Evagination of metacestodes of the WFU strain of Taenia crassiceps and evaluation of the impact of immune suppression of hamsters during tapeworm development.

Taeniosis-cysticercosis caused by Taenia crassiceps (Zeder, 1800) is a useful experimental model for biomedical research, in substitution of Taenia solium Linnaeus, 1758, studied during decades to develop effective vaccination, novel anti-helminthic drugs and diagnostic tools. Cysticercosis in mouse (Mus musculus Linnaeus) is achieved by the larval subculturing of the Wake Forest University (WFU) strain of T. crassiceps. Golden hamster, Mesocricetus auratus (Waterhouse), has been shown to be the most suitable host for adult forms of parasite in experimental taeniosis. Metacestodes of T. crassiceps WFU multiply by budding without restrictions once inoculated into the mouse, while the number of tapeworms developed from these larvae in hamsters remains highly variable. Three objectives have been proposed to improve the infection of T. crassiceps WFU in hamsters: (1) to re-evaluate the need of immune suppression; (2) to investigate the advantage of infecting hamsters with metacestodes with in vitro protruded scolices; and (3) to compare a number of tapeworms developed from metacestodes subcultured in hamsters against those proliferated in mice. Our results demonstrated that when the evagination of murine metacestodes was high, the number of T. crassiceps WFU adults obtained from hamsters was also high. Immunosuppressive treatment remains relevant for this experimental rodent model. The hamster-to-hamster cysticercosis-taeniosis by T. crassiceps overcame the mouse-to-hamster model in the yield of adult specimens. In vitro scolex evagination and metacestode asexual proliferation in hamsters place this rodent model by T. crassiceps WFU as the most affordable experimental models with taeniids.

Molecular and Morphological Characterization of Cysticercus tenuicollis in Red Deer (Cervus elaphus) from Turkey.

INTRODUCTION: Cysticercus tenuicollis, the metacestode stage of Taenia hydatigena has a worldwide distribution and is particularly common in rural areas and developing countries. In rare cases, T. hydatigena infection may result in the death of its host due to severe damage or secondary bacterial infections. Generally, when multiple cysts are attached to the liver, it causes economic losses. The infection can be detected using morphological, histopathological and more recently, molecular investigations. METHODS: In the present study, we describe molecular and morphological characterization of C. tenuicollis detected in a 3 month-old female red deer (Cervus elaphus) during necropsy. Cystic samples were stained with haematoxylin-eosin (HE) and Masson's trichrome stain for histopathological examination, and molecular characterization of the complete mitochondrial cytochrome c oxidase subunit 1 (cox1) gene region was performed. PURPOSE: This study provides the first morphological, histopathological, and molecular data on C. tenuicollis isolated from red deer in Turkey.

Molecular and biochemical characterization of Taenia solium α-enolase.

Enolase (EC 4.2.1.11) acts as a multifunctional enzyme in many organisms, being involved in metabolism, transcription regulation and pathogenesis. In the current study, the recombinant α-enolase from Taenia solium (His-Tseno) was prepared and antiserum against His-Tseno was generated in rabbits. Consequently, we analyzed the enzymatic characteristics, plasminogen binding activity, tissue localization and expression patterns of Tseno. The study demonstrated that the enzymatic activity of His-Tseno was enhanced at pH around 7.0-7.5 and affected by addition of metal ions. Kinetic measurements using 2-phospho-d-glycerate (2-PGA) substrates gave a specific activity of 60.72 ±â€¯0.84 U/mg and 1.1 mM of Km2-PGA value. Plasminogen binding assay showed that His-Tseno could bind to human plasminogen and generate plasmin activated by a tissue-type plasminogen activator (t-PA). In addition, the lysine analogue 6-aminocaproic acid (ε-ACA) could inhibit the binding of plasminogen to His-Tseno. Quantitative real-time PCR confirmed that Tseno was expressed 2.38 folds higher in the adult worms (p < 0.05) than in the cysticerci. Further, an immunolocalization assay indicated that native Tseno was mainly distributed in the tegument and eggs of gravid proglottis from adult T. solium. In conclusion, Tseno executes the innate glycolytic function to supply energy for the growth, egg production, and even invasion of T. solium.

Albendazole and Corticosteroids for the Treatment of Solitary Cysticercus Granuloma: A Network Meta-analysis.

