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After almost 50 years of praziquantel (PZQ) research, Park and Marchant (Trends Parasitol 36:182–194, 2020) described the Ca++-permeable transient receptor potential (TRP) channel Sm.TRPMPZQ in Schistosoma mansoni as target of PZQ. Here we describe the deadly cascade in schistosomes which is induced by the (R)-PZQ enantiomer that includes contemporaneous stereoselective activation of Sm.TRPMPZQ-mediated Ca++ influx, disturbed Ca++ homeostasis, Ca++-dependent spastic paralysis, and Ca++- and PZQ-dependent disruption of parasitic teguments. Under normal conditions, there is a reversible balance between bilayer, isotropic, and HII phases in biological membranes (Jouhet 2013). In vitro, we could observe an irreversible but not stereoselective transition to the HII phase in liposomes consisting of phosphatidylethanolamine (PE) and phosphatidylserine (PS), two naturally occurring phospholipids in schistosomes, by the concerted action of Ca++ and PZQ (Harder 2013). HII structures are a prerequisite for induction of fusion processes (Jouhet 2013), which, indeed, become visible as blebs, vacuolation processes, and large balloon-like surface exudates in a large variety of PZQ-sensitive parasitic flukes and cestodes after PZQ treatment. These tegument damages are irreversible. As homologs of Sm.TRPMPZQ are also present in the other trematodes S. japonicum, S. haematobium, or Clonorchis sinensis and cestodes Taenia solium, Echinococcus multilocularis, or Hymenolepis microstoma (Park and Marchant, Trends Parasitol 36:182–194, 2020), it is suggested that a similar deadly cascade will be operating generally in PZQ-sensitive parasites.

Summary The mouse bile duct tapeworm Hymenolepis microstoma, is a potentially zoonotic species with a wide variety of reported definitive hosts of rodent genera. In the present study the occurrence of H. microstoma in free-living small mammals in selected areas of Slovakia and the retrospective analysis of epidemiological data published in Slovakia were performed. Hymenolepis microstoma was detected in two animal species, the common shrew (Sorex araneus) and the European hamster (Cricetus cricetus) of 186 small mammals examined from two ecosystems, urban and natural ecosystem of national park. No mention about the presence of this parasite in Slovakia in the past was found following a bibliographical search. Partial sequences of the nuclear paramyosin gene showed the shrew isolate placed in a subclade together with H. microstoma from Portugal, with high bootstrap value for its differentiation from the sister species Hymenolepis nana. Similarly, the analysis of the nuclear ribosomal ITS region placed the hamster isolate in the cluster composed of H. microstoma from Australia, Spain and Portugal. The Slovak isolate was the most distinctive sample among available H. microstoma, differing in 1.4 – 1.9% of nucleotides from the remaining isolates. The difference (seven of 17 nucleotide positions) was partially due to indel polymorphisms associated with two and five nucleotides. To our knowledge, these are the first reports of H. microstoma in Central Europe and also the first record of infection in the common shrew. A recently indicated zoonotic potential of H. microstoma along with a possibility of its direct transmission between animals and/or humans without the need of intermediate hosts pose a public health concern in contaminated areas of Slovakia. The use of molecular techniques may substantially facilitate more thorough understanding of the epidemiological situation of H. microstoma and related tapeworms in various ecosystems of the country.

Numerous experimental studies have been conducted on the rodent tapeworm, Hymenolepis microstoma. In contrast, less is known about the life-cycle and immunobiology of the zoonotic dwarf tapeworm, Hymenolepis nana. However, H. nana appears to be unique in that; (i) it can complete its entire life-cycle within a single mammalian host, and (ii) cysticercoids that develop in beetle intermediate hosts are tailed, while those that develop in the intestinal tissue of mammals are tailless. This is in contrast to all other Hymenolepis spp., which only appear to develop tailed cysticercoids in beetles or experimentally infected immunodeficient rodents. Even though H. microstoma and H. nana are phylogenetically much closer to each other than to Hymenolepis diminuta, when mice with severe combined immunodeficiency (SCID) were inoculated with H. microstoma eggs, hatched oncospheres invaded the intestinal tissue and developed into infective tailed cysticercoids in approximately 11 days. Therefore, H. nana appears to be truly unique in its ability to develop tailed cysticercoids in beetles and tailless cysticercoids in mammals. These unique evolutionary characteristics are discussed in relation to other cyclophyllidean cestodes, including Taenia solium and Echinococcus spp.

