Epidemiology of Taenia solium in Nepal: is it influenced by the social characteristics of the population and the presence of Taenia asiatica?

The transmission of the zoonotic pork tapeworms Taenia solium and T. asiatica depends on a combination of specific risk factors, such as open defecation, backyard pig raising and the consumption of raw or undercooked pork and viscera. A community‐based survey was conducted among 289 households in south–eastern Nepal to study the heterogeneity of these risk factor frequencies as a function of the social composition of the population. The frequency of open defecation, backyard pig raising and pork consumption differed significantly (P < 0.005) among the different coexisting caste and ethnic groups. In the same survey, the taeniosis prevalence was examined among the different groups. Tapeworm carriers were identified at a high prevalence among the Dum, one of the most disadvantaged communities of Nepal. A PCR‐RFLP assay revealed that all collected tapeworm specimens were T. asiatica, a species thus far not known to occur in South Asia. These results can help to understand the epidemiology of T. solium in Nepal, which appears to be more complex than thought so far.     

Differentiating Taenia eggs found in human stools: does Ziehl‐Neelsen staining help?

Objective To determine whether Ziehl‐Neelsen staining can differentiate Taenia solium from Taenia saginata eggs. Methods Tapeworm proglottids (33 specimens, 23 T. solium and 10 T. saginata) and eggs (31 specimens, 13 T. solium and 18 T. saginata) were stained. Four eggs from each sample were measured and average diameters were recorded. Results Taenia saginata eggs stained entirely magenta in seven of 13 cases. Taenia solium eggs stained entirely blue/purple in 4/18 cases and entirely magenta in one. Eggs of T. saginata were slightly larger and always ovoid, while T. solium eggs were smaller and mostly spheric. Conclusions Ziehl‐Neelsen staining can occasionally distinguish fully mature T. solium from T. saginata eggs, but this distinction is neither very sensitive nor completely specific. Differential staining suggests differences in embryophore components between species which become evident with egg maturation. In this small series, egg morphology (shape, maximal diameter) provided appropriate differentiation between T. solium and T. saginata eggs.     

分子生物学技术在带绦虫分类中的应用

传统的带绦虫分类是根据成虫和囊尾蚴的形态特征,有一定的局限性,尤其是对形态相近的虫种鉴别困难.近年来发展的分子生物学技术从基因水平检测带绦虫种间或种内个体间的遗传差异,若将两者有机结合,虫种鉴别将更加全面和客观.该文综述了PCR-限制性片段长度多态性技术(polymerase chain reaction-restriction fragment length polymorphism,PCR-RFLP)、随机扩增多态性DNA(randomly amplified polymorphic DNA,RAPD)、DNA序列分析等分子生物学技术在带绦虫分类研究中的应用.     

猪带绦虫和牛带绦虫卵的超微结构鄄观察

本文应用扫描电镜（ＳＥＭ）和透射电镜（ＴＥＭ）对猪带绦虫虫卵和牛带绦虫虫卵的超微结构进行了比较观察，证实了两种绦虫的卵壳结构基本相同，从外向内由五层结构组成：外层为卵黄层（ｖｉｔｅｌｌｉｎｅｌａｙｅｒ，ＶＬ），向内为胚膜层（ｅｍｂｒｙｏｐｈｏｒｅ，Ｅ），胚膜层又由３层组成：致密层（ｄｅｎｓｉｔｙｌａｙｅｒ，ＤＬ）、胚块层（ｅｍｂｒｙｐｈｏｒｉｃｂｌｏｃｋ，ＥＢ）和颗粒层（ｇｒａｎｕｌｅｌａｙｅｒ，ＧＬ），最内为六钩蚴膜（ｏｎｃｈｏｓｐｈｅｒａｌｍｅｍｂｒａｎｅ，ＯＭ）也称幼虫膜。     

猪囊尾蚴病免疫和诊断抗原的分子生物学研究进展

猪囊尾蚴病是一种危害严重的人兽共患寄生虫病。猪囊尾蚴特异性和保护性抗原的研究是猪带绦虫病、猪囊尾蚴病免疫和诊断的基础。天然抗原来源有限,限制了其应用,而重组抗原的应用可解决质量控制和抗原来源的问题。该文就近年来猪囊尾蚴病免疫和诊断抗原的分子生物学研究进展进行了综述。     

猪带绦虫TSOL18疫苗的研制现状

猪囊尾蚴病是一种严重危害人类健康的人兽共患寄生虫病,主要流行于中非、南非、拉丁美洲、东亚和南亚等地区.采用疫苗防治该病是当前研究的热点.该文对TSOL18的编码基因、DNA疫苗和蛋白疫苗等方面的研究现状进行了综述.     