BACKGROUND: Solitary cysticercus granuloma (SCG) is the commonest form of neurocysticercosis in the Indian subcontinent and in travelers. Several different treatment options exist for SCG. We conducted a Bayesian network meta-analysis of randomized clinical trials (RCTs) to identify the best treatment option to prevent seizure recurrence and promote lesion resolution for patients with SCG. METHODS AND PRINCIPAL FINDINGS: PubMed, EMBASE and the Cochrane Library databases (up to June 1, 2015) were searched for RCTs that compared any anthelmintics or corticosteroids, alone or in combination, with placebo or head to head and reported on seizure recurrence and lesion resolution in patients with SCG. A total of 14 RCTs (1277 patients) were included in the quantitative analysis focusing on four different treatment options. A Bayesian network model computing odds ratios (OR) with 95% credible intervals (CrI) and probability of being best (Pbest) was used to compare all interventions simultaneously. Albendazole and corticosteroids combination therapy was the only regimen that significantly decreased the risk of seizure recurrence compared with conservative treatment (OR 0.32, 95% CrI 0.10-0.93, Pbest 73.3%). Albendazole and corticosteroids alone or in combination were all efficacious in hastening granuloma resolution, but the combined therapy remained the best option based on probability analysis (OR 3.05, 95% CrI 1.24-7.95, Pbest 53.9%). The superiority of the combination therapy changed little in RCTs with different follow-up durations and in sensitivity analyses. The limitations of this study include high risk of bias and short follow-up duration in most studies. CONCLUSIONS: Dual therapy of albendazole and corticosteroids was the most efficacious regimen that could prevent seizure recurrence and promote lesion resolution in a follow-up period of around one year. It should be recommended for the management of SCG until more high-quality evidence is available.

Acute visceral cysticercosis by Taenia hydatigena in lambs and treatment with praziquantel.

An acute outbreak of Taenia hydatigena cysticercosis, causing mortality in 5 of 21 (23.8%) female lambs, is reported. Gross post-mortem examinations and histology showed Cysticercus tenuicollis as the cause of death. Biochemical parameters in infected lambs confirmed severe hepatitis. Praziquantel, given once at 15 mg/kg body weight (bw), was administered and a dramatic improvement in the clinical condition and biochemical parameters was observed up to 30 days following treatment.

Effect of heat treatment on viability of Taenia hydatigena eggs.

Effects of heat treatments on activation and infectivity of Taenia hydatigena eggs were assessed. Eggs containing oncospheres were used for in vitro and in vivo studies to determine the response to 5min of heat treatment, ranging from room temperature (22°C) to 60°C. The study demonstrated 99.47% and 100% reduction in oncosphere activation or infectivity after 5min of heat treatment at 60°C and 57.38°C under in vitro and in vivo conditions, respectively. Similar results between the two approaches indicted the appropriateness of the in vitro methods to identify oncosphericidal treatments of practical significance. Similar heat treatments may also be effective against Taenia saginata and help to reduce occurrence of beef cysticercosis.

TsAg5, a Taenia solium cysticercus protein with a marginal trypsin-like activity in the diagnosis of human neurocysticercosis.

Neurocysticercosis is an endemic parasitic disease caused by Taenia solium larva. Although the mechanism of infection is not completely understood, it is likely driven by proteolytic activity that degrades the intestinal wall to facilitate oncosphere penetration and further infection. We analyzed the publicly available T. solium EST/DNA library and identified two contigs comprising a full-length cDNA fragment very similar to Echinococcus granulosus Ag5 protein. The T. solium cDNA sequence included a proteolytic trypsin-like-domain in the C-terminal region, and a thrombospondin type-1 adherence-domain in the N-terminal region. Both the trypsin-like and adherence domains were expressed independently as recombinant proteins in bacterial systems. TsAg5 showed marginal trypsin-like activity and high sequence similarity to Ag5. The purified antigens were tested in a Western immunoblot assay to diagnose human neurocysticercosis. The sensitivity of the trypsin-like-domain was 96.36% in patients infected with extraparenchymal cysts, 75.44% in patients infected with multiple cysts, and 39.62% in patients with a single cyst. Specificity was 76.70%. The thrombospondin type-1 adherence-domain was not specific for neurocysticercosis.

CpG stimulates protective immunity in Balb/cJ mice infected with larval Taenia crassiceps.

