黑龙江口岸蜱类及其携带病原体状况的初步研究

〔目的〕从分子流行病学角度探讨可能存在的新发蜱媒传染病及复合感染情况。〔方法〕采集黑龙江10个口岸的蜱类,通过病原培养分离,动物试验后进行分子生物学检测。〔结果〕检出4种病原微生物,发现了复合感染蜱,其中,人巴贝西原虫为国内首次检出,人埃立克体为质检系统内首次检出。全沟硬蜱可同时携带这4种病原体。〔结论〕黑龙江口岸蜱类及蜱携带病原体情况复杂,引起蜱传疾病的风险巨大。     

黑龙江口岸蜱类斑点热群立克次体感染状况初探

〔目的〕对黑龙江口岸蜱类感染斑点热群立克次体的状况进行调查,为口岸病媒防制工作提供科学依据。〔方法〕对黑龙江10个口岸蜱类进行采集,并通过病原培养分离,动物试验后进行分子生物学检测。〔结果〕在黑龙江口岸采集的蜱类样本中检出斑点热群立克次体,以全沟硬蜱的感染率最高。〔结论〕中俄边境口岸蜱类携带病原体具有复杂性。本次研究为控制中俄边境口岸发生蜱传斑点热疫情提供了预防控制依据。     

黑龙江口岸蜱携带斑点热群立克次体及嗜吞噬细胞无形体复合感染调查

目的为了研究黑龙江地区密山、绥芬河、嘉荫、东宁、虎林、同江、逊克、萝北、牡丹江、黑河、饶河11口岸蜱类分布、携带及复合感染新发蜱传病原体的情况。方法 2014年4月到2015年10月,利用布旗法采集蜱类样本,通过建立斑点热群立克次体(spotted fever group Rickettsia,SFGR)及嗜吞噬细胞无形体(Anaplasma phagocytophilum,A.P.)特异性引物,利用PCR方法对所有样本进行特异性片段扩增,通过基因测序对五种新发蜱传疾病作进一步鉴定并分型。结果共采集1306只蜱标本,经分类鉴定分属于革蜱属的森林革蜱、硬蜱属的全沟硬蜱和血蜱属的嗜群血蜱和日本血蜱。共检测出528例(40.43%)斑点热群立克次体阳性样本和31例(2.37%)嗜吞噬细胞无形体阳性样本。并证实存在三种斑点热群立克次体,分别为劳氏立克次体Rickettsia raoultii、新塔拉塞维奇立克次体Candidatus Rickettsia tarasevichiae、黑龙江立克次体Rickettsia heilongjiangensis。共检测到复合感染12例,复合感染率为0.92%(12/1306)。结论黑龙江口岸媒介蜱类存在斑点热群立克次体及嗜吞噬细胞无形体的复合感染现象,提示黑龙江地区蜱媒疾病的危险程度很高,急需加强黑龙江口岸地区蜱媒传染病及其复合感染的监测与防控技术研究,进而建立科学合理的新发蜱媒疾病预警监测和防控技术体系。     

黑龙江中俄边境口岸全沟硬蜱中分离到人巴贝西原虫

〔目的〕了解中俄边境口岸人巴贝西原虫在蜱体内的感染携带情况及病原基因特征,以便采取必要的防控措施。〔方法〕用从黑龙江中俄边境口岸采集到的全沟硬蜱叮咬清洁级的SCID小鼠,而后,利用微气固相分离技术从被叮咬的SCID小鼠中分离人巴贝西原虫。〔结果〕涂片观察可见血细胞内呈现典型的四分体和环状体。离体培养血细胞中亦观察到人巴贝西原虫的生长。核糖体小亚基的基因序列分析表明,新分离到的人巴贝西原虫是微小巴贝西原虫,与密山株和日本神户株具有高度同源性。本批样本中,雌性全沟硬蜱的感染率为2.7%～4.0%。〔结论〕中俄边境口岸存在人巴贝西原虫的自然疫源地,存在人感染的风险,检验检疫部门应采取必要的防范措施,防止巴贝西原虫病传入传出。     

