犬细粒棘球绦虫感染LAMP检出日期的确定

目的确定犬细粒棘球绦虫感染环介导等温扩增技术(LAMP)最早检出日期。方法家犬8只,口服喂饲细粒棘球绦虫原头节,建立细粒棘球绦虫感染动物模型。感染后40d收集犬粪,用LAMP检测粪便中细粒棘球绦虫目的基因并与传统的PCR比较。结果 8只犬均获得细粒棘球绦虫感染,感染后第18dLAMP法检查犬粪中细粒棘球绦虫目的基因均阳性,较普通PCR法提早2d。结论 LAMP法简便、快捷、灵敏,有望成为早期诊断犬细粒棘球绦虫感染的重要手段。     

家犬粪便中的细粒棘球绦虫DNA PCR检测方法的建立

目的 建立检测家犬粪便中细粒棘球绦虫DNA的PCR方法，为开展流行病学监测提供检测手段。方法 犬粪经液氮反复冻溶后提取DNA，PCR扩增编码细粒棘球绦虫12srDNA检测该靶DNA片段（255bp）。结果 10只细粒棘球绦虫感染犬，8只（体内成虫数〉80条）阳性，2只（体内成虫数分别为4条和5条）阴性。4只未感染家犬粪样及其他3种绦虫DNA样本均为阴性。结论 初步建立了灵敏、特异的检测家犬粪便中细粒棘球绦虫的PCR方法。     

基于线粒体ND6基因检测犬感染细粒棘球绦虫的粪便PCR方法

目的 旨在了解动物包虫病流行区内犬细粒棘球绦虫的感染情况。方法 本研究利用Qiagen DNeasy Powersoil试剂盒对犬粪提取DNA,并从细粒棘球绦虫线粒体全基因组中筛选出完整线粒体ND6基因作为靶基因,建立一种可对犬粪中细粒棘球绦虫同时进行检测及基因分型的PCR方法。结果 该法特异性很高,仅能扩增出细粒棘球绦虫的目的条带而对照组均无条带扩增。其灵敏度达到4 pg的DNA含量。当犬人工感染约50 000只原头蚴时,该法最早可以扩增出感染第13 d粪便中的ND6目的基因。同时,对40份随机采自包虫病流行区的待检犬粪进行PCR检测,共有6份样品可扩增出目的条带且其基因型均属G1型,其检测及分型结果均与经典基因分型依据(COX1基因片段)的结果一致。结论 本研究建立的粪便PCR方法具有很高的特异性和灵敏度,并可用于检测犬的细粒棘球绦虫早期感染情况。对于PCR检测阳性者,其产物经测序分析后也可用于细粒棘球绦虫的基因分型及种群遗传结构的分析研究。     

环介导等温扩增技术(LAMP)检测棘球绦虫感染犬粪DNA的研究

目的 建立快速检测棘球绦虫感染犬粪便的DNA检测方法一环介导等温扩增技术(loop-mediated isothermal amplification.LAMP).方法 针对细粒棘球绦虫线粒体DNA Cox1基因6个位点特异性的设计4条LAMP引物,利用LAMP法和普通PCR方法同时检测棘球绦虫、肥胖带绦虫以及犬肠道内...     

PCR方法诊断家犬感染细粒棘球绦虫的特异性及在临床诊断中的应用价值

目的验证PCR方法检测终宿主家犬感染细粒棘球绦虫的特异性及其在临床诊断中的应用价值。方法取感染细粒棘球绦虫家犬粪便,显微镜下计数细粒棘球绦虫虫卵,稀释后PCR检测其敏感性。同时取家犬小肠内水泡带绦虫、多头绦虫、羊绦虫,将其DNA与细粒棘球绦虫DNA一起进行PCR扩增,观察其特异性。对133 bp的目标条带进行序列测定,对比分析。结果PCR检测终宿主家犬感染细粒棘球绦虫具有高度的灵敏性,即使粪便中有1个虫卵(8pg的DNA),也能测出,但扩增后特异性较差,无法利用扩增带型进行诊断。4种寄生虫均具有相同的133 bp DNA重复序列,在400 bp均可检测出相同条带。结论PCR方法检测终宿主感染细粒棘球绦虫DNA重复序列尽管有优良的灵敏性,因其特异性差,不适合用于临床诊断和推广。     