Balb/cJ mice infected in the peritoneal cavity with larval Taenia crassiceps fail to mount a protective immune response. In mice, inflammatory immune responses are believed to control larval reproduction, whereas antibody-mediated responses are believed to be permissive. In the present study, mice were treated with CpG-oligodeoxynucleotides (CpG) to determine whether stimulation of the innate inflammatory response would confer increased resistance to larval growth. Female mice treated with CpG displayed a decrease in mean parasite burden by 54%, while male mice displayed a 73% reduction. Moreover, 5 of 12 CpG-treated male mice completely eliminated all larvae by 9 wk post-infection. In contrast, no female animals were found to be infection free. CpG treatment induced an increase in the transcript levels of tumor necrosis factor-α and inducible nitric oxide synthase (iNOS) from splenocytes and resulted in elevated levels of the proinflammatory molecules monocyte chemotactic protein (MCP)-1, MCP-3, and interleukin-6 at the site of infection. Additionally, CpG administration induced the enhanced recruitment of neutrophils and macrophages to the site of infection. The finding that both neutrophils and macrophages were recruited in significantly higher numbers in the male host as compared to the female host may explain the increased level of protection realized in male animals in response to CpG treatment.

Taenia crassiceps cysticercosis: variations in its parasite growth permissiveness that encounter with local immune features in BALB/c substrains.

This study describes the first days of Taenia crassiceps infection in BALB/c substrains, BALB/cAnN and BALB/cJ, using two stocks of the same strains which were kept in different animal facilities, conventional and pathogen-free conditions, respectively. This study shows that parasite growth restriction shown by conventional BALB/cJ mice changed to parasite growth permissiveness when pathogen-free BALB/cJ mice were used. In addition, the higher number of macrophages, NK cells and intraperitoneal level of IFN-gamma found in the conventional restrictive BALB/cJ substrain vanished when the permissiveness to the parasite growth increased. No differences were found in DNA sequences of parasites collected before and after the change in the permissiveness to parasite growth which favors the possibility that the observed modifications could be due to changes in the murine strains and/or their maintenance conditions.

Chorionic gonadotropin hormone receptors on Taenia solium and Taenia crassiceps cysticerci in culture.

Hormones play a significant role in murine Taenia crassiceps cysticercosis, and they may also participate in the susceptibility to Taenia solium cysticercosis. In the present study, in vitro effects are reported for human chorionic gonadotropin (hCG) on the larval stages of T. crassiceps (WFU strain) and T. solium. Our results reveal the presence of receptors for hCG in different developmental phases of both cultured parasites. On day 30, both taeniid species had the highest percentage of receptors in the neck, strobila, and suckers, but these receptors decreased by day 60, delimiting the segments and the exterior of the developing proglottids in T. solium. At the same time, there was a large number of hCG receptors in the area of the presumptive cirrus organ and in calcareous corpuscles within the parenchyma. This is the first report detecting receptors for hCG on different larval stages of T. crassiceps and T. solium. A direct effect of hCG could be recognized by the cysticerci as a factor contributing to the growth and development of T. crassiceps and T. solium cysticerci, respectively.

The key steroidogenic enzyme 3beta-hydroxysteroid dehydrogenase in Taenia solium and Taenia crassiceps (WFU).

Larval and adult stages of Taenia solium and Taenia crassiceps WFU strain were analyzed by histochemical and biochemical methods to determine the existence of steroid pathways. The presence of the key enzyme 3beta-hydroxisteroid-dehydrogenase (3beta-HSD) was examined in frozen sections of cysticerci obtained from mice and segments of tapeworms obtained from the intestine of hamsters. 3beta-HSD activity was detected by nitroblue-tetrazolium products after incubation with dehydroepiandrosterone, androstendiol, or pregnenolone. Tapeworm tissues exhibited 3beta-HSD activity in the subtegumentary areas of the neck and immature proglottids following incubation with androstendiol, as well as surrounding the testes in mature proglottids. T. solium cysticerci exhibited 3beta-HSD activity in the subtegumentary tissues. The synthesis of steroid hormones involving the activity of 3beta-HSD was studied in cysticerci or tapeworms incubated in the presence of tritiated steroid precursors. The culture media were analyzed by thin layer chromatography and showed synthesis of androstendiol, testosterone, and 17beta-estradiol by cysticerci, androstendiol, and 17beta-estradiol by tapeworms. The results strongly suggest the activity of 3beta-HSD in taeniid parasites that have at least a part of the enzymatic chain required for androgen and estrogen synthesis and that the enzymes are present in the larval stage and from the early strobilar stages to the mature proglottids.

