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Purpose: Hymenolepis (Rodentolepis) nana is an enteric tapeworm globally widespread in wild and captive rodents. The survey was carried out in three chinchilla breeding facilities and in one sugar glider breeding facility in Central and Southern Italy., Methods: One hundred and four chinchilla fecal pools and 40 sugar glider fecal pools were collected from cages housing breeding pairs or females with their offspring. Fecal samples were examined with a qualitative and quantitative copromicroscopical approach. Hymenolepis eggs were identified based on morphological and morphometrical features, and the average number of eggs per gram (EPG) of feces was estimated., Results: Hymenolepis nana eggs were detected in 39.42% of chinchilla samples with an average of 16.33 EPG; whereas, all of the sugar glider samples tested positive with an average of 454.18 EPG. Neither helminth eggs nor protozoan cysts/oocysts were detected in any of the breeding facilities., Conclusion: The results clearly show a diffuse parasitism in both chinchillas and sugar gliders, and should be taken into consideration given the rising popularity of these two pet species combined with the zoonotic complications presented by H. nana., (© 2023. The Author(s) under exclusive licence to Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)

Tapeworm infections cause insidious and irreversible effects in the infected individuals and some of them have already shown resistance to available drugs. A search for alternative treatment is urgently required. Phenolic compounds are amongst the most researched natural substances for their medicinal use. The present study aims to determine anthelmintic efficacy of two polyphenols Gallic acid and Catechin against the zoonotic rat tapeworm Hymenolepis diminuta. Both compounds are potent anti-oxidants and play major roles in combating pathogens, while their anthelmintic property according to our knowledge is yet to be explored. The parasite model H. diminuta was procured from intestine of infected rats raised in our laboratory. Two sets of parasites were treated in vitro with 5, 10, 20 and 40 mg/ml concentrations of each Gallic Acid and Catechin separately, another set of parasites were treated with standard dose of Praziquantel in RPMI 1640, while still another set of worms were kept in RPMI 1640 at 37 ± 1 0 C with 1% Dimethyl sulfoxide as control. Motility and structural alterations were the parameters assessed for anthelmintic efficacy of the compounds. After paralysis the worms were processed for morphological, histological, and ultrastructural study and observed under light and electron microscope. Dose-dependent efficacy was observed in both compounds. Shrinkage of suckers, deformed proglottids and architectural alteration of the tegument were observed throughout the body of treated parasites compared to control. Although in terms of time taken for paralysis and mortality Gallic acid was more effective than Catechin, the degree of morphological aberrations caused were almost similar, except histological alteration was more in Catechin treated worms than in Gallic acid. Nevertheless, both Gallic acid and Catechin are suggested to possess anthelmintic efficacy besides other health benefits but extended studies are required to compare their efficacy., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In spite of ongoing eradication programs, helminth infections are still a medical issue in Ghana. For follow-up assessments on the decline of regional helminth infections, historic baseline prevalence values obtained with standardized diagnostic procedures can be helpful. In this retrospective cross-sectional study, real-time PCR targeting the nematodes Ancylostoma spp. (ITS2), Ascaris lumbricoides (ITS1), Enterobius vermicularis (ITS1), Necator americanus (ITS2), Strongyloides stercoralis (18S rRNA) and Trichuris trichiura (18S rRNA), the trematodes Schistosoma spp. (ITS2) as well as the cestodes Hymenolepis nana (ITS1), Taenia saginata (ITS1) and Taenia solium (ITS1) was applied with 2046 DNA eluates from stool samples of Ghanaian children from the Ashanti region collected between 2007 and 2008 in order to retrospectively define prevalence values. The overall prevalence was low with 3.8% ( n = 77) and only 0.1% ( n = 2) double infections with helminths were recorded. The three most frequently detected enteric helminth species comprised 2% S. stercoralis ( n = 41), 0.8% H. nana ( n = 16), and 0.7% N. americanus ( n = 14), while only sporadic infection events were recorded for other helminth species comprising 0.1% E. vermicularis ( n = 2), 0.1% Schistosoma spp. ( n = 2), 0.1% T. saginata ( n = 1) and 0.1% T. trichiura ( n = 1). A. lumbricoides , Ancylostoma spp. and T. solium were not detected at all. In conclusion, the retrospective assessment suggests a low prevalence of enteric helminth infections in Ghanaian children from the Ashanti Region within the assessment period between 2007 and 2008.