Most parasitic flatworms go through different life stages with important physiological and morphological changes. In this work, we used a transcriptomic approach to analyze the main life-stages of the model tapeworm Hymenolepis microstoma (eggs, cysticercoids, and adults). Our results showed massive transcriptomic changes in this life cycle, including key gene families that contribute substantially to the expression load in each stage. In particular, different members of the cestode-specific hydrophobic ligand-binding protein (HLBP) family are among the most highly expressed genes in each life stage. We also found the transcriptomic signature of major metabolic changes during the transition from cysticercoids to adult worms. Thus, this work contributes to uncovering the gene expression changes that accompany the development of this important cestode model species, and to the best of our knowledge represents the first transcriptomic study with robust replicates spanning all of the main life stages of a tapeworm.

Penelitian ini untuk mengetahui golongan senyawa metabolit sekunder dari ekstrak daun miana (Coleus blumei. Benth) yang memiliki aktivitas anticestoda. Daun miana kering diekstraksi dengan metode yang sesuai untuk mendapatkan golongan senyawa metabolit sekunder alkaloid, flavonoid, tanin, dan steroid. Aktivitas anticestoda diukur dengan menghitung waktu kematian cacing Hymenolepis microstoma pada setiap golongan metabolit sekunder konsentrasi 10%. Hasil penelitian menunjukkan tanin memiliki aktivitas anticestoda yang kuat yang tidak berbeda dengan praziquatel sebagai anthelmintik komersial. Akivitas anticestoda flavonoid mirip dengan tanin akan tetapi aktivitasnya masih dibawah praziquatel. Alkaloid dan steroid memiliki aktivitas anticestoda yang lebih rendah dibandingkan dengan tanin dan flavonoid. Hasil penelitian ini membuktikan bahwa tanin sebagai senyawa metabolit sekunder yang paling aktif sebagai anticestoda dibandingkan flavonoid, alkaloid, dan steroid.

The oncosphere larvae of tapeworms cyclically extend and retract their hooks during the penetration of the intestine of their intermediate hosts. The mechanisms regulating these movements are essentially unknown, in part due to the biohazardous nature of oncospheres from human pathogens. In this work, we standardized a method for the analysis of motility of hatched oncospheres (hexacanths) of the model tapeworm Hymenolepis microstoma. We used this assay to explore the relevance of protein kinases C (PKC) and A (PKA) in these processes. Pharmacological inhibition of the PKC pathway resulted in impaired larval motility. On the other hand, the PKA inhibitor H-89 potently blocked larval motility, as well as the motility of other life stages, although other inhibitors of the PKA pathway were not effective. This work represents the first study of the mechanisms that regulate the motility of oncospheres, and provides a path for further exploration.

Hymenolepidid cestodes of synanthropic rodents represent a risk for public health. In order to describe the occurrence of hymenolepidids in children and the role of rodents as a potential source of infection, we conducted a morphological and molecular survey on cestodes in two rural villages from Yucatan, Mexico. One hundred and thirty-five stool samples from children (64 from Paraiso and 71 from Xkalakdzonot), 233 Mus musculus (159 from Paraiso and 74 from Xkalakdzonot) and 125 Rattus rattus (7 from Paraiso and 118 from Xkalakdzonot) were analyzed for the presence of cestodes. Three hymenolepidid species were identified morphologically: Hymenolepis nana in 7.8% of children from Paraiso, Hymenolepis microstoma in 4.4% of M. musculus from Paraiso and Hymenolepis diminuta in 15.3% of R. rattus from Xkalakdzonot. The molecular characterization and phylogenetic analysis based on mitochondrial cytochrome c subunit 1 (CO1) gene and ribosomal internal transcribed spacer 1 (ITS1) region, confirmed the identity of the three cestodes isolated from Yucatan. Phylogeny of the CO1 gene identified intraspecific genetic differences within H. nana ranging from 0 to 5%, in H. microstoma from 0 to 0.4%, and in H. diminuta ranged from 0 to 6.5% which suggests, the presence of complex species within H. nana and H. diminuta infecting humans and rodents, as reported by other authors. Based on the morphological and molecular results, and the epidemiological evidence, infections with H. nana suggest a non-zoonotic transmission; however, the presence of H. microstoma and H. diminuta in synanthropic rodents serve as a possible source for human infection.

