广西宠物犬星状病毒分子流行病学调查及ORF2基因序列分析

发布时间：2018-06-16 18:44

本文选题：犬星状病毒 + 分子流行病学　；参考：《广西大学》2017年硕士论文

【摘要】：犬星状病毒(CanineAstrovirus,CAstV)是引发犬胃肠炎疾病的病原之一。近年来,该病毒在患有肠道腹泻犬中被确定,序列分析发现其属于独有的星状病毒物种,但是该病原在宠物犬中的临床表现形式及其流行规律,目前尚未清楚。因此,本研究旨在了解CAstV在宠物犬群中的临床流行特征和基因型分布特点,为进一步治疗该疾病和了解CAstV流行规律提供科学依据。本研究主要收集2015年11月-2016年08月不同临床特征、不同性别、不同年龄宠物犬群的253份粪便样品。利用RT-巢式PCR(RT-nPCR)方法对CAstV进行临床流行病学调查。研究发现,患有腹泻的犬只CAstV检测阳性率高达25.3%,进一步证实腹泻症状与CAstV感染的相关性。此外,对不同品种、性别和生长阶段的宠物犬感染CAstVs进行分析调查,结果发现,不同品种和性别的宠物犬都能可以感染该病毒,其中幼年犬(≤6月龄)最为易感,感染率高达到18.6%。同时我们发现该病毒主要与犬细小病毒(CPV)伴发感染,其感染率达23.4%。有趣的是,健康犬也可携带该病毒,阳性率为5.9%。这说明CAstV普遍存在于宠物犬中,甚至呈隐性感染。本研究根据部分ORF1b基因构建了氨基酸遗传进化树,旨在进一步了解CAstV的基因型分布特点,首次在广西犬群中发现CAstV可以分为哺乳动物5、3和2型,与它们的氨基酸同源性分别为84.6-100%、97.5-100%和94.9-100%。同时我们根据部分ORF2基因构建了遗传进化树,分析发现,所获得的13株病毒株同属于哺乳动物5型CAstV谱系,但是被分成了两个小分支,分别与中国和意大利毒株在一个分支上,与国内报道有所不同。此外,本研究成功扩增全长衣壳蛋白(ORF2基因),并根据对氨基酸序列进行系统分析和构建遗传进化树。结果表明ORF2基因全长为2325bp,编码775个氨基酸。根据保守性划分为三个区域中,以区域Ⅱ(447aa-730aa)变异较大,除了与2005年意大利毒株和英国毒株(Gillingham/2012/UK)具有较高氨基酸同源性外(95.1-97.6%),其他毒株的同源性相对较低。
[Abstract]:CanineAstrovirus (CAstV) is one of the pathogens causing the disease of canine gastroenteritis. In recent years, the virus has been identified in dogs with intestinal diarrhea. Sequence analysis has found that it belongs to the unique stellate virus species. However, the clinical manifestation and epidemic pattern of the pathogen in pet dogs is not yet clear. Therefore, this study is not clear. To understand the clinical epidemiological characteristics and genotype distribution characteristics of CAstV in pet dogs, to provide a scientific basis for further treatment of the disease and to understand the rule of CAstV epidemic, this study mainly collected 253 fecal samples of pet dogs of different sex and age in 08 months of -2016 in November 2015, using RT- nested PCR (RT-). NPCR) a clinical epidemiological survey of CAstV was conducted. The study found that the positive rate of CAstV detection in dogs with diarrhea was as high as 25.3%, and further confirmed the correlation between diarrhea symptoms and CAstV infection. In addition, the analysis of CAstVs in pet dogs of different varieties, sex and growth stage was analyzed, and the results were found, the pet of different varieties and sexes. The dog can be infected with the virus, of which the young dog (less than 6 month old) is most susceptible and the infection rate is high to 18.6%.. At the same time, we found that the virus is mainly associated with the canine parvovirus (CPV) infection. The infection rate of 23.4%. is interesting that the healthy dog can also carry the virus and the positive rate is 5.9%., which indicates that CAstV is commonly found in pet dogs, even in pet dogs. This study constructed the amino acid genetic evolution tree based on the partial ORF1b gene. The aim of this study was to further understand the genotype distribution characteristics of CAstV. In the first time, the Guangxi canine group found that CAstV could be divided into mammalian 5,3 and type 2, and their amino acids were 84.6-100%, 97.5-100% and 94.9-100%., respectively, according to some O. The RF2 gene constructed the genetic evolution tree. It was found that the 13 strains of the virus were found to belong to the mammalian type 5 CAstV lineage, but were divided into two small branches, which were different from those in one branch of China and Italy, respectively. In addition, this study amplified the full length capsid protein (ORF2 gene) and based on the ammonia. The sequence of basic acid was systematically analyzed and the genetic evolution tree was constructed. The results showed that the total length of ORF2 gene was 2325bp and encoded 775 amino acids. According to conservatism, the gene was divided into three regions, and the variation of the region II (447aa-730aa) was larger, except for the high amino acid homology of the Italy and British strains (Gillingham/2012/UK) in 2005 (95.1-9 7.6%) the homology of other strains is relatively low.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S858.292

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