2015~2016年广东和广西地区H5亚型AIV分离毒株的遗传演化和小鼠致病性研究

发布时间：2018-11-27 15:48

【摘要】：H5亚型禽流感病毒已在全球超过60个国家的家禽和野鸟中得到分离。监测发现我国流行的H5亚型禽流感病毒不断出现新的毒株类型,近期出现2.3.4.4新型分支H5亚型禽流感病毒的流行,其亚型组合包括H5N2、H5N6和H5N8。然而,这一亚型的病毒的生物学特性,尤其是对哺乳动物的感染性和致病性尚不清楚。本研究对2015~2016年在我国广西和广东地区的活禽交易市场和农场中分离的10株代表性的H5亚型禽流感病毒进行了遗传演化分析和病毒对BALB/c小鼠的感染性和致病性试验。序列分析结果表明,10株病毒共分为7个基因型,所有病毒的HA蛋白裂解位点处均具有5个连续的碱性氨基酸残基,符合HPAIV的分子特征。10株病毒的HA基因节段都属于2.3.4.4分支,NA亚型均为N6亚型。内部基因序列分析发现,10株病毒的内部基因节段与近年来分离的H5亚型禽流感病毒的基因节段亲缘关系较近,说明病毒的进化较为保守。部分毒株内部基因来源复杂,包括H1、H2、H3、H4、H6、H10和H11多种亚型。小鼠的感染性和致病性试验结果表明,H5N6亚型禽流感病毒对小鼠的致病性差异显著。有3株毒株分别造成小鼠在接种病毒后的第7天、第8天和第9天全部死亡;另有3株毒株不能造成小鼠死亡,其中有两株病毒仅引起小鼠体重的轻微变化。所有毒株都可以在小鼠的上呼吸道鼻甲和下呼吸道肺脏中复制。有3株毒株还可以突破小鼠的血脑屏障,在小鼠全身进行复制。研究结果表明当前广东和广西地区流行的H5N6亚型禽流感病毒可以感染哺乳动物宿主,病毒对人类的公共健康构成潜在威胁,需要加强对H5N6亚型禽流感病毒的持续监测和相关生物学特性的研究。
[Abstract]:The H 5 subtype avian influenza virus has been isolated from poultry and wild birds in more than 60 countries around the world. It was found that new strains of H5 subtype avian influenza virus were emerging in China, and 2.3.4.4 new strain of H5 subtype avian influenza virus was found recently. The subtype combinations of H5 subtype avian influenza virus include H5N1 N2H 5N 6 and H 5N 8. However, the biological characteristics of this subtype of the virus, especially its infectivity and pathogenicity to mammals, are unclear. In this study, 10 representative H5 subtype avian influenza viruses isolated from live poultry markets and farms in Guangxi and Guangdong from 2015 to 2016 were analyzed for their genetic evolution, infection and pathogenicity to BALB/c mice. The results of sequence analysis showed that the 10 strains were divided into 7 genotypes and all of them had five consecutive basic amino acid residues at the cleavage sites of HA protein. According to the molecular characteristics of HPAIV, the HA gene segments of the 10 strains belonged to 2.3.4.4 branches, and the NA subtypes were all N6 subtypes. The internal gene sequence analysis showed that the internal gene segment of the 10 strains was closely related to that of the H5 subtype avian influenza virus isolated in recent years, which indicated that the evolution of the virus was more conserved. The internal gene sources of some of the strains are complex, including H1H2H2H3H4H4H6H10 and H11 subtypes. The results of infection and pathogenicity test showed that the pathogenicity of H5N6 subtype avian influenza virus was significant. Three strains of virus caused all the mice to die on the 7th, 8th and 9th day after inoculation, and the other three strains could not cause the death of the mice, two of which caused only slight changes in the body weight of the mice. All strains can be replicated in the upper turbinate and lower respiratory lungs of mice. Three strains can also break through the blood-brain barrier of mice and replicate in the whole body of mice. The results show that the H5N6 subtype avian influenza virus currently prevalent in Guangdong and Guangxi can infect mammalian hosts and pose a potential threat to human public health. The continuous monitoring of H5N6 subtype avian influenza virus and the study of its biological characteristics need to be strengthened.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S852.65

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