中国狂犬病2007年流行特征及病毒N基因分子流行病学研究

发布时间：2018-04-24 19:18

本文选题：狂犬病 + 狂犬病病毒　；参考：《中国疾病预防控制中心》2010年硕士论文

【摘要】： 狂犬病是由狂犬病毒感染引起的一种人兽共患的烈性传染病,病死率几乎为100%。许多动物既是储存宿主又作为传播媒介在世界范围内维系并传播着本病。近年来狂犬病在我国持续高发,2003突破2000例,2007年发病死亡人数已达到3302例,除青海、西藏外其余29个省、区均有病例报告。近年在狂犬病高发省区开展了一系列的调查研究,但对于中、低发地区疫情的快速上升和地域性扩散尚未引起足够的重视,也缺乏相应的调查。为此,本研究在以往工作的基础上,分析了我国2007年狂犬病疫情特征,根据我国狂犬病病例的流行和地理分布情况选择流行程度不同的七个省(自治区、直辖市)收集标本,检测和分析不同宿主动物感染狂犬病病毒及病毒N基因遗传变异状况,通过与高发病地区调查结果进行比较,探讨我国狂犬病高、中和低发病地区狂犬病的流行和分布和狂犬病病毒遗传变异间关系,为更为有效控制狂犬病疫情的蔓延提供科学依据。 2007年狂犬病疫情分析显示我国狂犬病流行继续升高并呈现从南部向北部、从高发向低发地区蔓延的趋势,病例以夏秋季节为多、男性多于女性。在狂犬病流行程度不同的七个省收集了382份不同宿主动物来源的组织标本,经直接免疫荧光法和RT-PCR两种方法检测出狂犬病毒感染阳性的标本81份,选择N基因编码区下游720个(634-1353位)核苷酸序列进行扩增和测序,获得34份病毒标本相应区段的核苷酸序列。基因序列同源性分析结果：34个N基因核苷酸序列同源性为87.5-100%,推导的氨基酸序列同源性为93.3-99.6%,表明该区段核苷酸序列的变异主要是同义突变。N蛋白该区段氨基酸序列包含Ⅰ、Ⅲ、Ⅳ个抗原位点及Th细胞表位,34个病毒标本N基因的这些功能位点都高度保守,而且在该氨基酸区段都具有389位丝氨酸磷酸化位点和375位苏氨酸次要磷酸化位点,提示N基因功能位点的保守性与N基因的遗传稳定性有关。 N基因核苷酸序列种系发生树分析显示,34个病毒标本都属于基因Ⅰ型狂犬病毒,具有按来源省份不同进一步进化为不同群或亚群的地域性特征,且存在野生动物与家养动物间的相互感染与传播。在进化趋势上存在由西南地区向中部地区进而向东部地区和东南部地区传播流行的可能性；与近几年狂犬病地域分布和扩散趋势相吻合,说明我国狂犬病的流行与狂犬病病毒的分布和传播有着直接的关系。在与国际毒株的比较分析中,所有我国标本(Ⅰ、Ⅱ、Ⅲ群)都集中在一个大分支下,表明我国狂犬病病毒区别于其它国家的病毒,基本在本国及周边地区循环。在中国分支下,还包含印度尼西亚和泰国这两个亚洲国家的2株狂犬病病毒,其中Ⅱ群的云南毒株与泰国犬分离株存在极近的亲缘关系,而与其他33个本国毒株(Ⅰ、Ⅲ群)的亲缘关系相对较远,结合历史背景及多方面因素分析,东南亚和我国之间极可能存在着狂犬病病毒的交互感染和传播。研究结果表明,我国狂犬病近几年疫情继续升高并呈现地域性扩散,狂犬病病毒的传播和扩散可能是造成疫情快速上升和流行区域扩大的原因之一。我国狂犬病病毒N基因核苷酸变异呈现地域特征,其编码蛋白上的抗原位点均高度保守；N基因种系发生树分析显示这些地区流行的均为基因Ⅰ型狂犬病病毒,并且来源于同一省份的病毒显示出更高的亲缘特性。病毒标本间进化关系结合流行病学背景显示,我国野生动物与家养动物之间,本国动物与邻国动物之间,可能均存在着狂犬病毒的交叉感染和传播。本研究通过对我国狂犬病流行程度不同的地区野生动物和家养动物间狂犬病毒流行株的N基因分子特征进行了深入详细的分析,探讨了我国狂犬病病毒遗传变异特点及其与流行的关系,以便为更加科学地制定我国狂犬病预防控制措施提供科学依据。
[Abstract]:Rabies is a kind of zoonotic infectious disease caused by rabies virus infection. The mortality rate is almost 100%.. Many animals are both the host and the media in the world. In recent years, the incidence of rabies in China, 2003 breakthroughs in 2000 cases, and the number of deaths in 2007 have reached 3302. In Qinghai and the other 29 provinces and regions outside Tibet, case reports have been reported. In recent years, a series of investigations have been carried out in the provinces of high incidence of rabies. However, the rapid rise and regional spread of the epidemic in low hair areas has not yet aroused enough attention and lack of corresponding investigation. On the basis of previous work, this study has analyzed China's 2007. According to the epidemic and geographical distribution of rabies cases in China, seven provinces (autonomous regions and municipalities directly under the central government) were selected according to the prevalence and geographical distribution of rabies cases in China. The genetic variation of rabies virus and N gene in different host animals was detected and analyzed, and the results were compared with the results of the high incidence area. The relationship between rabies epidemic and distribution and the genetic variation of rabies virus in high rabies, middle and low incidence areas provides a scientific basis for more effective control of the spread of rabies.
Analysis of the outbreak of rabies in 2007 showed that the trend of rabies prevalence in China continued to rise and spread from the south to the north, from high to low hair areas, with more cases in summer and autumn, more males than women. In seven provinces of different rabies prevalence, 382 tissues from different host animals were collected and direct immunofluorescence was used. 81 specimens of rabies virus infection were detected by two methods of light and RT-PCR, and 720 (634-1353) nucleotide sequences of the N gene coding region were amplified and sequenced, and 34 nucleotide