云南、贵州两省38条人体带绦虫的分子鉴别

目的对采自云南、贵州两省的38条人体带绦虫进行分子鉴别,了解当地猪带绦虫、牛带绦虫和亚洲带绦虫的分布状况。方法对云南大理和贵州都匀及从江地区有排节片史的病人以槟榔-南瓜子法驱虫,虫体经形态学初步鉴别后,以组织DNA提取试剂盒提取虫体基因组DNA,分别采用亚洲带绦虫、牛带绦虫和猪带绦虫线粒体细胞色素C氧化酶亚单位1基因(cox1)片段的特异性引物对各DNA样品进行常规PCR扩增和琼脂糖凝胶电泳检测;PCR阴性样品采用带绦虫cox1片段PCR通用引物进行扩增,并选择1份亚洲带绦虫特异性PCR阳性的样品作为对照。从3种带绦虫PCR阳性的扩增产物中各选择1份进行核酸序列测定,并用NCBIBlast将各核酸序列与GenBank数据库中带绦虫的cox1进行比对分析。结果采自大理的4条带绦虫(DL1～4)的猪带绦虫cox1片段PCR为阳性,扩增产物约980bp;其余25条大理带绦虫(DL5～29)和5条都匀带绦虫(DY1～5)的亚洲带绦虫cox1片段PCR为阳性,扩增产物约260bp;各样品的牛带绦虫cox1片段PCR均为阴性。DL2PCR产物的核酸序列与GenBank中猪带绦虫cox1的同源性为99%～100%,DY1PCR产物的核酸序列与亚洲带绦虫cox1的同源性为100%。特异性PCR均阴性的4条从江带绦虫(CJ1～4)和亚洲带绦虫特异性PCR阳性的DL7以带绦虫cox1片段通用引物的PCR扩增出约1kb的产物。测序表明,CJ1片段的核酸序列与牛带绦虫cox1的同源性为99%,DL7与亚洲带绦虫cox1的同源性为99%～100%。结论cox1片段PCR扩增和核酸测序分析表明,采集的云南大理人体带绦虫为猪带绦虫和亚洲带绦虫,贵州都匀和从江人体带绦虫分别为亚洲带绦虫和牛带绦虫。     

带绦虫精母细胞发生的超微结构观察

目的：在超微结构水平研究带绦虫精母细胞的发生。方法：透射电镜。结果：本文对猪带绦虫，牛带绦虫，及豆状带绦虫的精母细胞的发生进行了ＴＥＭ观察，结果精母细胞的发生（ｓｐｅｒｍａｔｏｃｙｔｏｇｅｎｅｓｉｓ）可分辨出两种精原细胞：Ａ型和Ｂ型，以及包绕其周围的支持细胞。Ａ型精原细胞为干细胞。Ｂ型为母细胞。Ｂ型精原细胞经４次无细胞分离的有丝分裂，形成１６个初级精母细胞，其特点为胞质中存在核糖体团。初级精母细胞经减数分裂产生３２个次级精母细胞，排列成玫瑰花团样。次级精母细胞经短暂的发育过程很快形成精细胞。结论：带绦虫精原细胞的分裂方式为无细胞分离的有丝分裂。     