The Cyclophyllidea is the most diverse order of tapeworms, encompassing species that infect all classes of terrestrial tetrapods including humans and domesticated animals. Available phylogenetic reconstructions based either on morphology or molecular data lack the resolution to allow scientists to either propose a solid taxonomy or infer evolutionary associations. Molecular markers available for the Cyclophyllidea mostly include ribosomal DNA and mitochondrial loci. In this study, we identified 3641 single-copy nuclear coding loci by comparing the genomes of Hymenolepis microstoma, Echinococcus granulosus and Taenia solium. We designed RNA baits based on the sequence of H. microstoma, and applied target enrichment and Illumina sequencing to test the utility of those baits to recover loci useful for phylogenetic analyses. We captured DNA from five species of tapeworms representing two families of cyclophyllideans. We obtained an average of 3284 (90%) of the targets from the test samples and then used captured sequences (2 181 361 bp in total; fragment size ranging from 301 to 6969 bp) to reconstruct a phylogeny for the five test species plus the three species for which genomic data are available. The results were consistent with the current consensus regarding cyclophyllidean relationships. To assess the potential for our method to yield informative genetic variation at intraspecific scales, we extracted 14 074 single nucleotide polymorphisms (SNPs) from alignments of four Arostrilepis macrocirrosa and two A. cooki and successfully inferred their relationships. The results showed that our target gene tools yield data sets that provide robust inferences at a range of taxonomic scales in the Cyclophyllidea.

Intestinal helminths induce immune suppressive responses thought to regulate inflammatory diseases including allergies and autoimmune diseases. This study was designed to evaluate whether helminthic infections suppress the natural development of systemic lupus erythematosus (SLE) in NZBWF1 mice. Infection of NZBWF1 SLE-prone mice with two nematodes failed to establish long-lasting settlement. However, the Hymenolepis microstoma (Hm) rodent tapeworm successfully established long-term parasitization of NZBWF1 mice and was used to evaluate the suppressive effects of helminth infection. Ten-month-old NZBWF1 mice developed symptoms including autoantibody generation, proteinuria, glomerular histopathology, and splenomegaly, but mice infected with Hm at 2 months of age did not show any clinical signs. Furthermore, infection with Hm reduced lymphocyte activation and increased regulatory T cells in the spleen and mesenteric lymph nodes. These results indicate that infection with Hm protects NZBWF1 mice from naturally developing SLE and suggest that pathological immunity is attenuated, presumably because of the induction of regulatory T cells.

The Wnt/beta-catenin pathway has many key roles in the development of animals, including a conserved and central role in the specification of the primary (antero-posterior) body axis. The posterior expression of Wnt ligands and the anterior expression of secreted Wnt inhibitors are known to be conserved during the larval metamorphosis of tapeworms. However, their downstream signaling components for Wnt/beta-catenin signaling have not been characterized. In this work, we have studied the core components of the beta-catenin destruction complex of the human pathogen Echinococcus multilocularis, the causative agent of alveolar echinococcosis. We focused on two Axin paralogs that are conserved in tapeworms and other flatworm parasites. Despite their divergent sequences, both Axins could robustly interact with one E. multilocularis beta-catenin paralog and limited its accumulation in a heterologous mammalian expression system. Similarly to what has been described in planarians (free-living flatworms), other beta-catenin paralogs showed limited or no interaction with either Axin and are unlikely to function as effectors in Wnt signaling. Additionally, both Axins interacted with three divergent GSK-3 paralogs that are conserved in free-living and parasitic flatworms. Axin paralogs have highly segregated expression patterns along the antero-posterior axis in the tapeworms E. multilocularis and Hymenolepis microstoma, indicating that different beta-catenin destruction complexes may operate in different regions during their larval metamorphosis.

Background Tapeworms are agents of neglected tropical diseases responsible for significant health problems and economic loss. They also exhibit adaptations to a parasitic lifestyle that confound comparisons of their development with other animals. Identifying the genetic factors regulating their complex ontogeny is essential to understanding unique aspects of their biology and for advancing novel therapeutics. Here we use RNA sequencing to identify up-regulated signalling components, transcription factors and post-transcriptional/translational regulators (genes of interest, GOI) in the transcriptomes of Larvae and different regions of segmented worms in the tapeworm Hymenolepis microstoma and combine this with spatial gene expression analyses of a selection of genes. Results RNA-seq reads collectively mapped to 90% of the > 12,000 gene models in the H. microstoma v.2 genome assembly, demonstrating that the transcriptome profiles captured a high percentage of predicted genes. Contrasts made between the transcriptomes of Larvae and whole, adult worms, and between the Scolex-Neck, mature strobila and gravid strobila, resulted in 4.5–30% of the genes determined to be differentially expressed. Among these, we identified 190 unique GOI up-regulated in one or more contrasts, including a large range of zinc finger, homeobox and other transcription factors, components of Wnt, Notch, Hedgehog and TGF-β/BMP signalling, and post-transcriptional regulators (e.g. Boule, Pumilio). Heatmap clusterings based on overall expression and on select groups of genes representing ‘signals’ and ‘switches’ showed that expression in the Scolex-Neck region is more similar to that of Larvae than to the mature or gravid regions of the adult worm, which was further reflected in large overlap of up-regulated GOI. Conclusions Spatial expression analyses in Larvae and adult worms corroborated inferences made from quantitative RNA-seq data and in most cases indicated consistency with canonical roles of the genes in other animals, including free-living flatworms. Recapitulation of developmental factors up-regulated during larval metamorphosis suggests that strobilar growth involves many of the same underlying gene regulatory networks despite the significant disparity in developmental outcomes. The majority of genes identified were investigated in tapeworms for the first time, setting the stage for advancing our understanding of developmental genetics in an important group of flatworm parasites. Electronic supplementary material The online version of this article (10.1186/s13227-018-0110-5) contains supplementary material, which is available to authorized users.

