内蒙古林区媒介蜱携带病原体的调查研究

发布时间：2018-05-26 11:26

本文选题：蜱媒传染病 + 伯氏疏螺旋体　；参考：《中国人民解放军军事医学科学院》2017年硕士论文

【摘要】：一.研究背景蜱媒传染病(Tick-borne infectious diseases)是一类由媒介蜱传播、感染所引发的自然疫源性疾病。蜱携带和传播的病原体种类数量繁多(包括病毒、细菌、立克次体、螺旋体等)、宿主动物分布广泛、流行环节复杂交错,且易受到自然环境和社会经济条件的影响,几种蜱传疾病往往共存于同一疫源地,一种媒介蜱也可同时携带两种或两种以上的病原体,这极大的增加了宿主动物及人类复合感染的机率,极易造成蜱传疾病的流行和暴发。自1982年以来,我国已发现33种新发蜱媒传染病病原体[1-7],包括3种无形体(Anaplasma)、3种埃里克体(Ehrlichia)、8种斑点热群立克次体(spotted fever group rickettsiae,SFGR)、6种伯氏疏螺旋体(Borrelia burgdorferi sensu lato)、11种巴贝西虫(Babesia)及发热伴血小板减少综合征病毒(severe fever with thrombocytopenia syndrome virus,SFTSV),其中15种新发蜱传病原体可以导致人类感染(新发蜱媒传染病第一时间被确认的地点和时间,附录1[82])。莱姆病(Lyme disease,LD)是20世纪70年代发现的由伯氏疏螺旋体(Borrelia burgdorferi sensu lato,Bb)引起的一种蜱媒传染病。现报告已有70多个国家和地区存在本病或自然疫源地,在美国莱姆病又被称作“第二艾滋病”,世界卫生组织已将其列为需要重点进行研究和防治的新发传染病。我国自1986年发现莱姆病自然疫源地以来,通过病原学检测已证实有19个省、市和自治区存在莱姆病的自然疫源地,9种蜱可携带和传播伯氏疏螺旋体,8种野鼠、狗、牛、羊和野兔体内存在自然感染。近年来,我国莱姆病患者每年都有上万余例报道,其危害性和严重性日益受到人们关注。斑点热是由立克次体属(Rickettsia)的斑点热群立克次体(spotted fever group Rickettsiae,SFGR)引起的一类以急性发热和全身皮疹为主要特征的疾病总称。SFGR是立克次体目中最大最复杂的一个群种,是一种全球性分布、严格血管内皮细胞寄生的小杆菌,革兰氏染色阴性,到目前为止能引起人类感染的SFGR至少19种。我国已在10多个省、市、自治区证实有SFGR感染,并且发病地区及范围不断扩大和变迁。近年来,新种SFGR及其所引致的斑点热在我国和世界各地不断发现和报道。内蒙大兴安岭林区自然资源丰富,生态系统物种多样,并以其独特的地理优势和自然景观适宜蜱类栖息,是我国蜱媒传染病主要疫区之一[8],随着林区天然林保护工程实施和产业结构调整,林下资源开发逐渐增多,森林采伐量逐年减少,带动当地经济不断发展的同时,林区旅游业也迅速升温。随着进入林区人群的增加,人们被蜱虫叮咬、感染的机率就不断增多,发病率也越来越来高。因此,蜱媒传染病对在内蒙古林区从事经济开发、野外生产活动、旅游、野营、军事训练以及国防建设的人群威胁极大。二.研究目的通过本研究进一步了解我国内蒙古大兴安岭林区蜱中疏螺旋体和SFGR感染情况,补充和完善媒介蜱携带病原体的多样性和复杂性,为更好的防治蜱媒传染病提供可以借鉴的新思路。三.研究方法本研究选取内蒙古毕拉河林区(北纬N49°25′48.52″,东经E123°32′15.82″)、库都尔林区(北纬N50°01′35.64″,东经E121°36′58.73″)和奇乾林区(北纬N52°11′45.30″,东经E120°46′21.42″)为调查点,广泛采集全沟硬蜱(Ixodes persulcatus),森林革蜱(Dermacentor silvarum)和嗜群血蜱(Haemaphysalis conicinna)等多种蜱种,采用聚合酶链式反应(PCR)方法对疏螺旋体和SFGR感染及其基因分型进行研究。四.研究结果本研究我们在毕拉河、库都尔和奇乾三个林区共采集蜱标本792只,其中全沟硬蜱723只(91.29%)、森林革蜱48只(6.06%),嗜群血蜱21只(2.65%)。库都尔林区和奇乾林区均以全沟硬蜱为优势蜱种(c2=202.405,p=0.000),提示全沟硬蜱是该林区蜱媒传染病的主要传播媒介之一。PCR检测发现,蜱标本中疏螺旋体阳性携带率为35.35%,全沟硬蜱、森林革蜱、嗜群血蜱中携带疏螺旋体感染分别为276只(38.17%)、2只(4.17%)、2只(9.52%);基因分型结果显示有5种基因型别:B.garinii型,阳性蜱212只(阳性率26.77%);B.afzelii型,阳性蜱53只(阳性率6.69%);B.miyamotoi型,阳性蜱13只(阳性率1.64%);B.spielmanii型,阳性蜱1只(阳性率0.12%);Borrelia sp.NM517(B.sp.NM517)型,阳性蜱1只(阳性率为0.12%)。其中B.miyamotoi、B.spielmanii和B.sp.NM517三种基因型均为我国首次发现。经统计学分析表明B.garinii为我国大兴安岭林区莱姆病伯氏疏螺旋体优势基因型(c2=19.433,p=0.013)。另外,结果发现蜱标本中SFGR阳性携带率为40.4%,全沟硬蜱、森林革蜱、嗜群血蜱中SFGR感染分别为283只(39.14%)、28只(58.33%)、9只(42.86%),基因分型结果显示有3种基因型:新塔拉塞维奇立克次体(Candidatus Rickettsia tarasevichiae,CRT),阳性蜱284只(阳性率35.86%);劳氏立克次体(Rickettsia raoultii,R.raoultii),阳性蜱33只(阳性率4.17%);黑龙江立克次体(Rickettsiahelongjiangii,R.helongjiangii),阳性蜱3只(阳性率0.38%)。经统计学检验,内蒙古大兴安岭三个林区SFGR不同基因型阳性感染差异存在统计学意义(c2=82.474,p=0.000),库都尔林区和奇乾林区均以CRT为SFGR优势基因型,毕拉河林区以R.raoultii为优势基因型。经统计学分析显示,三个蜱种不同基因型SFGR的感染差异存在统计学意义(c2=251.838,p=0.000),全沟硬蜱和嗜群血蜱中CRT基因型为蜱携SFGR优势基因型,森林革蜱中R.raoultii为蜱携SFGR优势基因型。研究也发现媒介蜱存在疏螺旋体和SFGR的复合感染,复合感染率为14.52%(115只)。五.研究结论本研究结合现场调查、实验室检测,综合应用描述性和分析性流行病学等方法,对内蒙古大兴安岭林区媒介蜱中携带病原体的感染情况进行了深入调查,调查发现全沟硬蜱为当地优势蜱种。蜱中可单独或混合存在疏螺旋体(B.garinii型、B.afzelii型、B.miyamotoi、B.spielmanii、B.sp.NM517)和SFGR(CRT型、R.raoultii型、R.heilongjiangii型)感染。本研究首次在我国发现了疏螺旋体B.miyamotoi、B.spielmanii和B.sp.NM517三个基因型,其中B.miyamotoi属于疏螺旋体属中的回归热螺旋体,主要寄生在硬蜱中,常与B.afzelii、B.garinii等基因型在蜱中混合感染。B.spielmanii属于疏螺旋体属中的伯氏疏螺旋体,是新型人类致病性病原体。B.sp.NM517型序列同B.Theileri strain KAT 16s ribosomal RNA的序列相似度为98.77%,是一种新的基因型,但还未对其进行分离培养,这有待于进一步深入研究。本研究结果不仅为我国内蒙古大兴安岭林区媒介蜱携带病原体的多样性起到了补充和完善的作用,同时也可为更好的防治蜱媒传染病提供可以借鉴的新思路。