环介导等温扩增技术(LAMP)检测棘球绦虫感染犬粪DNA的研究Ⅱ

目的 为有效地控制预防流行区犬科动物的棘球绦虫感染情况,建立一种快速检测棘球绦虫感染犬的粪便DNA检测方法—环介导等温扩增技术(loop-mediated isothermal amplification. LAMP)。方法 针对细粒棘球绦虫线粒体DNA ND2基因6个位点特异性的设计4条LAMP引物,利用LAMP法和普通PCR方法同时检测棘球绦虫、肥胖带绦虫以及犬肠道内的其它寄生虫DNA来验证LAMP方法的特异性;将转入ND2基因片段的质粒作为标准阳性对照,并做梯度稀释后同时用 LAMP 和 PCR 方法进行检测比较两者的敏感性。此外,将采集的46份犬粪便标本提取DNA,分别运用LAMP和犬尸体剖检进行感染犬的初步检测评估。结果 E.g mtDNA ND2基因的LAMP引物能够鉴别多房棘球绦虫和细粒棘球绦虫这两个相近的种属,并不与其它待检寄生虫发生交叉反应,且最低检测限度为4×10¹拷贝(灵敏度比普通PCR高出10³倍)。在初步对46份犬粪便DNA检测结果中 ND2 LAMP 引物显示出较好的灵敏度和特异度,χ²检验结果该方法与犬尸体剖检方法的诊断效果无统计学差异。结论 本研究初步建立了LAMP技术检测细粒棘球绦虫感染犬的新方法,在各项特异度、灵敏度和样本检测中展现出较好的效果。该方法不需要昂贵的仪器设备和繁琐的电泳分析过程,有望成为流行区和基层兽医站细粒棘球绦虫感染犬检测的新方法。     

基于重组酶介导等温扩增技术的3种棘球绦虫核酸检测方法的建立及初步应用

目的　基于重组酶介导的等温扩增技术（recombinase⁃aided isothermal amplification assay, RAA）建立一种快速检测多房棘球绦虫、细粒棘球绦虫和石渠棘球绦虫的多重核酸检测方法,并对其检测效果进行初步评价。方法　分别以多房棘球绦虫（GenBank登录号：NC_000928）、细粒棘球绦虫（GenBank登录号：NC_044548）和石渠棘球绦虫（GenBank登录号：NC_009460）线粒体基因组序列为靶序列,依据RAA引物设计基本原则设计、合成3对引物,并进行多重RAA扩增。分别扩增不同浓度3种棘球绦虫基因组DNA和不同浓度含3种靶基因的重组质粒,以评价多重RAA检测方法的敏感性;同时采用该方法检测3种棘球绦虫及多头带绦虫、牛带绦虫、亚洲带绦虫、犬复孔绦虫、泡状带绦虫、犬弓首蛔虫、肝片形吸虫、豆状带绦虫、中线绦虫和犬隐孢子虫基因组DNA,以评价该方法的特异性。优化建立的多重RAA法的条件,再检测棘球蚴病病变组织样本、模拟犬粪便样本和现场狐狸粪便样本,以评价该方法的应用价值。结果　所建立的多重RAA检测方法可在39 ℃时40 min内特异性扩增多房棘球绦虫、细粒棘球绦虫和石渠棘球绦虫线粒体基因片段,长度分别约为540、430 bp和200 bp。该多重RAA法对多房棘球绦虫、细粒棘球绦虫和石渠棘球绦虫基因组DNA的最低检测限为2.0、2.5 pg/μL和3.1 pg/μL,对含多房棘球绦虫、细粒棘球绦虫和石渠棘球绦虫靶基因的重组质粒的最低检测限均可达到200拷贝/μL;该多重RAA法可以同时检测出多房棘球绦虫、细粒棘球绦虫和石渠棘球绦虫单一感染和多重感染,对多头带绦虫、牛带绦虫、亚洲带绦虫、犬复孔绦虫、泡状带绦虫、犬弓首蛔虫、肝片形吸虫、豆状带绦虫、中线绦虫和犬隐孢子虫无扩增。优化后的多重RAA法能够检测出全部棘球蚴病病变组织样本及模拟犬粪样本和现场狐狸粪便样本中的阳性样品,且与单一PCR法检测结果完全一致。结论　成功建立了一种可用于多房棘球绦虫、细粒棘球绦虫和石渠棘球绦虫基因组DNA快速检测的多重RAA法,特异性和敏感性均较高。     

