我国内蒙古自治区流行性乙型脑炎流行病学分析

发布时间：2018-03-17 17:34

本文选题：内蒙古　切入点：流行性乙型脑炎　出处：《中国疾病预防控制中心》2009年硕士论文　论文类型：学位论文

【摘要】： 流行性乙型脑炎(乙脑)是感染乙脑病毒引起的急性传染性疾病,蚊虫为传播媒介。乙脑的病死率约为5-30%,幸存者约30-50%留有严重神经系统后遗症,给社会和家庭造成沉重负担。乙脑主要流行于亚洲和太平洋地区,我国是乙脑流行的主要国家之一。我国内蒙古自治区(内蒙古)曾是乙脑的高流行区,历史上曾发生多次爆发流行,近十年来乙脑病例明显减少。本研究收集了内蒙古1950-2007年乙脑病例资料进行分析,同时于2007和2008年在内蒙古东部、中部和西部连续两年采集蚊虫标本开展病原学调查,以期了解当地乙脑流行病学特征与乙脑及蚊传虫媒病毒的流行情况,结果报告如下。一、1950-2007年内蒙古乙脑流行病学特征分析本研究采用描述流行病学方法,系统分析了内蒙古自治区1950-2007年乙脑流行病学特征,结果显示: (1) 1950-2007年间内蒙古共报告乙脑4850例,历史上发生多次爆发流行,其中1974年乙脑发病率和死亡率为最高,分别为9.66/10万和1.51/10万; (2)根据历年乙脑发病的高低可将内蒙古乙脑的流行划分为三个时期:1950-1968年、1969-1984年和1985-2007年。1950-1968年间乙脑平均发病率为0.07/10万,1969-1984年间乙脑多次爆发流行,平均发病率为1.55/10万,1985-2007年间乙脑平均发病率为0.08/10万。1990年至2007年内蒙古乙脑发病率均低于全国同期乙脑发病率水平; (3) 1950-2007年间内蒙古12个盟市中的10个盟市有乙脑病例报告,乌海市和阿拉善盟从未有乙脑病例报告。报告病例较多的地区为赤峰市和通辽市,占内蒙古乙脑总例数84.8%。赤峰市和通辽市的报告病例主要集中在1969-1984年; (4)内蒙古乙脑发病具有明显的季节特征,每年7月发病人数开始上升,病例主要集中在每年8、9月,10月病例显著下降。与全国和南方的贵州省相比,内蒙古乙脑发病高峰季节错后1个月(全国和贵州7、8月为高发期);与我国北方宁夏回族自治区的乙脑发病高峰季节相似,均为8、9月份; (5) 1988-2007年间乙脑发病人群性别、年龄分析特征如下:1988-2007年间乙脑报告病例中男女性别比为1:0.48,男性明显多于女性;各年龄组均有乙脑病例报告,其中15岁以下儿童占发病总数28.61%,明显低于全国平均水平(88.03%); (6) 1991-2007年间乙脑病例职业分布以农民(47.71%)、学生(23.85%)和散居儿童(8.72%)为主,而全国乙脑病例职业分布以散居儿童(51.7%)、学生(26.2%)和托幼儿童(10.9%)为主。二、内蒙古乙脑及蚊传虫媒病毒病原学调查为了解内蒙古乙脑病毒及蚊传虫媒病毒的分布情况,我们选择内蒙古东、中、西部4个标本采集地连续两年开展蚊虫媒介和蚊传虫媒病毒的调查。 1、蚊虫媒介调查 2007和2008年7-8月在内蒙古通辽市、巴彦淖尔市、呼和浩特市和乌海市的11个旗县采集蚊虫标本,共采集到蚊虫3属7种共10542只。蚊种包括库蚊属凶小库蚊、淡色库蚊,伊蚊属刺扰伊蚊、背点伊蚊、里海伊蚊、黄背伊蚊和按蚊属中华按蚊。各地的优势蚊种有所差别,通辽市以背点伊蚊为优势蚊种,巴彦淖尔市以里海伊蚊为优势蚊种,呼和浩特市凶小库蚊与背点伊蚊为优势蚊种,乌海市以黄背伊蚊为优势蚊种。两年采集时间内均未采集到乙脑病毒的主要传播媒介三带喙库蚊。 2、病毒的分离与鉴定全部蚊虫标本按每批25～100只经过研磨,离心后,接种组织培养细胞(C6/36和BHK-21细胞)进行病毒分离。在呼和浩特市的凶小库蚊、背点伊蚊,通辽市凶小库蚊和巴彦淖尔市里海伊蚊中共分离到6株可以引起细胞病变的阳性病毒分离物。病毒分离物通过血清学(ELISA试验、间接免疫荧光试验),分子生物学(聚丙烯酰胺凝胶电泳试验、Real-time PCR试验和RT-PCR等)和生物信息学等方法的研究,结果显示2株病毒为布尼亚病毒科的Tahyna病毒,这是继我国首次(2006年)在新疆分离到Tahyna病毒后,再次分离到该病毒;1株病毒分离物为呼肠孤病毒科的版纳病毒,这是首次在内蒙古地区蚊虫中分离到版纳病毒;3株病毒分离物为细小病毒科Brevidensovirus属的淡色库蚊浓核病毒(Culexpipiens pallens Densovirus),这是在内蒙古首次从蚊虫中分离到该病毒。阳性分离物中未鉴定出乙脑病毒。三、其它工作本研究还于2008年在辽宁省锦州和丹东市开展了蚊虫和蚊传虫媒病毒调查。在辽宁省锦州市和丹东市共采集蚊虫标本,采集到蚊虫3属5种共9296只。蚊种包括库蚊属三带喙库蚊、淡色库蚊;伊蚊属背点伊蚊、刺扰伊蚊和按蚊属中华按蚊。丹东东港市以三带喙库蚊为优势蚊种,锦州北宁市以中华按蚊为优势蚊种。在丹东采集的三带喙库蚊和锦州的中华按蚊标本中获得4株病毒分离物,经过血清学和分子生物学试验鉴定为1株乙脑病毒,2株版纳病毒,1株为版纳病毒和辽宁病毒的混合株。新分离乙脑病毒全基因组序列进化分析显示,2008年在丹东蚊虫中分离的乙脑病毒与2002年和2007年在该地分离的病毒同属于基因Ⅰ型乙脑病毒,表明辽宁省丹东市持续存在基因Ⅰ型乙脑病毒。2008年乙脑病毒分离株与乙脑疫苗株(SA14-14-2株)病毒在E蛋白基因区段相比,决定病毒毒力和抗原性的关键氨基酸位点没有变化。小结本研究对内蒙古1950-2007年乙脑报告病例的流行病学资料进行了描述性分析,探讨了当地乙脑发病的流行病学特征,内蒙古乙脑病例主要集中在赤峰市和通辽市,发病季节高峰为8、9月,发病人群以农民、学生、散居儿童为主。这些数据为当地有效预防控制乙脑的流行提供了科学依据。本研究对内蒙古4个盟市进行了连续两年的虫媒病毒病原学调查,首次在内蒙古蚊虫标本分离到Tahyna病毒、版纳病毒和淡色库蚊浓核病毒。本调查结果揭示了当地蚊传虫媒病毒的多样性,提示当地可能存在布尼亚病毒科病毒感染等,应加强对当地虫媒病毒病检测与监测。
[Abstract]:Japanese encephalitis (JE) is an acute infectious disease caused by Japanese encephalitis virus infection, mosquito media. The mortality of JE is about 5-30%, about 30-50% of survivors have serious neurological sequelae, causing heavy burden to society and family. JE is popular mainly in the Asia Pacific region, China is one of the major countries of JE popular.
China the Inner Mongolia Autonomous Region (Inner Mongolia) was a high prevalence of JE, outbreaks had occurred repeatedly in the history, nearly ten years of Japanese encephalitis were significantly reduced. This study collected 1950-2007 years of Inner Mongolia JE cases were analyzed, at the same time in 2007 and 2008 in the eastern part of Inner Mongolia, central and Western mosquito samples were collected for two consecutive years to carry out the pathogen the investigation, in order to understand the prevalence and epidemiological characteristics of Japanese encephalitis and local JE mosquito borne virus, results are reported.