[Abstract]:Tick-borne infectious diseases is a natural epidemic disease caused by the transmission and infection of ticks. The number of pathogens carried and transmitted by ticks is numerous (including viruses, bacteria, Rickettsia, spirals, etc.), the host is widely distributed, the epidemic is complicated and interlaced, and is vulnerable to natural rings. Several tick borne diseases often coexist in the same source area, and a medium tick can also carry two or more than two pathogens at the same time, which greatly increases the probability of complex infection between host animals and human beings, which is very easy to cause the epidemic and outbreak of tick borne diseases. Since 1982, China has found 33 new types of new diseases. The tick borne infectious disease pathogen [1-7], including 3 kinds of intangibles (Anaplasma), 3 kinds of Eric body (Ehrlichia), 8 kinds of spotted fever group rickettsiae, SFGR, 6 kinds of Borrelia (Borrelia burgdorferi sensu lato), 11 kinds of BABEI and fever accompanied thrombocytopenia syndrome virus Th thrombocytopenia syndrome virus, SFTSV), of which 15 new tick borne pathogens can cause human infection (the location and time identified for the first time of the new tick infectious disease, appendix 1[82]). Lyme disease (Lyme disease, LD) was found in 1970s by a species of Borrelia burgdorferi (Borrelia burgdorferi sensu). Tick borne infectious diseases have been reported in more than 70 countries and regions. In the United States, Lyme disease is also known as "second AIDS". The WHO has listed it as a new infectious disease which needs to be studied and controlled. Since the discovery of the natural epidemic of Lyme disease in 1986, it has been tested by pathogeny. There are 19 provinces, cities and autonomous regions have natural foci of Lyme disease, 9 ticks can carry and spread Borrelia burgdorferi, 8 kinds of wild mice, dogs, cattle, sheep and rabbits have natural infection. In recent years, there are more than 10000 cases of Lyme disease patients in China each year, and their harmfulness and severity are increasingly concerned. Rickettsia (spotted fever group Rickettsiae, SFGR), a group of diseases characterized by acute fever and systemic rash, is the largest and most complex group in the rickettsia, a global distribution, microbacilli with strict vascular endothelial cells, and gram dye. Color negative, at least 19 species of SFGR can cause human infection so far. China has been in more than 10 provinces, municipalities and autonomous regions confirmed SFGR infection, and the area and scope of the disease has been expanding and changing. In recent years, new species of SFGR and its spotted