回收到病毒。应用RT-PCR技术对分离毒进行检测,可扩增到约1kb特异性条带。经测序分析表明,所获得的核苷酸序列第9-777位与坦布苏病毒(TMUV)的同源性最高,为88.7%;遗传进化分析表明WR株病毒与坦布苏病毒、圣路易斯脑炎病毒(SLEV)、以色列火鸡脑膜炎病毒(ITV)、恩塔亚病毒(NTAV)具有相似的祖先,但在系统发生树上处于单独的进化分支。由此推测,WR株病毒不属于现有黄病毒科黄病毒属任何一种,为黄病毒属中的新成员,为国内外首次报道。
Abstract:
A virus WR strain was isolated from the ducks,which experienced abrupt reduction in egg-laying or died of ovarianhemorrhage.The Muscovy ducks inoculated with the WR strain showed pathological effects similar to that of the field cases.The virus could be recovered from the tissues of the sampled ducks in the wild.The viron of the isolated virus had an enveloping membrane and was 30-50 nm in diameter,as observed under electron microscope.The virus WR strain was sensitive to chloroform,and had no haemagglutination activity on chicken,duck or goose sera at pH 7.2.The virus was tested using RT-PCR,and the positive PCR product sequenced and analyzed.The length of the amplified fragment was about 1kb.The sequenced nucleotide had the greatest homogeneity(i.e.,88.7%) with Tembusu Virus at the nucleotide position 9-777.Phylogenetic analysis of Flaviviridae showed the isolated WR strain appeared to share a common ancestor with Tembusu,Louis encephalitis,Israel turkey meningoencephalomyelitis and Ntaya Viruses.However,it seemed to have its own branch on the evolution tree.The results indicated that the isolated WR strain belonged to the genus Flavirirus,but not a member of any of the known groups in the genus.It might be a new Flavivirus species that has not been reported previously.
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