分子分类结合形态学方法对云南大理带绦虫的鉴定

目的 鉴定云南大理洱源(E1-E2)、鹤庆(H1-H2)、双廊(SL)、挖色(WS)带绦虫的种.方法 首先对大理分离株带绦虫成虫进行形态学鉴定,从成虫节片中抽提DNA,PCR扩增线粒体DNA细胞色素B(mtDNA-Cyth)的部分序列并测序;结合GenBank中已知猪带绦虫、牛带绦虫和亚洲带绦虫mtDNA-Cytb序列,经DNAMAN软件处理后构建系统发育树状图.结果大理带绦虫E1的形态和牛带绦虫相似,系统发育树显示大理分离株E1、E2、SL、WS带绦虫标本与亚洲带绦虫的遗传距离最接近,距牛带绦虫较远,与猪带绦虫则更远.大理分离株H1、H2带绦虫标本与猪带绦虫的遗传距离最近,距牛带绦虫和亚洲带绦虫则较远.结论 经形态学和分子生物学鉴定,云南大理分离株E1、E2、SL、WS带绦虫标本属于亚洲带绦虫,而H1、H2株带绦虫标本属于猪带绦虫.     

Neurocysticercosis: is serology useful in the absence of brain imaging?

Neurocysticercosis (NCC) is endemic in most parts of the world and is now recognised as an important contributor to neurological disease. Serological diagnosis of NCC improved greatly in the past two decades and contributed to demonstrating previously unsuspected regions of endemicity. Claims for an accurate serological screening tool for human cysticercosis are frequently raised. However, after symptomatic therapeutics are applied, management of NCC is driven by the characteristics of the central nervous system infection in terms of viability, number, location size and evolutionary stage of parasites, as well as by the resulting inflammation. It is unclear whether, in the absence of neuroimaging, serological confirmation of aetiology of suspected cases (neurologically symptomatic) or detection of asymptomatic cases in population screening would affect their management or prognosis.     

猪带绦虫囊尾蚴的发育过程及形态观察

目的　观察猪带绦虫囊尾蚴的发育过程及其形态变化 ,以确定虫体的出现时间和成熟时间。　方法　仔猪感染猪带绦虫卵后不同时间剖杀 ,取各部位组织检查囊尾蚴的分布。剥离囊尾蚴作压片及组织切片 ,显微镜下观察其形态。　结果　猪囊尾蚴主要分布在肌肉组织 ,其次是脑、肝、肺、肾等器官。同一宿主不同部位甚至同一宿主同一部位囊尾蚴处于不同的发育阶段。感染后 19d仅在骨骼肌中发现幼期囊尾蚴 ,头节区未见吸盘和小钩。组织学检查显示了早期发育的头节。感染后 3 0d的囊尾蚴出现小钩及吸盘的雏形 ,随感染时间的延长 ,吸盘直径及小钩长度增加。感染后 60d ,囊尾蚴头节区出现较大的吸盘和许多折叠。 60d以后的囊尾蚴在形态学上与 60d的相似。在每一发育阶段均有退化变性的囊尾蚴出现。　结论　猪体感染猪带绦虫卵后 ,囊尾蚴 19d出现 ,60d成熟。     

ULTRASTRUCTURAL OBSERVATION ON SPERMATOCYTOGENESIS IN TAENID CESTODES

Ｔｈｅｓｐｅｒｍａｔｏｇｅｎｅｓｉｓｉｎｃｅｓｔｏｄｅｓｗａｓｓｔｕｄｉｅｄｂｙｅａｒｌｉｅｒｗｏｒｋｅｒｓ．ＴｈｅＭｏｎｉｅｚｉａｅｘｐａｎｓａｗａｓｄｅｓｃｒｉｂｅｄｂｙＣｈｉｌｄ（１９０６）ｗｈｏｓｕｇｇｅｓｔｅｄｔｈａｔｔｈｅｆｏｕｒｋｉｎｄ...     

The inflammatory reaction surrounding Taenia solium larvae in pig muscle: ultrastructural and light microscopic observations

Summary An inflammatory reaction with the general characteristics of a chronic granuloma surrounding Taenia solium larvae in pig muscle is described. Larvae with an inflammatory capsule were obtained at slaughter from pigs 6–8 months-of-age and were processed for light and electron microscopy. Eosinophils (granulocytes with orange staining and peroxidase-positive granules) were found to be degranulated and in close contact with the parasite surface. Histiocytes, epithelioid cells, macrophages and lymphocytes were also evident, as well as large numbers of plasma cells in the outer areas of the well-circumscribed reaction. The parasites were ultrastructurally intact, with a normal tegument and only occasional changes in the microvesicles. The results are discussed with reference to parasite survival in the host.     