Analysis of epidemiological characteristics of encephalitis B in Inner Mongolia in the first and 1950-2007 years
In this study, descriptive epidemiological methods were used to systematically analyze the epidemiological characteristics of the 1950-2007 years in the Inner Mongolia Autonomous Region. The results showed that:
(1) in the 1950-2007 years, a total of 4850 cases of JE were reported in Inner Mongolia in the past 1950-2007 years. There were many outbreaks in history. In 1974, the incidence and mortality of encephalitis B were the highest, which were 9.66/10 Vanward and ten thousand, respectively.
(2) according to the level of the incidence of Japanese encephalitis can be popular in Inner Mongolia is divided into three periods: the Japanese for 1950-1968 years, 1969-1984 years and 1985-2007 years.1950-1968 years average JE incidence rate of 0.07/10 million, 1969-1984 years of Japanese encephalitis several outbreaks, the average incidence rate was 100 thousand 1.55/, average 1985-2007 years of JE incidence rate of 0.08/10 million.1990 to 2007 Inner Mongolia JE incidence were lower than in the same period the incidence rate of je;
(3) 10 cities in 12 cities of Inner Mongolia 1950-2007 years of Japanese encephalitis case report, Wuhai and Alashan have reported cases of JE cases report. More area for Chifeng city and Tongliao City, Inner Mongolia accounted for the total number of cases of JE 84.8%. Chifeng city and Tongliao City reported cases are mainly concentrated in 1969-1984 years;
(4) the incidence of Japanese encephalitis in Inner Mongolia has obvious seasonal characteristics, the incidence in July began to rise, the cases were mainly concentrated in 8,9 months each year, October was significantly decreased. Compared with the whole country and the southern province of Guizhou, Inner Mongolia for 1 months the incidence peak season after the fault (national and Guizhou 7,8 month period); similar the Ningxia Hui Autonomous Region North China the incidence peak season was 8,9 months;
(5) sex 1988-2007 years JE incidence, age gender analysis features are as follows: 1988-2007 years of reported cases of JE than for the 1:0.48, there were more males than females; the various age group JE case report, including children under the age of 15 accounted for 28.61%, significantly lower than the national average level (88.03%);
(6) 1991-2007 JE cases in the occupation of farmers (47.71%), students (23.85%) and children (8.72%), and the national occupation in the distribution of JE cases scattered children (51.7%), (26.2%) students and kindergarten children (10.9%).
Two, investigation of Inner Mongolia encephalitis and mosquito borne arbovirus etiology
In order to understand the distribution of Inner Mongolia encephalitis virus and mosquito borne virus, we choose Inner Mongolia East, west 4 specimen collection for two consecutive years to carry out mosquito and mosquito borne arbovirus survey.
1, mosquito vector survey
In 2007 and 2008 7-8 months in Inner Mongolia, Tongliao City, Bayannaoer City, Hohhot city and Wuhai city 11 counties of mosquitoes were collected, were collected from 3 genera and 7 species of mosquitoes. A total of 10542 mosquito species including Culex cx.modestus, Culex pipiens pallens, Aedes ae.vexans, Aedes dorsalis, hay in mosquitoes. Yellow back Aedes and Anopheles sinensis. The dominant species vary across the Tongliao city to ae.dorsalis were the dominant species in the Caspian Sea, Bayannaoer city was the predominant species of Aedes, Hohhot cx.modestus and ae.dorsalis were the dominant species in Wuhai City, yellow back Aedes aegypti were dominant species. Two years the acquisition time were not collected in the main media of Japanese encephalitis virus three Culex.