浙江省建德市蜱媒传染病综合监测研究

目的 了解建德地区蜱媒传染病主要宿主和媒介的种群密度、季节消长、染带关系和病原体携带状况,为蜱媒传染病预防控制提供科学依据。方法 采用布旗法、宿主动物体表检蜱法采集蜱,用鼠笼捕捉鼠形动物,采用PCR方法检测其蜱媒传染病感染情况。结果 建德地区主要蜱种有长角血蜱、中华硬蜱和镰形扇头蜱,长角血蜱为优势种,布旗法6月蜱密度最高,体表检蜱法6月带蜱率最高。在蜱及宿主动物中检出嗜吞噬细胞无形体、巴贝西原虫、查菲埃立克体、立克次体、巴尔通体、肾综合征出血热病毒6种蜱媒传染病病原体,并存在病原体复合感染。结论 建德地区蜱媒传染病的宿主和媒介广泛分布,而且携带多种病原体,需要采取措施进行防制。     

国境口岸输入性蚊类防控措施的探讨

〔目的〕探讨我国国境口岸防控输入性蚊类的措施,为口岸卫生检疫工作提供技术支持。〔方法〕收集我国国境口岸输入性蚊类监测结果与携带病原体检测研究情况以及防控输入性蚊类的法律政策规定情况并进行总结分析。〔结果〕结合口岸卫生检疫工作需要,提出了我国口岸今后有效防止输入性蚊类及蚊媒传染病自境外传入应采取的主要控制措施。〔结论〕为保障口岸卫生安全,今后应切实加强我国国境口岸输入性蚊类的防控工作力度。     

内蒙古部分边境口岸地区主要蜱类及蜱媒病原检测

目的 调查内蒙古主要陆地边境口岸地区蜱的种群分布、构成和自然感染病原体情况.方法 采用人工/小时布旗法和宿主体上搜法采集蜱标本,PCR法进行病原检测.结果 在被调查的策克、满都拉、满洲里3个口岸地区共采集蜱1313只,隶属于1科4属7种.草原革蜱在3个口岸均有分布,策克口岸获蜱占69.08%、蜱种多(6种)、短小扇头蜱为该口岸的优势种占74.86%.3个口岸地区共检测出5种蜱传疾病病原体,其中贝氏斯柯氏体仅在策克检出;平均感染率依次为莱姆病螺旋体15.08%、人巴贝西原虫3.35%、斑点热群立克次体1.98%、贝氏斯柯氏体1.07%、埃立克体0.99%.蜱感染莱姆病螺旋体阳性率在上述3个口岸地区均较高,分别为13.56%、22.88%、5.00%,且地区间差异有统计学意义;人巴贝两原虫、斑点热群立克次体地区间阳性率差异有统计学意义.结论 莱姆病螺旋体等5种蜱媒病原在策克、满都拉、满洲里口岸地区有不同程度自然感染.     

浙江口岸2005～2006年鼠形动物及体表寄生虫调查

〔目的〕掌握浙江各口岸(宁波除外)鼠形动物的种群构成、季节消长、体表寄生虫(蜱、蚤、螨)携带情况和鼠血清携带病原体(出血热抗原抗体和鼠疫抗体)情况,做好口岸鼠类监测工作,为口岸灭鼠提供科学依据。〔方法〕统一采用ELTON夹日法,每月中旬连续3d,连续12个月。〔结果〕本次调查共捕获各类鼠形动物585只,隶属于2目2科4属7种,蜱102只、蚤34只、螨353只,鼠密度为1.67%,出血热抗体检测506份,阳性标本22份,抗原检测22份,阳性标本8份;鼠疫抗体检测220份,全部为阴性。〔结论〕浙江局口岸鼠密度较高,离无鼠害口岸的标准(<1%)有较大的差距,今后应大力开展防鼠灭鼠工作,加强鼠密度监测,有效地控制口岸鼠密度,以期能达到国家无鼠害口岸的标准。     

