横川后殖吸虫与扇棘单睾吸虫双重PCR鉴别方法的建立

目的建立一种能快速鉴定横川后殖吸虫(Metagonimus yokogawai)和扇棘单睾吸虫(Haplorchis taichui)的双重PCR方法。方法从Gen Bank中获取横川后殖吸虫和扇棘单睾吸虫以及与其同源性较高的虫种的核糖体DNA第一内转录间隔区(ITS1)序列,应用Primer premier 5.0软件设计2对特异性引物,并优化PCR反应体系和反应条件,建立双重PCR法。将横川后殖吸虫和扇棘单睾吸虫与17个相关虫种一起进行PCR扩增,检测方法的特异性。横川后殖吸虫和扇棘单睾吸虫的ITS1扩增产物经p MD19-T载体进行TA克隆获得质粒,并将质粒进行梯度稀释,检测其敏感性。应用新建的双重PCR法鉴定从47副猫内脏和40副犬内脏中收集的吸虫,检测该方法的准确性和实用性。结果新建的双重PCR法能扩增出横川后殖吸虫和扇棘单睾吸虫的目的片段,大小分别为648 bp和279 bp,不与钩棘单睾吸虫、华支睾吸虫、心形咽口吸虫、次睾属吸虫囊蚴、外睾属吸虫囊蚴、藐小棘隙吸虫、抱茎棘隙吸虫、弗氏棘口吸虫、似锥低颈吸虫、全冠属吸虫、重盘属吸虫、异尖属线虫、东方次睾吸虫、卫氏并殖吸虫、瓦氏瓦生吸虫、背孔属吸虫和宫脂属线虫的DNA发生交叉扩增,具有较好的特异性。敏感性试验表明,应用该双重PCR法,2类吸虫DNA的最低检测值分别为1.49×10-1pg和1.14×10-1pg。对来自猫内脏和犬内脏的吸虫检测表明,该方法能够区分横川后殖吸虫和扇棘单睾吸虫,并且不与猫、狗中其他的吸虫DNA发生交叉扩增。结论本研究所建立的双重PCR法可用于快速鉴定横川后殖吸虫和扇棘单睾吸虫。     

广西发现扇棘单睾吸虫

扇棘单睾吸虫 (Haplorchistaichui)是一种寄生于肠道的异形科单睾属的吸虫 ,成虫主要寄生于鸟类 ,也有感染人体的报道[1,2 ] ,我国未见病例报道。作者在研究华支睾吸虫病时发现一些比华支睾吸虫卵小、肩峰不明显、和异形类吸虫卵相似的虫卵。遂对其感染者进行驱虫治疗 ,检获大量虫体 ,经鉴定为扇棘单睾吸虫 ,在广西为首次发现 。     

基于线粒体细胞色素C氧化酶亚单位1基因鉴别华支睾吸虫和扇棘单睾吸虫的双重PCR法的建立

分别提取华支睾吸虫和扇棘单睾吸虫的基因组DNA,针对两种吸虫线粒体细胞色素C氧化酶亚单位1(COX1)基因设计引物,进行单重和双重PCR扩增。用针对华支睾吸虫的3对引物进行单重PCR扩增,FC1/RC1和FC3/RC3引物分别扩增出328 bp和356 bp的特异性目的条带,而FC2/RC2引物未扩增出任何条带;用针对扇棘单睾吸虫的FH1/RH1和FH2/RH2引物进行单重PCR扩增,分别扩增出200 bp和190 bp的特异性目的条带。用华支睾吸虫FC1/RC1引物,结合扇棘单睾吸虫的FH1/RH1和FH2/RH2引物,分别进行双重PCR扩增,均能扩增出特异性条带,彼此间无干扰。     

