我国部分地区活禽交易市场H9N2亚型禽流感病毒流行病学调查

发布时间：2018-06-23 05:33

本文选题：禽流感病毒 + H9N2亚型　；参考：《南京农业大学》2015年硕士论文

【摘要】：H9N2亚型禽流感病毒(avian influenza virus,AIV)自1994年在我国首次分离以来,流行范围已扩大至全国各地。该病毒在我国家禽中感染率极高、分布广泛,家禽感染该病毒后,容易造成其他病原继发感染,从而引起家禽呼吸系统疾病和蛋鸡产蛋量下降。H9N2亚型AIV也可以感染人和其他哺乳动物,还可以作为高致病性禽流感病毒的基因供体与其重组,对家禽或公共卫生安全构成严重的威胁。因此,对其进行流行病学调查研究,可以揭示其流行状况和流行规律,从而有助于制定科学的防控策略和应对措施。本研究于2014年4月、8月和10月,在上海、江苏、安徽和广东4省市(长三角和珠三角),随机选取58个活禽交易市场(含25个批发市场和33零售市场),共采集1 2635份家禽拭子样品。样品采集后进行AIV分离、病毒HA和NA基因RT-PCR检测、序列测定和遗传进化分析。结果显示,所检测的1 2635份样品中,H9N2亚型AIV样品总体阳性率为15.10%(1908/12635),H9N2亚型AIV场点阳性率为98.28%(57/58)。该病毒在鸡、鸭、鹅和鸽的样品中的阳性率分别为22.98%(1730/7529)、3.62%(94/2594)、4.08%(67/1643)、2.09%(18/861);该病毒在上海、江苏、安徽和广东四省市的样品中的阳性率分别为 24.11%(688/2853)、8.43%(284/3368)、15.27%(475/3110)、13.95%(461/3304)。研究结果还显示,随着家禽在活禽批发市场内停留时间增加,H9N2亚型AIV分离率呈上升趋势(从停留8 h内的感染率11.45%,上升到停留48 h以上的感染率29.13%),且H9N2亚型AIV病毒在活禽零售市场感染率(34.40%)显著高于活禽批发市场感染率(12.24%)。遗传进化分析结果表明,检出的H9N2亚型AIV全部属于h9.4.2.5分支,该分支的毒株为2007年以来我国H9亚型AIV优势流行分支。从上述结果可以得出以下推论。首先,H9N2亚型AIV在我国长三角和珠三角活禽市场中感染率很高(鸡群中感染率尤高);其次,随着活禽在活禽批发市场内停留时间的延长,以及活禽从批发市场向零售市场的转移,H9N2亚型AIV存在一个显著扩增和扩散的过程,这进而提示活禽交易市场在该病毒传播的过程中,可能发挥类似"放大器"的作用,从而有助于该病毒与其他AIV发生基因重配,同时有助于该病毒感染人类。本文通过对长三角和珠三角活禽交易市场H9N2亚型AIV进行流行病学调查,揭示该病毒在这两大区域活禽市场内的流行状况和动态分布关系,为活禽养殖业更好的发展以及更加科学的研判该病毒的流行动态和流行风险,更有针对性地指导防控工作,提供科学的理论依据.
[Abstract]:H9N2 subtype avian influenza virus (avian influenza virus AIV) has been isolated from China for the first time since 1994, and the epidemic scope has been extended to all parts of the country. The infection rate of this virus is very high in poultry of our country, and it is widely distributed. When poultry is infected with the virus, it is easy to cause secondary infection of other pathogens. As a result, AIV, which causes respiratory diseases in poultry and egg production decline in laying hens, can also infect human beings and other mammals, and can also be used as a gene donor and recombination of highly pathogenic avian influenza virus. Pose a serious threat to poultry or public health. Therefore, epidemiological investigation and study can reveal the epidemic status and the epidemic law, thus contributing to the formulation of scientific prevention and control strategies and countermeasures. This study was conducted in April, August and October 2014 in Shanghai, Jiangsu Province, In Anhui and Guangdong provinces and cities (Yangtze River Delta and Pearl River Delta), 58 live poultry markets (including 25 wholesale markets and 33 retail markets) were randomly selected and 1 2635 samples of poultry swabs were collected. The samples were isolated by AIV, the HA and na genes were detected by RT-PCR, the sequences were sequenced and the genetic evolution was analyzed. The results showed that the overall positive rate of H9N2 subtype AIV was 15.10% (1908 / 12635). The positive rate of H9N2 subtype AIV was 98.28% (57 / 58). The positive rates of the virus in chickens, ducks, geese and pigeons were 22.98% (1730 / 7529) 3.62% (94 / 2594) 4.08% (67 / 1643) and 2.09% (18 / 861), respectively. The positive rates of the virus in Shanghai, Jiangsu, Anhui and Guangdong provinces and cities were 24.11% (6882853) and 8.43% (284P / 3368), respectively. The results also show that With the increase of residence time of poultry in live poultry wholesale market, the AIV isolation rate of H9N2 subtype is on the rise (from the infection rate of 11.45 within 8 hours to 29.13% of live poultry staying for more than 48 hours), and H9N2 subtype AIV virus in live poultry retail market The infection rate (34.40%) was significantly higher than that in live poultry wholesale market (12.24%). The results of genetic evolution analysis showed that the H9N2 subtype AIV belonged to h9.4.2.5 branch, and the strain was the dominant epidemic branch of H9 subtype AIV in China since 2007. The following inferences can be drawn from the above results. First, the infection rate of H9N2 subtype AIV was very high in the live poultry markets of the Yangtze River Delta and the Pearl River Delta in China (especially among chickens), and secondly, with the prolongation of the live poultry staying time in the live poultry wholesale market, the infection rate of AIV was very high in the Yangtze River Delta and Pearl River Delta markets. And the transfer of H9N2 subtype AIV from wholesale market to retail market has a significant process of amplification and diffusion, which suggests that the live poultry market may play a similar "amplifier" role in the transmission of the virus. This helps the virus to rematch with other AIV genes and to infect humans. Based on the epidemiological investigation of H9N2 subtype AIV in the live poultry markets of the Yangtze River Delta and the Pearl River Delta, the epidemic status and dynamic distribution of the virus in the live poultry markets in these two regions were revealed. For the better development of live poultry breeding industry and more scientific study of the epidemic trends and risk of the virus, more targeted guidance of prevention and control work, provide a scientific theoretical basis.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S855.3

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