山东省猪带绦虫病和囊尾蚴病流行病学调查

目的　调查山东省猪带绦虫病和囊尾蚴病流行现状。　方法　采用现场访问、粪便检查及血清学检测等方法对猪带绦虫病和囊尾蚴病人群的感染流行状况、猪囊尾蚴感染情况及有关流行因素进行调查分析。　结果　全省人群猪带绦虫病和囊尾蚴病平均患病率分别为 0 .0 4 8%和 0 .0 5 7% ,抗囊尾蚴特异性 Ig G4 抗体阳性率平均为 1.91%。各地区流行程度不同 ,性别及城乡人群患病率均无显著性差异。流行因素调查结果表明 ,居民普遍存在不卫生习惯 ,如 :切菜刀、板生熟不分 ,饭前便后不洗手等。“连茅圈”养猪占 92 .3% ,粪便管理及生活环境卫生均较差。囊尾蚴病猪检出率平均为 0 .0 6 % ,囊尾蚴抗体阳性率平均为 1.99%。　结论　山东省绦虫病和囊尾蚴病患病率呈下降趋势 ,但流行范围扩大 ,各地区流行程度不同 ,各种流行因素远未得到控制     

猪带绦虫45W蛋白疫苗的研制现状

猪囊尾蚴病是一种严重危害人类健康的人兽共患寄生虫病,主要流行于中非、南非、拉丁美洲、东亚和南亚等地区。采用疫苗防治该病是当前研究的热点。本文对45W蛋白的起源、编码基因和45W蛋白疫苗等方面的研究现状进行了综述。     

Detection of IgG in cerebrospinal fluid for diagnosis of neurocysticercosis: evaluation of saline and SDS extracts from Taenia solium and Taenia crassiceps metacestodes by ELISA and immunoblot assay

We compared saline (S) and sodium dodecyl sulphate (SDS) extracts from Taenia solium (homologous species - HO) and Taenia crassiceps (heterologous species - HE) metacestodes in order to detect IgG by ELISA and immunoblot assay (IBA) in cerebrospinal fluid (CSF) for the diagnosis of human neurocysticercosis (NC). CSF samples were obtained from 93 patients. Of these, 40 had NC, five had a diagnosis of probable NC, nine had central nervous system schistosomiasis or strongyloidiasis and 39 had other neurological alterations. Samples were analysed by ELISA and the results were compared with IBA in all samples with confirmed and probable NC diagnosis, in all samples with other central nervous system parasitic infection, and in 10 of those with another neurological alterations. ELISA sensitivity was 100%, 85%, 95% and 87.5% for the S-HO, S-HE, SDS-HO and SDS-HE extracts, respectively, and ELISA specificity was 100% for S-HO, S-HE, SDS-HO extracts and 97.9% for SDS-HE antigen. Immunodominant peptides detected by IBA were, by decreasing percentage of recognition: 64-68 and 45 kDa for S-HO; 108-114, 92-95, 64-68, 83 and 88 kDa for S-HE; 64-68, 108-114, 77 and 86 kDa for SDS-HO; and 108-114, 88 and 92-95 kDa for SDS-HE. Overall the homologous antigenic extracts showed higher sensitivity than the heterologous extracts in the diagnosis of NC in CSF samples. The heterologous extracts contained most of the immunodominant peptides presented in the homologous extracts, which are recognized by IgG antibodies in CSF samples.     

猪囊尾蚴病DNA疫苗研究现状

猪囊尾蚴病DNA疫苗是近年来出现和发展起来的一种新型疫苗,不仅可以引起体液免疫,而且还能诱导高水平的细胞免疫应答,在猪囊尾蚴病预防方面优势明显。本文就猪囊尾蚴病DNA疫苗的研究现状作一综述。