华支睾吸虫病患者粪便虫卵核糖体DNA内转录间隔区序列分析

目的 通过PCR方法扩增华支睾吸虫病患者粪便虫卵核糖体DNA （ribosomal DNA,rDNA）内转录间隔区（internal transcribed spacer,ITS）序列进行分析,探讨其用于华支睾吸虫感染检测的价值. 方法 提取2例华支睾吸虫患者粪便中的虫卵DNA作模板,以rDNA ITS基因片段为目的片段进行PCR扩增,对扩增片段进行测序分析. 结果 从2例患者粪便虫卵样本中均扩增出1 123 bp的条带,经序列比对确定患者粪便中的虫卵为华支睾吸虫卵.测序分析发现本研究的两个样本与中国黑龙江分离株（KF740425）相似性为100％. 结论 本研究从2例华支睾吸虫病患者粪便虫卵中成功扩增出rDNA ITS基因,为从分子生物学角度检测华支睾吸虫病提供了资料.     

重组酶介导的华支睾吸虫特异性核酸等温扩增方法的建立及初步评价

目的　建立一种可用于华支睾吸虫检测的重组酶介导的等温核酸扩增方法（RAA）。方法　以华支睾吸虫18S rRNA基因序列作为靶序列,设计、合成、筛选特异性引物和探针,建立快速检测华支睾吸虫的荧光RAA检测方法。分别以含不同拷贝数DNA片段的重组质粒和不同浓度华支睾吸虫基因组DNA为模板进行荧光RAA扩增,评价其检测敏感性;分别以似蚓蛔线虫、细粒棘球绦虫、日本血吸虫、十二指肠钩虫、曼氏血吸虫基因组DNA为模板进行荧光RAA扩增,评价其检测特异性;通过抽提含华支睾吸虫虫卵的粪便及含囊蚴的淡水鱼肉样本DNA并进行荧光RAA扩增,初步评价其检测现场样本的能力。结果　成功建立了华支睾吸虫检测荧光RAA法,其可在39 ℃ 20 min内实现对华支睾吸虫DNA的特异性扩增。以含不同拷贝数DNA片段的重组质粒为模板,该方法最低检出限为10 拷贝/μL;以不同浓度华支睾吸虫基因组DNA为模板,该方法最低检出限为3 pg/μL;以似蚓蛔线虫、细粒棘球绦虫、日本血吸虫、十二指肠钩蚴及曼氏血吸虫基因组DNA为模板,检测结果均为阴性。该方法可成功检出感染华支睾吸虫的人体、大鼠粪便样本以及麦穗鱼样本,具备较好的现场样本检测能力。结论　成功建立了一种简便、快速、敏感、特异的可用于华支睾吸虫检测的RAA法。     

重组酶介导的华支睾吸虫特异性核酸等温扩增方法的建立及初步评价

目的　建立一种可用于华支睾吸虫检测的重组酶介导的等温核酸扩增方法（RAA）。方法　以华支睾吸虫18S rRNA基因序列作为靶序列，设计、合成、筛选特异性引物和探针，建立快速检测华支睾吸虫的荧光RAA检测方法。分别以含不同拷贝数DNA片段的重组质粒和不同浓度华支睾吸虫基因组DNA为模板进行荧光RAA扩增，评价其检测敏感性；分别以似蚓蛔线虫、细粒棘球绦虫、日本血吸虫、十二指肠钩虫、曼氏血吸虫基因组DNA为模板进行荧光RAA扩增，评价其检测特异性；通过抽提含华支睾吸虫虫卵的粪便及含囊蚴的淡水鱼肉样本DNA并进行荧光RAA扩增，初步评价其检测现场样本的能力。结果　成功建立了华支睾吸虫检测荧光RAA法，其可在39 ℃ 20 min内实现对华支睾吸虫DNA的特异性扩增。以含不同拷贝数DNA片段的重组质粒为模板，该方法最低检出限为10 拷贝/μL；以不同浓度华支睾吸虫基因组DNA为模板，该方法最低检出限为3 pg/μL；以似蚓蛔线虫、细粒棘球绦虫、日本血吸虫、十二指肠钩蚴及曼氏血吸虫基因组DNA为模板，检测结果均为阴性。该方法可成功检出感染华支睾吸虫的人体、大鼠粪便样本以及麦穗鱼样本，具备较好的现场样本检测能力。结论　成功建立了一种简便、快速、敏感、特异的可用于华支睾吸虫检测的RAA法。     