2, isolation and identification of virus
All the mosquitoes collected according to each batch of 25~100 after grinding, after centrifugation, inoculated into tissue culture cells (C6/36 cells and BHK-21 cells) were isolated. In the city of Hohhot cx.modestus, ae.dorsalis cx.modestus, Tongliao city and Bayannaoer City, the isolated 6 strains of Aedes mosquitoes can cause positive virus cytopathic isolates. Virus isolates by serological (ELISA test, indirect immunofluorescence test), molecular biology (polyacrylamide gel electrophoresis test, Real-time PCR test and RT-PCR) research and bioinformatics method, the results showed that Tahyna virus strain 2 virus of Bunyaviridae, this is the first time in China (2006) in Xinjiang isolation of Tahyna virus, the virus isolated again; 1 strains of the virus isolate reovirus of Banna virus, which was first isolated in the Inner Mongolia area of Banna virus in mosquitoes; 3 strains The virus isolate is Culexpipiens pallens Densovirus of the genus Brevidensovirus of the parvovirus family. It was first isolated from mosquitoes in Inner Mongolia.
Three, other work
This study also on 2008 in Liaoning, Jinzhou province and Dandong city to carry out the investigation of mosquito and mosquito borne arbovirus. Mosquitoes were collected from Jinzhou city in Liaoning province and Dandong City, 3 genera and 5 species of mosquitoes collected a total of 9296 species including three. Culex mosquitoes, Culex pipiens pallens; Aedes genus Aedes dorsalis. Aedes vexans and Anopheles sinensis in Dandong city of Donggang in three. Culex tritaeniorhynchus was the dominant species in Jinzhou, Beining City Anopheles sinensis was the dominant species. 4 strains of the virus was collected in Dandong three Culex and Anopheles sinensis in Jinzhou isolates by serological and molecular biological test for 1 Japanese encephalitis virus strains, 2 strains of Banna virus, 1 strains of Banna virus and Liaoning virus. Mixed strains of Japanese encephalitis virus isolated from whole genome sequence evolution analysis showed that in 2008 in Dandong in the separation of Japanese encephalitis virus and mosquito in 2002 and 2007 in the separation The virus belonged to the genotype of Japanese encephalitis virus, Liaoning city of Dandong province showed that persistent strains and JE vaccine strains isolated JEV.2008 of Japanese encephalitis virus (SA14-14-2 strain) virus was compared in E gene segment, key amino acids to determine the virulence and antigenicity of no change.
Summary
Epidemiological data of Inner Mongolia 1950-2007 years of JE cases in this study were descriptive analysis, discusses the epidemiological characteristics of local incidence, Inner Mongolia JE cases were mainly concentrated in Chifeng city and Tongliao City, the peak seasons for 8,9 months, the incidence in farmers, students, scattered children. These data provide a scientific basis for the local effective prevention and control of JE epidemic.
The study of 4 cities of Inner Mongolia for two consecutive years of investigation of arbovirus pathogens, Tahyna virus was first isolated in Inner Mongolia mosquito specimens, Banna virus and culexpipienspailensdensovirus. The results revealed the diversity of local mosquito borne virus, suggesting possible Bunyaviridae infection, should strengthen the the detection and monitoring of local arbovirus diseases.

【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】：2009
【分类号】：R181.3;R512.32

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