Parasite life history may differ during coinfection compared to single infections, and the order of infection may be an important predictor of life history traits. We subjected laboratory mice (Mus musculus) to single and coinfections with Heligmosomoides bakeri and Hymenolepis microstoma and measured life history traits of worms and also hepatobiliary and morphological responses by the host. We found that fewer H. bakeri larvae established, and adult worms were shorter and produced fewer eggs during a coinfection where H. microstoma occurred first. H. microstoma grew more and released more eggs after simultaneous inoculation of both parasites compared to a single H. microstoma infection, despite similar worm numbers. Mouse small intestine mass, but not length, varied with coinfection and bile duct mass was largest when H. microstoma was given alone or first. Mouse serum alkaline phosphatase levels were greatest for mice infected with H. microstoma only but did not vary with number of scolices; no change in mouse serum alanine transaminase levels was observed. Overall, the order of coinfection influenced life history traits of both H. bakeri and H. microstoma, but changes in survival, growth, and reproduction with order of inoculation were not consistent between the two parasites.

A 9 year-old male, neutered cat with a history of a sudden onset of lethargy, anorexia and respiratory distress was presented in a veterinary practice in Lucca, Italy. A clinical examination revealed that the cat was severely dehydrated, and had pale mucous membranes and tachypnoea. No pain or discomfort was detected at the time of physical examination. The cat was administered fluids, antibiotics and supportive therapy, but died overnight. The owner of the cat requested for a post mortem examination to be conducted. At necropsy, acephalic structures, consistent with proliferative tapeworm (cestode) larvae, were detected in the thoracic cavity on pleural surfaces. As these larvae could not be identified to genus or species by microscopy, a PCR-based sequencing-phylogenetic approach was used. Part of the cytochrome c oxidase subunit 1 gene was PCR-amplified from genomic DNAs from five individual larvae and sequenced; all five sequences obtained were identical. This consensus sequence was aligned (over 355 nucleotide positions) with homologous sequences representing a range of cestodes (including Echinococcus granulosus, Echinococcus multilocularis, Hymenolepis microstoma, Mesocestoides spp. and Taenia saginata) from previously published studies and then subjected to phylogenetic analysis. The sequence representing the larval cestode from the affected cat grouped, with strong statistical support, with those representing Mesocestoides corti and Mesocestoides lineatus. Therefore, a definitive diagnosis of pleural proliferative larval mesocestoidiasis could be made. This study illustrates the value of using molecular tools to directly assist clinical and pathological investigations of cestodiases of animals.

SUMMARY Characterization of the first tapeworm genome, Echinococcus multilocularis, is now nearly complete, and genome assemblies of E. granulosus, Taenia solium and Hymenolepis microstoma are in advanced draft versions. These initiatives herald the beginning of a genomic era in cestodology and underpin a diverse set of research agendas targeting both basic and applied aspects of tapeworm biology. We discuss the progress in the genomics of these species, provide insights into the presence and composition of immunologically relevant gene families, including the antigen B- and EG95 ⁄ 45W families, and discuss chemogenomic approaches toward the development of novel chemotherapeutics against cestode diseases. In addition, we discuss the evolution of tapeworm parasites and introduce the research programmes linked to genome initiatives that are aimed at understanding signalling systems involved in basic host–parasite interactions and morphogenesis.

Little is known about the efficacy of cysteine proteinases (CP) as anthelmintics for cestode infectionsin vivo.Hymenolepis microstomais a natural parasite of house mice, and provides a convenient model system for the assessment of novel drugs for anthelmintic activity against cestodes. The experiments described in this paper indicate that treatment ofH. microstomainfections in mice with the supernatant of papaya latex (PLS), containing active cysteine proteinases, is only minimally efficacious. The statistically significant effects seen on worm burden and biomass showed little evidence of dose dependency, were temporary and the role of cysteine proteinases as the active principles in PLS was not confirmed by specific inhibition with E-64. Worm fecundity was not affected by treatment at the doses used. We conclude also that thisin vivohost–parasite system is not sensitive enough to be used reliably for the detection of cestocidal activity of compounds being screened as potential, novel anthelmintics.