Preferential growth of Taenia crassiceps cysticerci in female mice holds across several laboratory mice strains and parasite lines.

A retrospective study of our 14-yr records on experimental Taenia crassiceps (ORF(fast) line) cysticercosis (n = 1,198) shows that in 16 of 17 different mice strains, female mice are more frequently infected and carry larger individual parasite loads than males. However, sexual differences in parasite loads significantly varies between strains in relation to their different genetic backgrounds (BALB > C57Bl = OTHERS > C3H). The coefficient of variation in all female mice is significantly smaller than that of all males, an indication of males' more potent, but erratically effective, restraint of cysticercus growth. Similar positive growth bias for female mice is shown by other lines of cysticerci, i.e., HYG(slow) and WFU(slow). These results contravene the usual expectation of female hosts being more resistant than males to parasite infections, and they point to the multiple factors that combined determine sex related differences of mice to experimental cysticercosis infection.

Human and porcine neurocysticercosis: differences in the distribution and developmental stages of cysticerci.

OBJECTIVE: To describe and compare the clinical impacts of neurocysticercosis (NC) caused by Taenia solium in humans and pigs. METHODS: Comparative study of the brains of 16 asymptomatic pigs and 35 human NC cases (15 asymptomatic and 20 symptomatic). RESULTS: In humans, cysticerci were more frequently located in the ventricles and subarachnoid space at the base of the brain (11.8%vs. 1.6%; P = 0.001 and 25.9%vs. 0%; P < 0.0001, respectively) while in pigs, cysticerci were more frequently found in the parenchyma (44.4%vs. 7.6%; P < 0.0001). In human brains, 75.9% of the cysticerci were calcified, while in pigs all cysticerci were in the vesicular stage. CONCLUSION: The duration of infection and the host-parasite relationship (such as immune reactivity and brain haemodynamics) differ between humans and pigs. This may account for the different distribution and stage of the cysticerci among humans and pigs.

Treatment with dehydroepiandrosterone in vivo and in vitro inhibits reproduction, growth and viability of Taenia crassiceps metacestodes.

The aim of this work was to explore the effect of dehydroepiandrosterone (DHEA) on the establishment, growth and reproduction of the metacestode stage of the tapeworm Taenia crassiceps, both in vivo and in vitro. Administration of DHEA prior to infection in mice of both sexes reduced the parasite load by 50% compared with untreated mice. This protective effect was not associated with the immune response, since there was no effect of DHEA treatment on mRNA levels of IL-2, IFN-gamma, IL-4 or IL-10. DHEA treatment of infected mice increased androgen receptor expression in splenocytes of both sexes. Moreover, in vitro treatment of T. crassiceps with DHEA reduced reproduction, motility and viability in a dose- and time-dependent fashion. Results indicate that DHEA has strong negative direct modulatory effects on murine cysticercosis. We suggest the use of hormonal-analogues for protective purposes as a therapeutic approach to prevent murine cysticercosis.

Comparisons between scolex and membrane antigens of Cysticercus fasciolaris and Cysticercus cellulosae larvae for immunodiagnosis of neurocysticercosis.

The antigen source for enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunotransfer blot for neurocysticercosis is generally Taenia solium. A comparison of the membrane and scolex extracts of Cysticercus cellulosae and Cysticercus fasciolaris (larval stage of Taenia taeniaeformis) for the immunodiagnosis of neurocysticercosis has been performed. C. fasciolaris cysts were produced experimentally in rat liver. C. cellulosae was obtained from muscle of infected pigs. The antigen extracts of membrane and scolex were compared using ELISA in 50 patients and 50 control participants to detect immunoglobulin (Ig) G or IgM antibodies. Proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were immunoprobed using pooled and individual sera. The gold standard for diagnosis was visualization of scolex in ring lesions by magnetic resonance imaging or computed tomography scans. ELISA for IgG antibodies using C. fasciolaris membrane had the highest sensitivity of 94%. Specificity ranged from 78% to 90%. Immunoreactive bands common to all 4 antigens were seen between 60 and 70 kDa and 40 and 45 kDa. The presence of comparative antigenic bands between human and rat pathogens provides convincing evidence for use of C. fasciolaris antigens for immunodiagnostic procedures. The antigen can be produced in small animals in standardized laboratory conditions within 60 days.