不同地域株华支睾吸虫基因差异的研究

目的探讨湖北、广东、辽宁和韩国4地华支睾吸虫的基因差异,为华支睾吸虫种下分型提供依据。方法取湖北、广东两地的华支睾吸虫,提取基因组DNA,PCR特异性扩增18S rDNA V4区并测序;登陆GenBank,检索中国辽宁(AF217100)和韩国(AF408144)的华支睾吸虫18S rDNA的登录序列,应用系统发生学分析法对所有序列进行排列比较,分析4地华支睾吸虫的基因差异,并构建系统发生树,分析其亲缘关系。结果获得的湖北和广东两地华支睾吸虫18S rDNA V4区的碱基数分别为392 bp和440 bp。通过对18S rDNA V4区基因序列的比较与进化树的构建,证实4个地域株华支睾吸虫的18S rDNA V4区具有较高的同源性(98%~100%),彼此间遗传距离较小(0~0.013);在系统发生树中,湖北株和广东株华支睾吸虫形成一个支系,韩国株和辽宁株华支睾吸虫形成另外一个支系。结论以18S rDNA V4区为分子标记的DNA序列分析表明,湖北、广东、辽宁和韩国4地华支睾吸虫存在基因差异,但亲缘关系较近,即起源于共同的祖先。     

华支睾吸虫HMGB1同源分子的识别及其进化研究北大核心CSCD

目的识别华支睾吸虫HMGB1同源分子的CDS及其蛋白序列,并分析其进化特征。方法分别用基于麝猫后睾吸虫HMGB1预测序列的5'和3'RACE以及基于华支睾吸虫HMGB1基因组预测序列的PCR法扩增华支睾吸虫成虫来源的cDNA,对扩增产物进行克隆测序,并进行序列的同源性比较和拼接,分析其ORFs,据此对华支睾吸虫成虫来源的cDNA进行PCR扩增验证其转录;构建进化树,对识别出的HMGB1同源分子进行进化分析。结果识别出两个华支睾吸虫HMGB1同源蛋白CDS,大小分别为381和477 bp,二者均在华支睾吸虫成虫转录,产物均一;推测其编码蛋白分别为127和159个氨基酸,其分子序列与血吸虫同源性较高,而与人及其他脊椎动物同源性低。结论成功识别出华支睾吸虫HMGB1同源蛋白CDS序列,为研究其与肝胆管癌发生的关联性和机制奠定了基础。     

华支睾吸虫cDNA文库的构建

目的　构建华支睾吸虫cDNA文库。方法　采集华支睾吸虫阳性鱼 ,分离囊蚴 ,感染实验动物兔 ,解剖兔收集华支睾吸虫成虫虫体。应用“一步法”提取华支睾吸虫总RNA ;经过mRNA纯化、cDNA合成 ,以PcDNA3(Amp +)质粒为载体构建文库。挑取 2 0个克隆进行扩增 ,选择 9个克隆进行DNA序列测定。序列结果与GenBank中相关基因进行比对。结果　获得含有 9 7× 10 5个重组子库容量的华支睾吸虫cDNA文库。其中PC6号克隆基因序列与华支睾吸虫半胱氨酸蛋白酶序列具有 93%的同源性。结论　已构建成华支睾吸虫cDNA文库。     