The dynamics of intestinal mucosal mast cells and the major mucosal mast cell protease were followed during the course of laboratory infections of mice with Hymenolepis diminuta and H. microstoma. The effects of the drug cyclosporin A (CsA), which is both immunosuppressive and selectively anthelmintic depending upon dose regime, were determined. In H. diminuta infections worm expulsion occurred around day 9 and coincided with peak mastocytosis and peak mMCP-I concentrations in tissues and serum. Immunosuppressive treatment with CsA prevented worm expulsion, permitting some individuals to reach maturity, and abrogated mast cell proliferation and mMCP-I production and release. By contrast, H. microstoma infections persisted for 64 days in spite of a considerable mastocyosis in both intestine and bile duct tissues accompanied by a high level of mMCP-I in tissues and serum. A subimmunosuppressive regime of CsA had only limited effects on worms and mast cell numbers and activity. Together these data shed light on the variable mast cell response to gastrointestinal infections and on the potential significance of parasite location in evasion of mast cell action. Use of CsA reveals the contributions of both T cell-dependent mechanisms, including mast cell proliferation and activation, and T cell-independent events in regulating intestinal helminth infections.

Hymenolepis microstoma (Cestoda), Echinostoma caproni, and Schistosoma mansoni (Digenea) were exposed to benzimidazoles to determine the influence of the drugs on the secretion of glycoconjugates that protect the worms' surface. Worms were obtained from mice treated with mebendazole or albendazole, and the glycoconjugates were localized in the parasite tissues by cytochemistry using lectin-gold conjugates. Events leading to the death of H. microstoma and E. caproni extended over a medication period for at least 2-3 days, and the following interrelated phases were discernible. Upon depolymerization of the microtubules the tegumentary cytons continued to synthesize glycoconjugates for up to about 24 h. Vesicles containing the glycans accumulated in the cytons, but their microtubule-based transport to the distal tegument was inhibited. At about 1 day the Golgi complex became fragmented and the production of glycans sharply declined. As a consequence of this and an ongoing turnover of the surface coat the contents of glycoconjugates in the distal tegument decreased. Similar effects were produced by vinblastine and colchicine in vitro. In contrast, benzimidazole treatment of S. mansoni, which is reportedly inefficacious, did not alter the replenishment of the surface glycoconjugates. Diminution of the coating with glycoconjugates of the surface of drug-sensitive species constitutes a secondary effect of benzimidazoles that might, synergistically with immune mechanisms of the host, enhance the expulsion of the worms.

Three hymenolepidid tapeworms, Hymenolepis diminuta, H. nana and H. microstoma, are commonly maintained in laboratory rodents and used in many experimental model systems of tapeworm infections. We examined partial sequences from the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene and nuclear ribosomal internal transcribed spacer 2 (ITS2) sequences to infer phylogenetic relationships of the 3 hymenolepidid species. Parts of the CO1 gene and ITS2 were amplified by PCR and sequenced directly. The CO1 gene sequence obtained was the same in length (391 bp) among all specimens. In the case of ITS2, however, several insertions and deletions were detected (671–741 bp) not only among species but also between an American isolate and a Japanese isolate of H. diminuta. Percentage nucleotide differences between H. diminuta and H. microstoma, or H. diminuta and H. nana were 16·6–18·2% for the CO1 gene and 21·3–22·9% for ITS2. The differences in both sequences between H. microstoma and H. nana were about 14%. Phylogenetic trees inferred from both of the nucleotide sequences showed similar topology, and suggest that H. diminuta may have diverged from the common ancestral line the earliest, and that H. nana is closer to H. microstoma than to H. diminuta.

Embelia schimperi Vatke, belonging to the family Myrsinaceae, is used among the traditional Masai people of Tanzania and Kenya since it is believed to eliminate adult Taenia saginata, the beef tapeworm. In the present study, the anthelmintic effect of an extract of the dried fruits of Embelia schimperi was studied in experimental parasite/rodent models. In two experiments, rats with 10 adult tapeworms of Hymenolepis diminuta were treated with a diammonium salt of embelin (DE), isolated from the fruits. Significant lower numbers and total worm biomass of Hymenolepis diminuta were observed in rats treated with 100 mg DE/kg. Furthermore, clear indications of the occurrence of destrobilation was observed in faeces after treatment and in 16% of the worms found at autopsy. The killing effect shown in vivo was corroborated by in vitro studies, which showed that all adult Hymenolepis diminuta were killed when incubated in a culture medium containing as little as 0.08 mg DE/ml. No significant in vivo effect of DE was observed against Hymenolepis microstoma, the trematode Echinostoma caproni and the nematode Heligmosomoides polygyrus in mice, although the worms could be killed in vitro. These results indicate that the crushed seeds of Embelia schimperi taken orally by the Masai people indeed have an anthelmintic effect against human intestinal tapeworms.