现场应用粪抗原检测法诊断犬细粒棘球绦虫感染的效果评价

目的　评价粪抗原检测法在包虫病流行病学监测中的实际应用价值。　方法　家犬在采集粪便后 ,进行槟榔碱导泻 ,应用粪抗原检测法检测粪样中的细粒棘球绦虫抗原 ,并与槟榔碱导泻法的驱虫结果比较 ,同时分析犬肠道中寄生的其它蠕虫对粪抗原检测结果的影响。　结果　在 2 94只槟榔碱导泻成功的家犬中 ,4 5只检出细粒棘球绦虫 ,粪抗原阳性犬共 4 6只。二者的符合率为 97.8%。在 2 4 9只未检出细粒棘球绦虫的家犬中 ,粪抗原阳性者 1只。　结论　粪抗原检测法诊断犬细粒棘球绦虫感染具有较高的敏感性和特异性。可作为包虫病常规监测方法推广应用。     

现场应用粪抗原检测法诊断犬细粒棘球绦虫感染的效果评价

目的 评价粪抗原检测法在包虫病流行病学监测中的实际应用价值。方法 家犬在采集粪便后，进行槟榔碱导泻，应用粪抗原检测法检测粪样中的细粒棘球绦虫抗原，并与槟榔碱导泻法的驱虫结果比较，同时分析犬肠道中寄生的其它蠕虫对粪抗原检测结果的影响。结果 在294只槟榔碱导泻成功的家犬中，45只检出细粒棘球绦虫，粪抗原阳性犬共46只。二者的符合率为97．8％。在249只未检出细粒棘球绦虫的家犬中，粪抗原阳性者1只。结论 粪抗原检测法诊断犬细粒棘球绦虫感染具有较高的敏感性和特异性。可作为包虫病常规监测方法推广应用。     