内蒙古地区2015—2019年不同寄生蜱的种群分布及病原体多样性分析

目的 了解内蒙古地区2015—2019年不同寄生宿主蜱的蜱种分布、病原体感染及复合感染状况。方法 在每年蜱活跃高峰期采集蜱标本,经体视显微镜和特异性18S rRNA基因分型法进行蜱种鉴定。提取蜱基因组DNA,并对斑点热立克次体gltA和rOmpA基因、无形体msp2基因、埃立克体omp1基因、莱姆病螺旋体flaB基因和新型回归热螺旋体glpQ基因等病原体进行PCR检测。结果 本次共采集蜱虫6 465只,隶属于1科5属8种。游离蜱多为全沟硬蜱（79.0%）;羊和牛寄生蜱多为草原革蜱（68.2%,52.0%）;马和骆驼寄生蜱均为亚洲璃眼蜱;犬寄生蜱均为图兰扇头蜱。立克次体gltA阳性率为39.4%,其中羊、骆驼、马、牛等家畜寄生蜱阳性率均超过平均值;其他4种病原体多为游离蜱携带,其阳性率分别为12.3%、10.1%、11.0%、17.0%。内蒙古地区蜱媒疾病复合感染率为12.6%,其中,游离蜱复合感染率高于寄生蜱。结论 家畜感染立克次体较严重。游离蜱的复合感染情况较严重,因此要重点加强东部大兴安岭一带蜱媒传染病的监测工作。     

福建长乐辖区口岸鼠形动物及体表寄生虫调查

〔目的〕掌握福建长乐辖区口岸各开放码头鼠形动物的种群构成、季节消长、体表寄生虫(蚤、蜱、螨)携带情况和鼠肝、脾、肺组织携带病原体(鼠疫F1抗原抗体和流行性出血热病毒核酸)检测情况,为口岸鼠类监测及防治提供科学依据。〔方法〕统一采用标准捕鼠笼法,每月上下旬各监测1次,连续12个月。〔结果〕本次调查共捕获各类鼠形动物756只,经鉴定隶属于2目2科4属7种;蚤61只、蜱13只、革螨85只、恙螨455只,鼠密度为6.73%。取鼠肺及肝、脾324份,检测鼠流行性出血热汉坦病毒核酸及鼠疫抗原抗体检测,其中133份血清标本进行鼠疫F1抗原抗体检测结果全部阴性。〔结论〕长乐辖区口岸鼠密度较高,离国家规定的口岸3%控制标准有较大差距,今后要进一步开展鼠形动物监测和防鼠灭鼠工作,有效地控制鼠密度,以期达到不足为害的程度。     

黑龙江省11个边境口岸蜱类调查

〔目的〕调查黑龙江省11个边境口岸蜱的种群组成。〔方法〕采用人工小时布旗法采集蜱。〔结果〕在黑龙江省11个边境口岸采获蜱3926只,计3属4种。林缘的优势种群为森林革蜱(95.9%);针阔混交林为全沟硬蜱(46.1%)和森林革蜱(31.8%)。不同口岸的蜱种组成有所不同。绥芬河口岸蜱密度指数最高(93.1%只/人工小时)。不同生境蜱密度指数有所不同。4种蜱的雌雄比:日本血蜱2.7:1,森林革蜱1.7:1,嗜群血蜱1.3:1,全沟硬蜱1.1:1。〔结论〕本次调查为黑龙江省边境口岸地区的蜱种群组成研究提供了依据。     

Circulation of four species of Anaplasmataceae bacteria in ticks in Harbin,northeastern China