重组酶介导的等温核酸扩增技术检测淡水鱼华支睾吸虫囊蚴的初步应用

目的 评价重组酶介导的核酸等温扩增技术(recombinase-aided amplification,RAA)用于淡水鱼肉样本中华支睾吸虫囊蚴检测效果，为后续该方法标准化及现场应用提供科学依据。方法 2022年6—9月在江苏省泰州市姜堰区、兴化市、泰兴市华支睾吸虫感染阳性人群所在行政村河道内采集野生淡水鱼样本。取6份不含华支睾吸虫囊蚴的鱼肉组织(每份5 g)，分别加入0、1、2、4、8、16个华支睾吸虫嚢蚴，提取鱼肉组织基因组DNA后采用荧光RAA法进行检测，评价该方法检测灵敏度；分别以华支睾吸虫、东方次睾吸虫、钩棘单睾吸虫、台湾棘带吸虫嚢蚴基因组DNA为模板，采用荧光RAA法检测，评价其交叉反应；分别采用荧光RAA法和压片法检测现场采集的淡水鱼样本，比较两种方法检测华支睾吸虫效果。结果 含1、2、4、8、16个华支睾吸虫囊蚴的鱼肉组织样本均出现阳性扩增，荧光RAA法可在20 min内对5 g鱼肉组织中含1个华支睾吸虫囊蚴的样本实现阳性扩增；以东方次睾吸虫、钩棘单睾吸虫、台湾棘带吸虫嚢蚴基因组DNA为模板进行RAA检测，结果均为阴性。对采集的1 735条淡水鱼分别采用荧光RAA法和压...     

Discrimination of Opisthorchis viverrini from Haplorchis taichui using COI sequence marker

This study aimed to discriminate infections of two common fish-borne trematodes in Thailand, Opisthorchis viverrini from Haplorchis taichui, based on mitochondrial cytochrome c oxidase subunit I (COI) gene. Designed primers (COI-OV-Hap F&R primers) amplified partial COI fragments of O. viverrini and H. taichui with high sensitivity in different developmental stages (adult, metacercaria, and egg). Polymerase chain reaction (PCR) amplicons were generated with low genomic DNA concentration ( approximately 10(-4)ng) of O. viverrini and H. taichui at 50 and 56 degrees C annealing temperatures, respectively. At 50 degrees C, COI fragments of Clonorchis sinensis and H. taichui were also obtained, but this was less sensitive than O. viverrini. At 56 degrees C, only H. taichui could be amplified and discriminated from H. pumilio, H. yogokawai, O. viverrini, and C. sinensis. Between 50 and 56 degrees C, the PCR amplicons of H. pumilio and H. yogokawai were amplified with low specificity and low sensitivity. The genetic characters among O. viverrini, C. sinensis, and H. taichui were distinguished by PCR-RFLP method. The PCR-RFLP profiles might be useful for diagnosing mixed O. viverrini and H. taichui infections in endemic areas, and for detecting metacercariae of O. viverrini, C. sinensis and H. taichui in epidemiological surveys of infections in fish hosts.     

Nucleotide sequence of mitochondrial CO I and ribosomal ITS II genes of Opisthorchis viverrini in northeast Thailand

The mitochondrial cytochrome c oxidase subunit I (CO I) gene and the second internal transcribed spacer region (ITS II) gene of Opisthorchis viverrini were compared among O. viverrini from various areas in northeast Thailand. The nucleotide sequences of partial CO I gene (417 bp) of O. viverrini differed among O. viverrini originated from Ubon Ratana, Leongpleuy, Ban Phai, Maha Sarakham, and Chatturat. These intraspecific variations were classified into 5 patterns but no area-specific pattem was observed. Amino acid sequence deduced from the nucleotide sequences of these genes was identical. Nucleotide sequences of a region of the O. viverrini ITS II gene (296 bp) from different areas were identical. However, they were different from those of Clonorchis sinensis, Haplorchis taichui, H. pumilio, Fasciola gigantica, Echinostoma malayanum and Centrocestus sp..     