基于cox2基因的细粒棘球绦虫环介导等温扩增检测方法的初步建立

目的建立一种安全、快速、高效的细粒棘球绦虫(Echinococcus granulosus)的诊断方法——环介导等温扩增方法(loop-mediated isothermal amplification,LAMP)。方法根据细粒棘球绦虫线粒体细胞色素c氧化酶亚基2(cytochrome c oxidase subunit 2,cox2)基因序列,设计4条LAMP引物,建立LAMP检测方法,采用LAMP法和常规PCR法检测细粒棘球绦虫、泡状带绦虫(Cysticercus tenuicollis)、扩展莫尼茨绦虫(Moniezia expansa)、羊曲子宫绦虫(Thysaniezia ovilla)、中点无卵黄腺绦虫(Avitellina centripunctata)、鞭毛线虫(flagella nematodes)、肝片吸虫(Fasciola hepatica)、多房棘球绦虫(E.multilocularis)和捻转血矛线虫(Haemonchus contortus)等9种寄生虫的DNA以验证LAMP法的特异性;分别用LAMP法和常规PCR法检测梯度稀释的含cox2基因片段的细粒棘球绦虫标准质粒后,比较两者的敏感性。采用LAMP、PCR和夹心ELISA法检测50份犬粪样,计算细粒棘球绦虫cox2基因的阳性率,评价所建立的LAMP法检测效果。结果LAMP法的特异性验证结果表明,仅在以细粒棘球绦虫DNA为模板的反应体系中出现特异性产物。LAMP法在细粒棘球绦虫标准质粒浓度为16.09 ag/μl时仍可见梯状条带,而常规PCR法仅可检测到浓度为16.9 fg/μl以上的质粒,LAMP法灵敏性是常规PCR法的1 000倍。对50份犬粪中细粒棘球绦虫DNA的检测结果显示,PCR、LAMP和夹心ELISA法检测结果相同,阳性率为8.0%(4/50)。结论基于细粒棘球绦虫线粒体cox2基因的LAMP检测方法操作方便、特异性较强、敏感性较高,适于细粒棘球绦虫感染犬的快速检测。     

Copro-diagnosis of Echinococcus granulosus infection in dogs by amplification of a newly identified repeated DNA sequence

Diagnosis of Echinococcus granulosus infection in dogs by detecting adult worms recovered post mortem or purged from the intestines after treatment with arecoline is not suitable for mass screening. Large-scale diagnosis by detection of copro-antigens is useful but only with relatively high intensity infections, and only by genus. To provide a more sensitive and specific diagnosis, a polymerase chain reaction (PCR) assay was developed, that amplified a target repeated sequence (EgG1 Hae III) newly identified in the genome of the common sheep strain of E. granulosus. This repeated sequence consists of approximately 6,900 copies, arranged in tandem, in groups of 2-6 repeats. The corresponding primers used in the PCR easily detected a single egg with no cross-amplification of DNA from closely related cestodes, including E. multilocularis and Taenia spp. Fecal samples from naturally infected dogs, with 2-10,000 E. granulosus worms at necropsy, were all PCR positive, while E. multilocularis or Taenia spp. positive controls as well as non-endemic controls were all PCR negative. This copro-PCR assay was demonstrated to be 100% specific and also detected all necropsy-positive E. granulosus-infected dogs. It is suggested that this copro-PCR assay has the potential for pre-mortem diagnosis of E. granulosus infection even in areas where E. granulosus and E. multilocularis are co-endemic.     

Evaluation of three PCR assays for the identification of the sheep strain (genotype 1) of Echinococcus granulosus in canid feces and parasite tissues

The performance of 3 PCR assays for the identification of the G1 sheep genotype of Echinococcus granulosus was evaluated using tissue and canid fecal samples. The "Dinkel" and "Stefani?" primers were the most sensitive in detecting E. granulosus DNA in feces of necropsied dogs (73.7% and 100%, respectively). The "Abbasi" primers detected 52.6% of E. granulosus infected dogs but were the most species-specific, cross-reacting only with Echinococcus shiquicus (tissue 90.9%; feces 75%). The Stefani? primers were the least specific (tissue, 27.3%; feces, 25%) for E. granulosus. The Dinkel primers also showed inter-species cross-reactivity (tissue, 63.6%; feces, 100%) but were found to be strain-specific for the E. granulosus G1 sheep genotype. Improvement of PCR tests for Echinococcus species and subspecific variants should rely on the use of less-conserved genes and development of protocols that improve the quality and quantity of DNA extracted from feces.     