Human cysticercosis and Indian scenario: a review.

Cysticercosis, caused by Taenia solium larva is a major public health problem,especially in the developing world and neurocysticercosis (NCC) is considered to be the most common parasitic infestation of the central nervous system. NCC is identified as the single most common cause of community acquired active epilepsy; 26.3% to 53.8% active epilepsy cases in the developing world including India and Latin America are due to NCC.It is also becoming more common in the developed world because of increased migration of people with the disease or Taenia solium carriers and frequent travel to the endemic countries. It is estimated that three quarters of the estimated 50 million people with active epilepsy live in the poor countries of the world. Recent Indian studies using neuroimaging techniques suggest that the disease burden in India surpasses many other developing countries. Hence it is important to know the epidemiology,pathogenesis and diagnostic criteria so as to assess the disease burden and adopt interventional strategies for its control.Literature search was done for this review with special emphasis on Indian studies to create awareness about the disease in India,since cysticercosis is preventable and potentially eradicable.

A new highly effective anticysticercosis vaccine expressed in transgenic papaya.

The use of transgenic plants as new antigen-delivery systems for subunit vaccines has been increasingly explored. We herein report progress toward a papaya-based vaccine against cysticercosis. Synthetic peptides (KETc1, KETc12, KETc7) were successfully expressed in 19 different transgenic papaya clones and found to be immunogenic. Complete protection against cysticercosis was induced with the soluble extract of the clones that expressed the higher levels of transcripts in up to 90% of the immunized mice. This study represents a key step towards the development of a more effective, sustainable and affordable oral subunit vaccine against human and pig cysticercosis.

Development of Taenia asiatica cysticerci to infective stage and adult stage in Mongolian gerbils.

The development of metacestodes and adult worms of Taenia asiatica in Mongolian gerbils (Meriones unguiculatus) were observed. Cysticerci were recovered from gerbils subcutaneously injected with hatched oncospheres. The recovery rate ranged from 0.1 to 3.2%. No cysticerci were recovered from the orally inoculated gerbils. The infectivity of the cysticerci recovered at 48 weeks post-infection was evaluated. Tapeworms were recovered on day 14 post-infection from the small intestine of 5 of 11 gerbils, with a recovery rate of 27% (6 worms recovered/22 worms inoculated). Three and four adult worms were recovered from two human volunteers who ingested five cysticerci after 4 months post-infection. In worms recovered from gerbils, segmentation and genital primordia in the posterior proglottids and hooklets in the residual rostellum were observed. The results indicate that gerbils can serve as an alternative intermediate host and that partial development of the adult worm stage occurs in gerbils.

[Effect of gamma-interferon on hepatic granuloma formation in mice infected by cysticerci of Taenia saginata asiatica].

Immunohistochemical streptavidin biotin-peroxidase complex method was used to investigate the effect of gamma-interferon (IFN-gamma) on the hepatic granuloma formation and liver fibrosis in mice infected with Taenia saginata in Duyun area of Guizhou Province. The results reveal contrary relation between the level of IFN-gamma in the liver and the degree of liver fibrosis (p<0.01). The injection of IFN-gamma considerably decreased (p<0.01) the area and size of granuloma (p<0.01).

Development of Taenia saginata asiatica metacestodes in SCID mice and its infectivity in human and alternative definitive hosts.

Development of Taenia saginata asiatica metacestodes in SCID mice, and its infectivity in humans, golden hamsters, and Mongolian gerbils as alternative definitive hosts, were investigated. Cysticerci were recovered from SCID mice that were subcutaneously injected with hatched oncospheres of T. s. asiatica. The morphological changes of metacestodes were observed. The recovered cysticerci were fed to gerbils, hamsters and humans, to check for their infectivity. Tapeworms were recovered from gerbils and hamsters fed with 20 to 45 week-old cysticerci, and proglottids excretions were observed in human volunteers fed with 45 week-old cysticerci. However, no tapeworms were recovered from gerbils fed with 10 week-old cysticerci. Our results suggest that T. s. asiatica oncospheres needed more than 20 weeks to develop to maturity in SCID mice to be infective to both their natural and alternative definitive hosts.