Observations on pathological and histochemical changes in piglet livers infected with Taenia saginata asiatica

To study the pathological and histochemical characteristics of lesions in piglet livers infected with Taenia saginata asiatica (T. saginata asiatica) throughout the different stages, piglets were fed with eggs of T. saginata asiatica and raised in isolation in an animal center to establish the T. saginata asiatica infection model with normal piglets as control. The pathological changes in the piglet livers were observed after the infection using liver sections stained with hematoxylin and eosin. Histochemical methods were used to check the changes in lipid, glycogen and protein content in the liver. The data collected by image analysis were analyzed statistically with Statistical Package for the Social Science. The results show that T. saginata asiatica-exposed piglets were indeed infected. Inflammatory reactions began on the fourth day and progressed rapidly. Kupffer cell hyperplasia, hepatic hydropic degeneration and ballooning degeneration were found in the 10th–20th days after infection. Hepatic central veins and hepatic sinusoids were dilated and congested. Spotty necrosis occurred in some local liver tissues. In the 40th–60th days, granulomatous reactions and mild hepatocirrhosis were the main lesions. In the 70th–80th days, hepatocirrhosis and bile duct proliferation were observed in the liver. In the different stages, lipid drops were increased while glycogen and protein levels were decreased to some degree. There was a significant difference in metabolism between the infected group and the control group (P < 0.01). It is concluded that pigs are the favorable intermediate host of T. saginata asiatica and its infection can result in serious pathological and histochemical lesions in host organs. Translated from Journal of Guiyang Medical College, 2006, 31(4): 296–300 [译自: 贵阳医学院学报]     

Neurocysticercosis in Persons with Epilepsy in Medellín,Colombia

Summary: Purpose: A prospective series of 643 persons with epilepsy attending a reference neurologic center in Medellin, Colombia, was examined by computed tomography (CT scan) or serology or both with the enzyme-linked immunoelectrotransfer blot assay (EITB) to assess the prevalence of Taenia solium cysticercosis. Methods: All presenting patients were consecutively enrolled in the study. Five hundred forty-six persons underwent cerebral CT scans; 376 of them also had serum EITB performed. Results: Prevalence of neurocys@ercosis by CT scan was 13.92%. Overall prevalence of T. solium antibodies with EITB was 9.82%, but for those with late-onset epilepsy (onset after age 30 years), prevalence increased to 17.5% and 19% for those who originated from outside urban Medellin. Seroprevalence in individuals with mixed lesions (cysts and calcifications) was 88.2% and 64.10% in those with live cysts. Conversely, only 2.72% of persons with CT findings not related to neurocysticercosis had positive EITB tests. Conclusions: Our study shows that an important proportion of individuals with epilepsy have radiologic or serologic evidence of T. solium infection, suggesting that neurocysticercosis is an important etiology for epilepsy in Colombia.     

Effect of mebendazole againstEchinococcus granulosus andTaenia hydatigena cysts in naturally infected sheep and relevance to larval tapeworm infections in man

The ability of three treatment schedules of mebendazole to kill well-established hydatid cysts was studied. Pregnant sheep, naturally infected withEchinococcus granulosus and/orTaenia hydatigena, were treated daily with mebendazole at a dose rate of 50 mg/kg body weight for either five days, one month, or three months.At autopsy, seven months after the commencement of treatment, no evidence was found that the 5-day treatment schedule had any damaging effect onE. granulosus cysts. The effects of the one month treatment were equivocal. There was evidence of a damaging effect from the 3-month treatment schedule and protoscoleces were not infective to dogs. NoT. hydatigena cysts survived the 1- and 3-month treatments, but organisms from the 5-day treatment were infective to dogs.These results forE. granulosus in sheep suggest that long-term treatment with mebendazole may be required in hydatid disease in man. The results obtained forT. hydatigena in sheep are discussed in relation to the treatment of cysticercosis fromT. solium in man. Mebendazole showed no untoward effect on the sheep or their lambs.     

Evagination of Taenia solium cysticerci: a histologic and electron microscopy study

BACKGROUND: After a human being ingests a cysticercus, the larval stage of Taenia solium, the cysticercus gradually develops toward the adult parasite. In this paper, we describe the sequential progress of evagination of cysticerci. METHODS: Intact cysticerci were obtained from swine muscle, and incubated in bovine bile to stimulate evagination. Dissecting, light, and electron microscopy of whole parasites and histologic sections were used for photographic registers. RESULTS: The first event was the widening of the opening of the bladder wall for the scolex and neck to emerge. The two chambers that conform the cysticercus were identified. Histologic sections provided explanation for the conformation of the spiral canal.The scolex uncoils during evagination but does not turn inside out. CONCLUSIONS: The scolex and the neck comprise a different structure from the bladder wall, although they are contiguous.     