Potassium permanganate staining for differentiation the surface morphology of Opisthorchis viverrini, Haplorchis taichui and Phaneropsolus bonnei eggs

Potassium permanganate staining method was developed for differentiation Opisthorchis viverrini, Haplorchis taichui and Phaneropsolus bonnei eggs. The surfaces of O. viverrini, H. taichui and P. bonnei eggs stained permanently and temporarily were similar in appearance even the staining procedures were varied both in concentration and time. Determined under light microscope set at 400x, all of these eggs were oval-shaped, operculated at one pole and indistinct small knob at posterior end. O. viverrini eggs showed the distinct musk-melon-like prominent ridges on the surface. Haplorchis taichui eggs had a light striae pattern while P. bonnei eggs had a smooth egg shell. Length of these trematode eggs were significant different (chi2 test, p < 0.05). Mean +/- SD of O. viverrini, H. taichui and P. bonnei eggs were 26.34 +/- 1.65 microm, 29.03 +/- 1.48 microm and 23.00 +/- 1.49 microm, respectively. Regarding of their width, the mean +/- SD of O. viverrini, H. taichui and P. bonnei eggs were 15.54 +/- 0.69 microm. 14.94 +/- 0.91 microm and 12.25 +/- 1.02 microm, respectively. The means of width of O. viverrini and H. taichui eggs were not significantly different (chi2 test, p > 0.05), however, they were significantly different from those of P. bonnei (chi2 test, p < 0.05). Temporary staining using 1% w/v concentration and only 1 minute of time is useful in the mass fecal examination survey for the prevalence and intensity of truly Opisthorchis infection.     

Eggshell morphology of the small eggs of human trematodes in Thailand.

Light and scanning electron micrographs of Opisthorchis viverrini, Haplorchis taichui, H. pumilio, A Phaneropsolus bonnei, and Prosthodendrium molenkampi eggs were studied. Under light microscopy. O. viverrini eggs had rough eggshells and prominent shoulders. H. taichui, H. pumilio were similar in shape and had smooth eggshells and prominent shoulders. H. pumilio eggs were bigger than H. taichui eggs. P. bonnei and P. molenkampi eggs had smooth eggshells and indistinct shoulders. P. bonnei eggs were thinner and bigger than P. molenkampi eggs. Some deformed eggs of O. viverrini and Haplorchis sp. were found and they had no embryos and indistinct opercula. Under scanning electron microscopy, O. viverrini eggs looked like musk-melon skin; they had prominent shoulders and long knobs. H. taichui eggs had curly, thread-like ridges and prominent shoulders and knobs. H. pumilio eggs had streched ridges, like Chinese bitter mormodica, and prominent shoulders. P. bonnei and P. molenkampi eggs had smooth eggshells and small shoulders and knobs.     

Discrimination of O. viverrini, C. sinensis, H. pumilio and H. taichui using nuclear DNA-based PCR targeting ribosomal DNA ITS regions

Small liver and minute intestinal flukes are highly prevalent in Southeast Asia, and in mixed infections, their eggs are difficult to differentiate morphologically in fecal samples. PCR assays targeting the ITS regions in ribosomal DNA were designed to identify and differentiate species. The PCR amplicons of Opisthorchis viverrini, Clonorchis sinensis, Haplorchis pumilio, and Haplorchis taichui were 800, 820, 1250, and 930 bp for the ITS1 region, and 380, 390, 380, and 530 bp for ITS2, respectively. The ITS1-region amplicon sizes successfully differentiated 4 species, while only H. taichui were significantly different from the other 3 species in the ITS2 region. PCR assays were employed for preliminary analysis using fecal samples diagnosed as having “small trematode eggs” by modified thick smear, showing 76.2% sensitivity for ITS1 and 95.2% for ITS2.     