Ticks play an important role in the evolution and transmission of Anaplasmataceae bacteria which are agents of emerging infectious diseases. In this study, a total of 1286 adult ticks belonging to five species were collected from cattle, goats, horses and vegetation in Harbin area, Heilongjiang province, northeastern China. The tick-borne Anaplasmataceae bacteria were identified by amplifying and sequencing the 16S rRNA (rrs) and heat shock protein-60 encoding (groEL) genes. The results showed that Ixodes persulcatus was dominant (38.8%, 499/1283) among the five tick species, and Anaplasmataceae bacteria were detected in all tick species with an overall prevalence of 7.4%. Four species of Anaplasmataceae bacteria (Anaplasma phagocytophilum, Anaplasma ovis, Anaplasma bovis, and “Candidatus Neoehrlichia mikurensis”), which are pathogenic to humans and/or animals, were identified from tick samples by phylogenetic analyzes of the rrs and groEL gene sequences. Interestingly, the cluster 1 strains were first identified in Asian, and a novel cluster was also detected in this study. These data revealed the genetic diversity of Anaplasmataceae bacteria circulating in ticks in Harbin area, highlighting the need to investigate these tick-borne pathogens and their risks to human and animal health.     

Ecological relationships between ticks and rickettsiae

Ticks play important roles as vectors and sometimes as reservoirs in the ecology of rickettsiae. The obligate association between ticks and rickettsiae has been elucidated in studies concerning the maintenance of rickettsiae in ticks, agent dissemination in various tick organs, rickettsial developmental cycles in the tick organism, transfer among various developmental stages in tick hosts, the effect of rickettsiae on the tick organism, the interaction between microorganisms other than rickettsiae and rickettsiae is a tick body, as well as the release of rickettsiae from ticks into the environment.Presented at the 4th European Congress of Clinical Microbiology, Nice, 177-20 April, 1989.     

多聚酶链反应技术在斑点热群立克次体流行病学调查中的应用

作者首次用来自立氏立克次体（Ｒ．ｒｉｃｋｅｔｔｓｉｉ，Ｒｒ）１９０ＫＤａ蛋白抗原基因序列设计的一对引物扩增从黑龙江、河北、海南、北京采集的蜱、蜱卵、幼蜱、蜱粪及啮齿动物脏器中斑点热群立克次体ＤＮＡ。结果从上述标本中均检测出了斑点热群立克次特异的５３２ｂｐ大小的ＤＮＡ片段，该结果部分与同期进行的病原分离结果一致。故认为，ＰＣＲ技术是一种快速、敏感、特异的斑点热群立克次体流行病学调查方法。     

Bartonella spp. Transmission by Ticks Not Established

Bartonella spp. infect humans and many animal species. Mainly because PCR studies have demonstrated Bartonella DNA in ticks, some healthcare providers believe that these microorganisms are transmitted by ticks. B. henselae, in particular, is regarded as being present in and transmissible by the Ixodes scapularis tick. The presence of a microbial agent within a tick, however, does not imply that the tick might transmit it during the course of blood feeding and does not confer epidemiologic importance. After a critical review of the evidence for and against tick transmission, we conclude that transmission of any Bartonella spp. by ticks, to animals or humans, has not been established. We are unaware of any well-documented case of B. henselae transmission by I. scapularis ticks.     

Small risk of developing Lyme borreliosis following a tick bite on Ameland: research in a general practice

OBJECTIVE: To investigate the percentage of ticks infected with Borrelia burgdorferi on the Dutch North Sea island of Ameland, and the risk of developing Lyme disease following tick bite on the island. DESIGN: Prospective, observational. METHOD: Ticks were collected from patients who visited a general practitioner and were tested for the DNA of B. burgdorferi. After 6 months the patients were interviewed by phone using a standardised questionnaire. RESULTS: From 2004-2006, 216 ticks were collected from 167 persons. Most ticks were removed within 24 hours. In 44 ticks (20.4%) B. burgdorferi DNA was detected. Follow up information was available on 146 persons, 41 (28.1%) of whom had been bitten by a Borrelia-positive tick. None of the persons developed a typical erythema migrans. From the 13 persons (9%) reporting a non-specific redness of the skin (diameter less than 5 cm) at the site of the tick bite, 5 had been bitten by a positive tick and 8 by a negative tick. One patient bitten by a positive tick reported systemic symptoms related to Lyme borreliosis, namely fatigue, perspiration and joint ache, without local redness. CONCLUSION: The probability of developing Lyme borreliosis was low even though a relatively large percentage of the ticks collected were positive for B. burgdorferi. This is probably connected to the fact that in the majority of cases the tick had been removed within 24 hours.     