Tapeworms (Cestoda) cause neglected diseases that can be fatal and are difficult to treat, owing to inefficient drugs. Here we present an analysis of tapeworm genome sequences using the human-infective species Echinococcus multilocularis, E. granulosus, Taenia solium and the laboratory model Hymenolepis microstoma as examples. The 115- to 141-megabase genomes offer insights into the evolution of parasitism. Synteny is maintained with distantly related blood flukes but we find extreme losses of genes and pathways that are ubiquitous in other animals, including 34 homeobox families and several determinants of stem cell fate. Tapeworms have specialized detoxification pathways, metabolism that is finely tuned to rely on nutrients scavenged from their hosts, and species-specific expansions of non-canonical heat shock proteins and families of known antigens. We identify new potential drug targets, including some on which existing pharmaceuticals may act. The genomes provide a rich resource to underpin the development of urgently needed treatments and control. Fil: Tsai, Isheng J.. Wellcome Trust Genome Campus; Estados Unidos. University of Miyazaki; Japón Fil: Zarowiecki, Magdalena. Wellcome Trust Genome Campus; Estados Unidos Fil: Holroyd, Nancy. Wellcome Trust Genome Campus; Estados Unidos Fil: Garciarrubio, Alejandro. Universidad Nacional Autónoma de México; México Fil: Sanchez Flores, Alejandro. Wellcome Trust Genome Campus; Estados Unidos. Universidad Nacional Autónoma de México; México Fil: Camicia, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Cucher, Marcela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Kamenetzky, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Macchiaroli, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Rosenzvit, Mara Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentina Fil: Liu, Kan. Chinese Academy of Sciences; República de China Fil: Luo, Xuenong. Chinese Academy of Agricultural Sciences; China Fil: Luo, Yingfeng. Chinese Academy of Sciences; República de China Fil: Nichol, Sarah. Wellcome Trust Genome Campus; Estados Unidos Fil: Paps, Jordi. University of Oxford; Reino Unido Fil: Parkinson, John. University of Toronto; Canadá Fil: Pouchkina Stantcheva, Natasha. Natural History Museum; Reino Unido Fil: Riddiford, Nick. Natural History Museum; Reino Unido Fil: Salinas, Gustavo. Universidad de la República; Uruguay Fil: Wasmuth, James D.. University of Calgary; Canadá Fil: Zamanian, Mostafa. McGill University; Canadá Fil: Zheng, Yadong. Chinese Academy of Agricultural Sciences; China Fil: The Taenia Solium Genome Consortium. No especifica; Fil: Cai, Xuepeng. Chinese Academy of Agricultural Sciences; China Fil: Soberón, Xavier. Universidad Nacional Autónoma de México; México. Instituto Nacional de Medicina Genómica; México Fil: Olson, Peter D.. Natural History Museum; Reino Unido Fil: Laclette, Juan P.. Universidad Nacional Autónoma de México; México Fil: Brehm, Klaus. Universität Würzburg; Alemania Fil: Berriman, Matthew. Wellcome Trust Genome Campus; Estados Unidos

Hymenolepis microstoma, the mouse bile-duct tapeworm, is a classical rodent-hosted model that provides easy laboratory access to all stages of the life cycle. Recent characterisation of its genome has greatly advanced its utility for molecular research, albeit contemporary techniques such as those for assaying gene function have yet to be developed in the system. Here we present research on the development of RNA-mediated gene suppression via RNA interference (RNAi), and on in vitro culture of the enteric, adult phase of the life cycle to support this work. We demonstrate up to 80% quantitative suppression of a Hox transcript via soaking activated juvenile worms with double-stranded RNAs. However, we were unable to achieve segmentation of the worms in culture despite extensive manipulations of the culture media and supplements, preventing functional interpretation. An alternative, in vivo approach to RNAi was also tested by exposing cysticercoids prior to inoculation in mice, but fluorescent labelling showed that the RNAs did not sufficiently penetrate the cyst body and no difference in expression was found between exposed and control groups grown in vivo. Genomic and transcriptomic data revealed that H. microstoma has two orthologs each of Dicer, Drosha and Ago-1-like genes and that expression of one of the Ago-1 genes appears exclusive to germline development, suggesting that two or more independent RNA-mediated pathways are in operation. These studies demonstrate the viability of RNAi in H. microstoma and extend the utility of the model for research in the genomic era.