广西淡水鱼携带异形科吸虫囊蚴的调查研究

目的了解广西淡水鱼异形科吸虫感染情况。方法使用消化法对从桂北的阳朔县及桂南的南宁市、马山县、扶绥县和宾阳县等地采集的淡水鱼进行检查。结果共检查各种鱼类316尾,分属鲤科33种、Centropomidae科和丽鱼科各1种。鲤科鱼33种中有28种、Centropomidae科的Coreoperca whiteheadi 1种带有异形吸虫囊蚴。共检出后殖吸虫、扇棘单睾吸虫、钩棘单睾吸虫和台湾棘带吸虫等4种异形吸虫囊蚴,其感染率分别为28.2%、27.5%、44.3%和10.8%。桂北检查112尾,后殖吸虫感染率为78.6%;桂南检查204尾,钩棘单睾吸虫感染率最高,为63.2%,其次为扇棘单睾吸虫42.7%和台湾棘带吸虫16.7%,后殖吸虫为0.5%。结论广西各地淡水鱼异形吸虫感染非常普遍和严重,尤以桂南为甚。异形吸虫与华支睾吸虫感染方式相同、流行区域重叠及虫卵形态相似,临床上要注意其鉴别诊断。     

Development of Haplorchis taichui (Trematoda: Heterophyidae) in Mus musculus mice

The development of Haplorchis taichui was studied in sixteen mice, Mus musculus. Metacercarial cysts of H. taichui were obtained from the freshwater fish, Thynnichthys thynnoides, collected in Chiang Mai Province, north Thailand. Approximately 200 active metacercariae were orally introduced into each mouse. Two mice were randomly sacrificed and necropsied daily from day 2-9 postinfection (pi). Two peaks of increment in the length and width of worms were found at day 3 and 7 pi. H. taichui was rapid in maturation, similar to other minute intestinal flukes. Rudimentary sex organs were found at day 2 pi. Spermatozoa in a seminal receptacle, vitellaria and eggs were seen as early as 3 days pi. The number of eggs increased daily to approximately 50-60 eggs thereafter. Mice can serve as a suitable experimental definitive host for harvesting adult H. taichui, especially in 1-week pi.     

Dna quantities and qualities from various stages of some trematodes using optical and HAT-RAPD methods

The aim of this experiment was to minimize DNA quantity and quality for detection by optical (spectrophotometer at 260 nm and 280 nm) and HAT-RAPD methods. Total DNA from different stages, adult, metacercaria and eggs of 6 trematode species were isolated for analysis. In this experiment, the adult trematodes were classified into 3 groups by size: small, Haplorchis taichui and Stellantchasmus falcatus; medium, Opisthorchis viverrini and Ganeo tigrinus; and large, Paramphistomum epiclitum and Fischoederius elongatus. The adult minimal DNA quantities and qualities of all specimen samples detected by optical method were 97.22,72.28, 3,167.00, 1,490.62, 21,382.66, and 27,321.77 ng; eggs were 3.92, 3.57, 3.72, 6.23, 17.53, and 14.01 ng, respectively; and metacercarial stages 50.70 and 40.98 ng in H. taichui and S. falcatus. In addition, the HAT-RAPD technique was chosen to amplify the minimal DNA qualities and quantities of all trematode specimens. Total DNA was 1-1 x 10(-12) ng; DNA templates in each dilution were used for amplification by primer OPA-09. DNA concentrations ranging between 1 x 10(-8) and 1 x 10(-11) ng were amplified with high polymorphism. Our experiment concluded that only a single specimen of each egg, metacercaria, or adult stage could be amplified with distinct bands.     

Prevalence of Opisthorchis viverrini infection among villagers harboring Opisthorchis-like eggs

The precise occurrence of Opisthochis viverrini infection in humans, who were positive for Opisthorchis-like eggs in a stool examination, was determined using the potassium permanganate staining method. In the 68 specimens examined, there were more individual O. viverrini eggs (38.24%) than singular Haplorchis taichui eggs (29.41%). One-fourth of the total specimens contained a mixed infection of O. viverrini and H. taichi eggs. The median ratio of O. viverrini: H. taichui eggs in mixed infection cases was 2.29 (min = 1, max = 17.5). It is suggested that chemotherapy with praziquentel treatment should be given to patients who are positive for O. viverrini-like eggs.