Specific antibody responses in dogs experimentally infected with Echinococcus granulosus

Six dogs reared helminth-free were divided into 2 groups. Four dogs were infected per os with 200,000 protoscoleces each of Echinococcus granulosus and 2 were kept as uninfected controls. All the dogs were kept together until 32 days after infection, when 1 infected dog was killed, its intestine removed and the contents examined to confirm that the infection with E. granulosus had been successful. The remaining 3 infected dogs were transferred to high security housing and their feces inspected daily to establish the time infections became patent. The infected and control dogs were bled every 5 days for 75 days from the time of infection and the sera were stored at -70 degrees C. Sera were tested by the enzyme-linked immunosorbent assay (ELISA) for antibodies to E. granulosus scolex excretory/secretory (ES) antigen, protoscolex antigen and oncosphere antigen. Antibodies to scolex ES antigen and protoscolex antigen were detected in the sera of infected dogs within 2 weeks of infection. Antibody titers rose rapidly and remained at a high level until the dogs were killed 75 days after infection. Antibodies in these sera did not cross react with antigens prepared from Taenia ovis, T. hydatigena, T. pisiformis, Ancylostoma caninum, Trichuris vulpis and Toxocara canis.     

The epidemiology of Echinococcus granulosus in Great Britain. V. The status of subspecies of Echinococcus granulosus in Great Britain

Twenty-five years ago Williams and Sweatman suggested that in Great Britain there are two subspecies of Echinococcus granulosus--E. granulosus granulosus and E. granulosus equinus. Echinococcus granulosus granulosus does not mature either in foxes or in horses: E. granulosus equinus will mature in either. The prepatent period of E. granulosus granulosus in the definitive host is about 42 days while that of E. granulosus equinus is about 70 days. Each subspecies has a characteristic morphology. More recently, in the course of seven experiments, dogs, red foxes (Vulpes vulpes crucigera), arctic foxes (Alopex lagopus), badgers (Meles meles), domestic ferrets and domestic cats have been infected with protoscoleces derived from hydatid cysts of human, equine and ovine hosts from different regions of England and Wales. Transmissions to horses and sheep were always succeeded by the development of viable hydatid cysts; transmissions to dogs and foxes, by the development of gravid adults. The prepatent period in both dogs and foxes was invariably about 70 days (or longer) and the morphology of all the adult parasites in these definitive hosts was characteristic of E. granulosus equinus. All the evidence derived from these experiments supports the view that there is, in Great Britain, but one subspecies of E. granulosus. That one subspecies is E. granulosus equinus. It infects dogs, red foxes, arctic foxes (experimentally), cats (experimentally), humans, sheep, goats, horses, donkeys, pigs, cattle, roe deer and reindeer (in Scotland). Attempts to transmit E. granulosus to badgers and domestic ferrets were unsuccessful. Of 123 cats infected with protoscoleces of horse origin, one gravid adult parasite was recovered from one animal.     

检测日本血吸虫感染性钉螺PCR方法的建立

目的 建立灵敏、特异的检测日本血吸虫感染性钉螺的PCR方法。 方法 根据日本血吸虫18S小亚基单位核糖体核酸（18S-rRNA）基因设计1对引物，建立检测日本血吸虫感染性钉螺的PCR方法。测定PCR产物的DNA序列，稀释血吸虫毛蚴DNA进行PCR方法的灵敏性试验，扩增单尾尾蚴感染的钉螺DNA进行交叉反应试验，并根据不同稀释度的感染性钉螺DNA的扩增结果来验证PCR的群体检测效果。 结果 PCR扩增日本血吸虫感染性钉螺，得到了与靶DNA片段位置相同的产物，测序片段长度为469 bp，与靶DNA相同且序列一致，并将序列登录GenBank(注册号：DQ442999)。扩增阴性钉螺无产物出现。灵敏性试验提示，PCR可检出日本血吸虫毛蚴DNA的最低浓度为40 pg/μl；交叉反应试验显示，PCR方法不能扩增出单尾尾蚴感染钉螺的DNA；群体检测试验表明，PCR可检出感染性钉螺提取的DNA最高稀释度为1∶640。 结论 初步建立的检测日本血吸虫感染性钉螺的PCR方法灵敏、特异且具有良好的群体检测效果。