fever have been found and reported in China and all over the world. Natural capital in the Greater Khingan Range forest area of Inner Mongolia. Rich in source and diversity of ecosystem species, and with its unique geographical advantage and natural landscape suitable for tick species, it is one of the main epidemic areas of tick borne diseases in China, [8]. With the implementation of the forest protection project and the adjustment of industrial structure, the development of the forest resources is gradually increasing, the forest harvesting is decreasing year by year, and the local economy is developing continuously. At the same time, the tourism industry in the forest area has also increased rapidly. As people enter the forest area, people are bitten by ticks, and the incidence of infection is increasing and the incidence is increasing. Therefore, tick borne infectious diseases are a great threat to people engaged in economic development, field production, tourism, camping, military training and national defense construction in the Inner Mongolia forest area. Two. The purpose of this study is to further understand the infection of sparsely spirals and SFGR in Greater Khingan Range forest ticks in Inner Mongolia, to supplement and improve the diversity and complexity of vector borne pathogens, and to provide new ideas for better prevention and control of tick borne infectious diseases. Three. The research method selected the Inner Mongolia Biira forest The area (north latitude N49 25 '48.52 ", east longitude E123 32' 15.82"), Qulu forest region (north latitude N50 / 01 '35.64 ", East Jing E121 36' 58.73") and Qi Qian forest region (north latitude N52 11 '45.30 "), E120 degree 46' 21.42") as investigation points, widely collect whole ditch Ixodes (Ixodes persulcatus), chlorpyrifos (Dermacentor silvarum) and eosinophilia (H) Aemaphysalis conicinna) and other ticks, using polymerase chain reaction (PCR) method to study the infection and genotyping of Treponema and SFGR. Four. We collected 792 tick specimens in three forest areas of the Biira River, koudar and Qi Qian, of which 723 (91.29%), 48 (6.06%), three (6.06%). 21 (2.65%) of the blood ticks (c2=202.405, p=0.000) in the coudine forest area and Qi Qian forest area, suggesting that the whole trench tick is one of the main vectors of the tick borne infectious disease in the forest area. The positive rate of the spiral body in the ticks is 35.35%, the whole furrow tick, the leeticos, and the eosinophilic tick carry the sparse helix. The body infection was 276 (38.17%), 2 (4.17%) and 2 (9.52%). The genotyping results showed that there were 5 genotypes: B.garinii type, 212 positive ticks (positive rate 26.77%); B.afzelii, positive ticks 53 (positive rate 6.69%); B.miyamotoi type, positive ticks 13 (positive rate 1.64%); B.spielmanii, positive ticks (positive rates); Borrelia sp.NM51 7 (B.sp.NM517) and 1 positive ticks (positive rate 0.12%). Among them, three genotypes of B.miyamotoi, B.spielmanii and B.sp.NM517 were found for