This first comprehensive report from Punjab province of India relates to patho-physiological alterations alongwith morpho-molecular characterisation and risk assessment of natural infections of Hymenolepis diminuta and Hymenolepis nana in 291commensal rodents including house rat, Rattus rattus (n=201) and lesser bandicoot rat, Bandicota bangalensis (n=90). Small intestine of 53.61 and 64.95 % rats was found infected with H. diminuta and H. nana , respectively with a concurrent infection rate of 50.86 %. There was no association between male and female rats and H. diminuta and H. nana infections (ᵡ 2 = 0.016 and 0.08, respectively, d.f.= 1, P>0.05), while the host age had significant effect on prevalence of H. diminuta and H. nana (ᵡ 2 = 28.12 and 7.18, respectively, d.f.= 1, P≤0.05) infection. Examination of faecal samples and intestinal contents revealed globular shaped eggs of H. diminuta without polar filaments (76.50 ± 3.01μm x 67.62 ± 2.42 μm), while smaller sized oval eggs of H. nana were with 4 - 8 polar filaments (47.87 ± 1.95 μm x 36.12 ± 3.05 μm). Cestode infection caused enteritis, sloughing of intestinal mucosa, necrosis of villi and inflammatory reaction with infiltration of mononuclear cells in the mucosa and submucosa. Morphometric identification of the adult cestodes recovered from the intestinal lumen was confirmed by molecular characterisation based on nuclear ITS-2 loci which showed a single band of 269 bp and 242 bp for H. diminuta and H. nana , respectively. Pairwise alignment of the ITS-2 regions showed 99.46 % similarity with sequences of H. diminuta from USA and 100 % similarity with sequences of H. nana from Slovakia, Kosice., Competing Interests: Conflict of interest Authors state no conflict of interest., (© 2021 S. K. Brar, N. Singla, L. D. Singla, published by Sciendo.)

We provided the first known evidence of the presence and release of extracellular vesicles in adults of important model tapeworm Hymenolepis diminuta. Two different subtypes have been observed on the surface of the worm and among the secretory products confirmed by several microscopical methods. Proteomic analysis revealed the presence of parasite-specific proteins as well as those of the host in purified extracellular vesicles. Among the protein cargo, we identified potential drug targets, vaccine candidates and H. diminuta antigens. Finally, the protein composition further revealed proteins participating in the endosomal complex required for transport-dependent biogenesis pathway., (Copyright © 2020 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.)

Pithecellobium dulce is distributed in America and Asia where is widely used in traditional medicine. This study describes the bioguided fractionation of the methanol extract (ME) obtained from the P. dulce fruit that showed in vitro activity against Hymenolepis nana ; Artemia salina assay was used to determine toxicity; and the purified compound was computationally analysed to obtain its absorption-distribution-metabolism-excretion-and-toxicity properties (ADMET). The ME and its fractions were more active than praziquantel (PZQ), and the purified compound was characterized as N -malonyl-(+) - tryptophan (NMT). Parasites treated with NMT showed shorter paralysis and death times (5 and 7 min) than those treated with PZQ (15 and 30 min), both used at 20 mg/mL. Toxicity and ADMET prediction results supported the slight-hazardousness and efficacy of the assayed fractions/compound. This is the first report of the antiparasitary activity of both the P. dulce ME and NMT, showing their potential to treat human H. nana infections.

Background: Chromosome-level assemblies are indispensable for accurate gene prediction, synteny assessment, and understanding higher-order genome architecture. Reference and draft genomes of key helminth species have been published, but little is yet known about the biology of their chromosomes. Here, we present the complete genome of the tapeworm Hymenolepis microstoma, providing a reference quality, end-to-end assembly that represents the first fully assembled genome of a spiralian/lophotrochozoan, revealing new insights into chromosome evolution., Results: Long-read sequencing and optical mapping data were added to previous short-read data enabling complete re-assembly into six chromosomes, consistent with karyology. Small genome size (169 Mb) and lack of haploid variation (1 SNP/3.2 Mb) contributed to exceptionally high contiguity with only 85 gaps remaining in regions of low complexity sequence. Resolution of repeat regions reveals novel gene expansions, micro-exon genes, and spliced leader trans-splicing, and illuminates the landscape of transposable elements, explaining observed length differences in sister chromatids. Syntenic comparison with other parasitic flatworms shows conserved ancestral linkage groups indicating that the H. microstoma karyotype evolved through fusion events. Strikingly, the assembly reveals that the chromosomes terminate in centromeric arrays, indicating that these motifs play a role not only in segregation, but also in protecting the linear integrity and full lengths of chromosomes., Conclusions: Despite strong conservation of canonical telomeres, our results show that they can be substituted by more complex, species-specific sequences, as represented by centromeres. The assembly provides a robust platform for investigations that require complete genome representation.