Tribendimidine has been registered for the treatment of human soil transmitted helminthiases in China. In the model nematode Caenorhabditis elegans it is an agonist of L-subtype nicotinic acetylcholine receptors and therefore shares its mode of action with levamisole and pyrantel. Besides its broad spectrum of nematicidal efficacy, tribendimidine is efficacious against several trematodes and has been attributed to have anti-cestodal effects. However, there are few published data available for the latter. The efficacy of tribendimidine and its nematicidal metabolite deacylated amidantel against Hymenolepis microstoma were examined for their anti-cestodal potential. Doses of 50 and 100mg/kg body weight deacylated amidantel and 10, 25, 50, and 100mg/kg tribendimidine were administered orally on three consecutive days to mice experimentally infected with eight cysticercoids. Necropsy was performed and the worm burdens were determined one day after the last treatment. Furthermore, levamisole was used in combination with tribendimidine (100mg/kg levamisole plus 10 and 25mg/kg tribendimidine, respectively) and alone (50 and 100mg/kg) to investigate any possible interactions of the partner compounds against cestodes. Tribendimidine showed a very high efficacy at dosages of 50mg/kg or higher. Surprisingly, deacylated amidantel led to no reduction of the worm burden in any of the treatments. Combinations of levamisole with tribendimidine did not augment the effects of tribendimidine alone and as expected levamisole alone also showed no anti-cestodal activity. To our knowledge, this study shows for the first time activity of tribendimidine against a cestode in a controlled laboratory study. Due to the excellent cure rates observed here, multiple tribendimidine treatments might be considered as useful scheme for treatments of cestode, nematode and trematode infections although this would significantly increase both costs and management efforts. Moreover, the differences between tribendimidine and deacylated amidantel indicate at least a strong difference in sensitivity of H. microstoma or a strong difference in drug availability.

Tribolium confosum beetles infected with metacestodes of Hymenolepis diminuta, Hymenolepis microstoma , or Hymenolepis nana were used to study the effect of parasitism on carbohydrate metabolism. 13 C NMR in vivo spectra of uninfected and infected T. confusum , fed d -[1- 13 C]glucose for 24 hr, showed resonances due to CH 3 , (CH 2 ) N , and C=C of fatty acids chains, C 1 , C 6 , and C 2-5 of trehalose and C 1 of glycogen. The 13 C NMR spectra of extracts of these beetles confirmed these assignments and revealed additional small peaks from C 1 of α-glucose, C 1 of β-glocose, C 6 of both αand β-glucose, and C 3 of alanine. The 1 H NMR spectra of these extracts showed resonances due to the same compounds and, in addition, resonances from betaine, cholines, succinate, acetate, and lactate. All infected beetles contained less glucose and lactate than uninfected controls. Furthermore, beetles infected with H. diminuta had less trehalose but more glycogen and those infected with H. microstoma had less succinate and acetate than controls.

Background Hymenolepis microstoma (Dujardin, 1845) Blanchard, 1891, the mouse bile duct tapeworm, is a rodent/beetle-hosted laboratory model that has been used in research and teaching since its domestication in the 1950s. Recent characterization of its genome has prompted us to describe the specific strain that underpins these data, anchoring its identity and bringing the 150+ year-old original description up-to-date. Results Morphometric and ultrastructural analyses were carried out on laboratory-reared specimens of the 'Nottingham' strain of Hymenolepis microstoma used for genome characterization. A contemporary description of the species is provided including detailed illustration of adult anatomy and elucidation of its taxonomy and the history of the specific laboratory isolate. Conclusions Our work acts to anchor the specific strain from which the H. microstoma genome has been characterized and provides an anatomical reference for researchers needing to employ a model tapeworm system that enables easy access to all stages of the life cycle. We review its classification, life history and development, and briefly discuss the genome and other model systems being employed at the beginning of a genomic era in cestodology.

Cyclosporin A (CsA) induced significant changes in parasite morphology when administered to mice infected with Hymenolepis microstoma. Gross morphological damage consisted of proglottis swelling and the formation of protuberances from the worm surface, visible with a low-power dissecting microscope, occurring most frequently in the posterior third of the strobila. Gross morphology and ultrastructure were examined further using scanning and transmission electron microscopy. Swollen proglottides exhibited areas covered in small pits and fissures (diameter approximately 1–2 μm) but it was not possible to establish the significance of this damage. The brush-border and distal cytoplasm appeared largely intact although some evidence of swelling of the basal membrane invaginations and possible fluid accumulation was seen in drug-treated TEM sections. The apparent oedematous condition of many of the proglottides from drug-treated mice may indicate that CsA treatment mediates permeability changes in the worm surface membrane but the mechanisms by which this may occur remain to be elucidated. The effects of CsA on the morphology of H. microstoma correlate with the previously described anthelmintic activity of the drug against this parasite where CsA treatment dramatically reduces worm growth, retards migration into the bile duct and limits parasite survival.