the first time in China. The statistical analysis showed that B.garinii was the dominant genotype of Borrelia burgdorferi (c2= 19.433, p=0.013) in Greater Khingan Range forest region of China. In addition, it was found that SFGR positive was found in the ticks. The rate of SFGR was 40.4%, 283 (39.14%), 28 (58.33%) and 9 (42.86%) infected ticks of ticks, 28 (58.33%) and 9 (42.86%). The results of genotyping showed that new Tara Savage Ricketts Ti (Candidatus Rickettsia tarasevichiae, CRT), positive ticks 284 (positive rate 35.86%); Rickettsia Lloyd (Rickettsia Raoult). II, R.raoultii), 33 positive ticks (positive rate 4.17%); Heilongjiang rickettsia (Rickettsiahelongjiangii, R.helongjiangii), 3 positive ticks (positive rate 0.38%). By statistical test, the difference of positive infection of different genotypes of SFGR in three forest areas in Greater Khingan Range of Inner Mongolia was statistically significant (c2=82.474, p=0.000), and in the region of Hulu forest and Qi Qian forest area CRT was the dominant genotype of SFGR, and R.raoultii was the dominant genotype in the Biya river forest region. The statistical analysis showed that the difference of infection between three ticks of different genotypes was statistically significant (c2=251.838, p=0.000). The CRT genotypes of ticks and eosinophilic ticks were ticks carrying SFGR dominant genotypes, and R.raoultii was tick carrying SF. GR dominant genotypes. The study also found that the compound infection of Treponema and SFGR was found in the medium ticks, and the rate of compound infection was 14.52% (115). Five. Conclusion this study combined with field investigation, laboratory testing, comprehensive application of descriptive and analytical epidemiology to carry out the infection of pathogens in Greater Khingan Range forest area of Inner Mongolia. The survey found that the whole ditch was a local dominant tick. The ticks could be isolated or mixed in the ticks (B.garinii, B.afzelii, B.miyamotoi, B.spielmanii, B.sp.NM517) and SFGR (CRT, R.raoultii, R.heilongjiangii). This study was first found in our country for B.miyamotoi, B.spiel. Three genotypes of manii and B.sp.NM517, of which B.miyamotoi belongs to the regression heat spirals in the genus heliospira, mainly parasitic in ticks, often mixed with B.afzelii, B.garinii and other genotypes in ticks and.B.spielmanii belongs to burgospira Borrelia, a new human pathogenic pathogen.B.sp.NM517 sequence and B.Th. The sequence similarity of eileri strain KAT 16S ribosomal RNA is 98.77%, which is a new genotype, but it has not been isolated and cultured. It needs to be further studied. The results of this study not only complement and improve the diversity of the pathogen of the media ticks in the Greater Khingan Range forest area of Inner Mongolia, but also can be used as a result. Better prevention and treatment of tick borne infectious diseases can provide new ideas for reference.
【学位授予单位】：中国人民解放军军事医学科学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R181.3;R53

【参考文献】