sequences of the virus specimens were obtained. The homology analysis results of the gene sequence: the nucleotide sequence of 34 N genes was 87.5-100%, The deduced amino acid sequence homology is 93.3-99.6%, which indicates that the variation of the nucleotide sequence of the region is mainly synonymous mutation.N protein. The amino acid sequence of the section contains I, III, IV antigen sites and Th cell epitopes, and these functional sites of the 34 virus specimens are highly conserved, and there are 389 silk ammonia in the amino acid section. Acid phosphorylation sites and 375 threonine secondary phosphorylation sites suggest that the conservatism of N gene functional sites is related to the genetic stability of N gene.
The nucleotide sequence tree analysis of the N gene showed that all the 34 virus specimens belonged to the type I rabies virus, which had the regional characteristics of further evolution to different groups or subgroups according to the different source provinces, and there was mutual infection and transmission between wild animals and domestic animals. The possibility of spreading to the eastern region and the southeast region, which is consistent with the regional distribution and diffusion trend of rabies in recent years, shows that there is a direct relationship between the prevalence of rabies and the distribution and transmission of rabies virus in China. In comparison with international strains, all Chinese specimens (I, II, and group III) are concentrated in the analysis. A large branch shows that rabies virus in our country is different from other countries and circulates basically in the country and its surrounding areas. Under China's branch, there are 2 rabies viruses in two Asian countries, including Indonesia and Thailand, of which the Yunnan and Thailand isolates of group II are closely related to the Thailand canine isolates, with the other 3. The relationship of 3 native strains (I, III group) is relatively distant. According to the historical background and the analysis of many factors, the interaction and transmission of rabies virus may exist in Southeast Asia and China.
The results show that the epidemic situation of rabies in China continues to rise in recent years and presents regional diffusion. The spread and diffusion of rabies virus may be one of the reasons for the rapid increase of the epidemic situation and the expansion of the epidemic area. The nucleotide variation of the N gene of rabies virus in our country presents regional characteristics and the antigen loci on the encoded protein are highly conservative. The N gene phylogenetic tree analysis showed that all of these regions were prevalent in the region of type I rabies virus, and the virus derived from the same province showed higher genetic characteristics. The evolutionary relationship of the virus specimens and the epidemiological background showed that between Chinese wild animals and domestic animals, between domestic animals and neighbouring animals, may be possible. The cross infection and transmission of rabies virus are present.
In this study, the N gene characteristics of wild and domestic rabies virus epidemic strains in different areas of China's rabies epidemic were analyzed in detail. The characteristics of the genetic variation of rabies virus in China and the relationship with the epidemic were discussed in order to make the prevention and control measures of rabies in our country more scientifically. Provide scientific basis for application.

【学位授予单位】：中国疾病预防控制中心
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R512.99;R181.3

【引证文献】