Immature hard ticks infected with Rickettsia amblyommatis on breeding birds from Pantanal

Immature hard ticks from the genus Amblyomma feed on blood from a wide range of Neotropical avian hosts. They serve as vectors for pathogens of medical and veterinary importance, such as Rickettsia agents of the spotted fever group (SFG). Hence, determining ecological factors that increase encounter rates between immature ticks and their avian hosts may contribute to the understanding of tick-borne diseases transmission. Here, we used 720 individual birds from 96 species surveyed in the Brazilian Pantanal to test whether host breeding season influenced tick infestation probabilities. Additionally, collected ticks were screened for Rickettsia agents to describe new avian-tick-bacteria associations. Our models revealed that the probability of an individual bird being infested with immature ticks was similar during the breeding and pre-breeding season, but higher loads of immature tick stages were found during the breeding season. Host sex did not predict infestation probability, but Rickettsia agents recovered from ticks were more prevalent during the pre-breeding season. The new records of host usage by larvae and nymphs of Amblyomma in Pantanal and the growing body of tick surveys in Neotropical avian communities, suggest that immature ticks may benefit from avian blood sources during their annual cycle. The low number of infected ticks with Rickettsia agents on Pantanal birds suggest that this vertebrate group are likely not acting as reservoirs for these microorganisms. However, long-term surveys at the same site are imperative to determine which tick species are acting as reservoirs for Rickettsia agents in Pantanal and determine whether birds are playing a role in dispersing ticks and tick-borne pathogens.     

Microclimate conditions alter Ixodes scapularis (Acari: Ixodidae) overwinter survival across climate gradients in Maine,United States

The incidence and geographic range of vector-borne diseases have been expanding in recent decades, attributed in part to global climate change. Blacklegged ticks (Ixodes scapularis), the primary vector for multiple tick-borne pathogens in North America, are spreading rapidly beyond their historic post-colonial range and are thought to be constrained mainly by winter temperature at northern latitudes. Our research explored whether winter climate currently limits the distribution of blacklegged ticks and the pathogens they transmit in Maine, U.S.A., by contributing to overwinter mortality of nymphs. We experimentally tested tick overwinter survival across large-scale temperature and snowfall gradients and assessed factors contributing to winter mortality in locations where blacklegged tick populations are currently established and locations where the blacklegged tick has not yet been detected. We also tested the hypothesis that insulation in the tick microhabitat (i.e., by leaf litter and snowpack) can facilitate winter survival of blacklegged tick nymphs despite inhospitable ambient conditions. Overwinter survival was not significantly different in coastal southern compared to coastal and inland northern Maine, most likely due to sufficient snowpack that protected against low ambient temperatures at high latitudes. Snow cover and leaf litter contributed significantly to overwinter survival at sites in both southern and northern Maine. To further assess whether the current distribution of blacklegged ticks in Maine aligns with patterns of overwinter survival, we systematically searched for and collected ticks at seven sites along latitudinal and coastal-inland climate gradients across the state. We found higher densities of blacklegged ticks in coastal southern Maine (90.2 ticks/1000 m²) than inland central Maine (17.8 ticks/1000 m²) and no blacklegged ticks in inland northern Maine. Our results suggest that overwinter survival is not the sole constraint on the blacklegged tick distribution even under extremely cold ambient conditions and additional mechanisms may limit the continued northward expansion of ticks.