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.     

云贵两省三地带绦虫的分子鉴定--核糖体DNA第一内转录间隔区(ITS1)限制性酶切片段长度多态性(RFLP)分析

目的用PCR-RFLP方法对rDNA-ITS1片段进行分析,以进一步明确云贵地区是否存在牛带绦虫亚洲亚种,并建立一种快速鉴定方法. 方法 取贵州都匀株(DY)、贵州从江株(CJ)、云南大理株(DL)带绦虫及台湾株(TW)成虫标本,剪取孕节,抽提DNA,PCR扩增rDNA- ITS1片段,分别用4种限制性内切酶MspI、CfoI、AluI、RsaI对扩增片段作酶切分析. 结果 PCR产物经AluI、RsaI酶切后, TW、DL、DY和CJ株RFLP图谱一致;经MspI、CfoI酶切后,TW、DL和DY株RFLP图谱一致,CJ株显著不同. 结论 1)DL和DY株与TW株同属牛带绦虫亚洲亚种;而CJ株是传统牛带绦虫;2)rDNA-ITS1的PCR-RFLP分析方法简便,可以用于带绦虫的分类学研究.     

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。     

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。     

Changing trends in ocular cysticercosis over two decades: an analysis of 118 surgically excised cysts

PURPOSE: To evaluate the frequency of ocular cysticercosis and to demonstrate the changing trends in localisation of ocular cysticercosis along with a brief review of literature. METHODS: A retrospective analysis of histology proven ocular cysticercosis cases seen over a period of 20 years (1981 through 2000) was done. The pathology record forms were reviewed for demographics, clinical features with specific reference to the location of cysts in four subgroups: subconjunctival; intraocular orbit and eyelid. The distribution of cases in four five-year periods namely group A: 1981-1985, group B: 1986-1990, group C: 1991-1995 and group D: 1996-2000 and the changing trends in the location of cysts was evaluated. RESULTS: One hundred eighteen cysts from 118 patients aged 4-72 (mean 17.1) years were submitted to the pathology service of S D Eye Hospital, Hyderabad. Male to female ratio was 1: 1.2. Total number of cases in groups A, B, C and D were 33, 41, 16 and 25 respectively. Location of cysts was subconjunctival - 74 (62.7%); intraocular-31 (26.3%); orbital-8 (7%) and lid-5 (4%). In last 20 years, significant decrease (P =0.0001) was noted in subconjunctival cases (85% vs. 28%) with a significant rise (P =0.0001) in intraocular cysticercosis (6% vs. 60%). CONCLUSIONS: Frequency of surgically excised ocular cysticercosis remained constant over last two decades with an increasing manifestation of intravitreal cysticercosis in the recent years. This could imply either improved diagnostic modalities, available expertise in vitreo-retinal surgery or ineffective medical treatment for intraocular parasitic infection. The relative decrease in extraocular cysticercosis is probably due to the increased preference and success with medical management.     

Perceptions and acceptability of piloted Taenia solium control and elimination interventions in two endemic communities in eastern Zambia

Infections with Taenia solium cause significant public health and economic losses worldwide. Despite effective control tools, long‐term sustained control/elimination of the parasite has not been demonstrated to date. Success of intervention programs is dependent on their acceptability to local communities. Focus group discussions (FGDs) and questionnaires (QS) were conducted in two study communities in eastern Zambia to assess local perceptions and acceptance of two piloted intervention strategies: one targeting pigs only (‘control’ study arm), and one integrated human‐ and pig‐based (‘elimination’) strategy. QS (n = 227) captured data regarding participation in project activities, knowledge and perceptions of T. solium and of the interventional drugs used in the study. FGDs (n = 18) discussed perceived advantages and disadvantages of the interventions and of the project's delivery and value. QS data revealed 67% of respondents participated in at least one educational activity, and 80% correctly identified at least one disease targeted by the education. All elimination study arm respondents (n = 113) had taken the human treatment, and 98% intended to do so next time. Most (70%) indicated willingness to pay for future treatments (median 0.20 USD per dose). Of pig‐owning respondents, 11/12 (92%) had allowed their pigs to be treated/vaccinated and all intended to do so again next time. Four pig owners indicated willingness to pay 0.10–0.50 USD per dose of treatment or vaccine. FGD feedback revealed positive perceptions of interventions; people reported improved health in themselves and their pigs, and fewer cysticerci in pork. Latrine use, hand washing, meat inspection and proper cooking of pork had reportedly increased since the program's inception. Preliminary assessment indicates that the piloted intervention methods are generally acceptable to the communities. The reported willingness of many respondents to pay for the medications would contribute to the feasibility of long‐term, government‐led T. solium intervention programs in future.