猪毛尾线虫的检测及其ITS序列分析

Detection of Trichuris suis and Its ITS Sequence Analysis

毛尾线虫俗称鞭虫,为肠道常见寄生线虫,可感染人和多种动物。2015年11月,江西某猪场育肥猪出现腹泻症状,粪便带黏液和血液,部分病猪死亡;剖检发现猪肠道内充满了线状虫体;依据发病猪症状和虫体、虫卵的分析,初步确定该病为猪毛尾线虫病。采用通用引物扩增分离线虫的基因组内转录间隔区(internal transcribed spacer,ITS),结果显示分离虫体的ITS序列与猪毛尾线虫ITS序列的核苷酸同源性高达99.8%,从基因水平进一步证实了该病原为猪毛尾线虫;系统进化分析表明其与18条来自不同地区毛尾线虫的ITS序列相似性均>93.5%,其中,与湖南益阳地区的猪毛尾线虫(AM993005)亲缘关系最近。试验结果为建立猪毛尾线虫的分子生物学诊断方法奠定了基础。

Trichuris suis are the common intestinal parasites in human and animals.In November 2015,the finishing pigs in a farm in Jiangxi province had severe diarrhea with blood in feces,leading to die of some pigs.Anatomical diagnosis found the intestine was filled with linear-like worms.Through the observation of the onset symptoms,morphology of the worms and eggs,it was initially identified as infection of Trichuris suis.Then a 1,345 bp fragment of the internal transcribed spacer（ITS）sequence was amplified and sequenced.Blast analysis indicated that ITS sequence had 99.8%identity with that of Trichuris suis.Phylogenetic analysis showed the relationship with other strains was far,but the nucleotide homology was still more than 93.5%.Most importantly,it had highest identities with a Trichuris suis strain（AM993005）from Yiyang of Hunan Province,China.Therefore,this study provided a technical reserve and theoretical guidance for the establishment of the molecular biology diagnostic method of Trichuris suis.