An investigation of the chemotherapeutic effects of 2 anthelmintics, albendazole (ABZ, methyl 5-[propylthio]benzimidazole-2- carbamate) and mebendazole (MBZ, methyl 5-[benzoyl]benzimidazole-2-carbamate), on Hymenolepis microstoma and Hymenolepis diminuta in experimentally infected mice and rats is reported. Single (50 mg/kg) or multiple daily oral doses (50 mg kg-1 day-1 for 3 consecutive days) of MBZ had no effect on H. microstoma; at necropsy, the drug treated mice harbored appreciable numbers of the parasite in the bile duct and biliary passages. ABZ was also inactive when given as a single oral 50 mg/kg dose on day 27 PI. Better results were obtained when ABZ was administered at a dosage of 50 mg kg-1 day-1 for 3 consecutive days; the reduction in worm burden obtained with this treatment regimen was 50%. These results are in marked contrast to those obtained with the same anthelmintics against enteral H. diminuta in rats which succumbed at lower dosages. A review was made of the published reports on the pharmacokinetic behavior of these benzimidazole carbamate anthelmintics and a hypothesis for the inactivity of MBZ against H. microstoma is proposed.

SUMMARYAntineoplastic cyclophosphamide (CY) significantly reduced the survival and the weight ofHymenolepis microstomain mice. Corticosteroid dexamethasone (DEX), on the other hand, did not influence the worm survival and the worms in DEX-treated mice became significantly heavier. Both immunosuppressants abolishedH. microstoma-induced bile duct hypertrophy and submucous enteritis and lowered the number of mast cells (MC) in these regions. CY appeared to be more effective in depleting the bile duct MC whereas DEX seemed to affect more the duodenal MC population.

Immunity to Taiwan Taenia infection in pigs can be stimulated using homologous or heterologous nonviable Taenia oncospheres. This study was designed to determine whether homologous non-viable oncospheres could stimulate immunity to Hymenolepis infection in rodents. Hatched oncospheres were prepared from eggs of Hymenolepis diminuta, Hymenolepis nana , and Hymenolepis microstoma and kept at −70°C for more than 1 month. A mixture of 500 non-viable oncospheres of each tapeworm and complete Freund's adjuvant was injected subcutaneously in four groups of Sprague-Dawley rats or ICR mice one to four times at an interval of 1 week; controls were not immunized. After immunization, each rodent was orally inoculated with three fresh active cysticercoids of H. diminuta or H. microstoma or 500 fresh eggs of H. nana . The animals were then necropsied for adult tapeworms. No rats or mice immunized with non-viable oncospheres of H. diminuta or H. nana were infected by the challenge inoculation. However, 28 of 34 mice immunized with non-viable H. microstoma oncospheres were infected after inoculation with cysticercoids. This study demonstrated complete protection against infection by homologous parasites in rats or mice immunized with non-viable oncospheres of H. diminuta and H. nana , respectively. Repeated immunization may not be required if resistance is stimulated in rodent hosts.

A longitudinal survey of gastro-intestinal parasites was conducted over a 3-year period in remote communities in the north-west of Western Australia where, based on diagnosis by microscopy of faecal samples, Rodentolepis (=Hymenolepis) nana was found to be the most common enteric parasite. In the present study, using molecular tools, we describe the unexpected discovery, of a mixed infection with a second hymenolepidid species, Rodentolepis (=Hymenolepis) microstoma in four of the surveyed individuals. In the absence of any reliable earlier reports we believe this is to be the first instance of the detection of R. microstoma from human hosts. The development of a diagnostic restriction fragment polymorphism has enabled the study of R. microstoma in human populations and will greatly facilitate a more thorough understanding of the epidemiology of this parasite in the future.

Cyclosporin A (CsA) is a widely investigated experimental anti-parasitic drug whose mode of action remains unresolved. The immunosuppressive action of CsA depends on the drug binding to the intracellular receptor cyclophilin (CyP). This study investigates whether complexing of CsA with parasite CyP is equally essential for its anthelmintic action. The correlation between initial cyclosporin-induced damage in vitro and drug binding to parasite CyP has been examined. CsA and the analogues B-5-49, CsH and CsA-acetate all induced similar damage to the tapeworm Hymenolepis microstoma in vitro in incubations between 2 h and 4 days. The initial foci of drug damage were the parasite surface and mitochondria in the syncytium. In a competitive binding assay only B-5-49 displaced [II 3 ]-CsA from either crude parasite cytosolic CyP P or affinity-purified CyP while CsH and CsA-acetate had no effect. 'I'hese data suggest strongly that cyclosporins act on the surfaces of helminth parasites but that drug action does not involve complex formation with CyP An alternative drug-binding site must therefore be identified which may lead to the rational design of novel anthelmintic drugs.