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., (Copyright © 2020 Elsevier B.V. All rights reserved.)

An increase in zoonotic infections in humans in recent years has led to a high level of public interest. However, the extent of infestation of free-living small mammals with pathogens and especially parasites is not well understood. This pilot study was carried out within the framework of the "Rodent-borne pathogens" network to identify zoonotic parasites in small mammals in Germany. From 2008 to 2009, 111 small mammals of 8 rodent and 5 insectivore species were collected. Feces and intestine samples from every mammal were examined microscopically for the presence of intestinal parasites by using Telemann concentration for worm eggs, Kinyoun staining for coccidia, and Heidenhain staining for other protozoa. Adult helminths were additionally stained with carmine acid for species determination. Eleven different helminth species, five coccidians, and three other protozoa species were detected. Simultaneous infection of one host by different helminths was common. Hymenolepis spp. (20.7%) were the most common zoonotic helminths in the investigated hosts. Coccidia, including Eimeria spp. (30.6%), Cryptosporidium spp. (17.1%), and Sarcocystis spp. (17.1%), were present in 40.5% of the feces samples of small mammals. Protozoa, such as Giardia spp. and amoebae, were rarely detected, most likely because of the repeated freeze-thawing of the samples during preparation. The zoonotic pathogens detected in this pilot study may be potentially transmitted to humans by drinking water, smear infection, and airborne transmission.

Hymenolepiasis is considered the most common tapeworm infection throughout the world infecting 50-75 million people. Hymenolepis diminuta infection is not commonly reported in human beings as compared to Hymenolepis nana because it is primarily a parasite of rats and mice. There are few case reports of H. diminuta in the Indian population. To the best of our knowledge, not a single case of coinfection with H. nana and H. diminuta has been reported from India. We present here a rare case report of coinfection of H. nana and H. diminuta in a 4-year-old male child from a semirural area of India who presented with acute and severe colitis., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Tropical Parasitology.)

To investigate the spectrum of rat-borne pathogens circulating in Europe a systematic review spanning across 55 European countries during the years 1995-2016 was performed. The study surveyed viruses, bacteria, macroparasites and unicellular eukaryotes (protozoa). Fifty-three different infectious agents, all with zoonotic potential, were reported to be carried by commensal rats; 48 by the brown rat ( Rattus norvegicus ) and 20 by the black rat ( R. rattus ). There was a tendency for rural areas to harbour more rat-borne microbes than urban areas regarding the brown rat, but the opposite could be observed for the black rat. The study clearly indicated that an improved surveillance on wild rats is needed in Europe, and further indicated the pathogens and geographical areas where the major focus is required. For example, six zoonotic microbes seemed to be clearly more geographically widespread in Europe than others; virulent or resistant E. coli , pathogenic Leptospira spp., Hymenolepis diminuta, H. nana, Capillaria hepatica and Toxoplasma gondii .

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.

Infection with helminth parasites reduces the severity of concomitant inflammatory disease in adult mice. There is an alarming increase of inflammatory bowel disease (IBD) in children. It is important to determine whether helminth therapy would be of value in pediatric IBD and whether triggering immunological memory to the worm would be anticolitic. Three-week-old (young) and eight-week-old (adult) Balb/c mice were infected with H. diminuta, and infectivity and T helper 2 (Th2) immunity were assessed. Other mice received H. diminuta with or without a crude worm extract ( HdE) 28-42 days postinfection (dpi) with or without dinitrobenzene sulphonic acid [DNBS, 1.5 mg (young) or 3 mg (adults), ir], and colitis was assessed 72 h later. Infected young mice developed Th2 immunity and expelled H. diminuta; expulsion was delayed by ~2 days compared with adult mice. Colitis, as gauged by macroscopic disease and histopathology scores, was less severe in young mice infected 10 days, but not 8 days, before DNBS. Protection against DNBS-induced colitis was accompanied by an increased capacity to make interleukin (IL)-4 and IL-10. Mice infected with H. diminuta were not protected from DNBS-colitis when challenged 28 days later; however, injection of these mice with HdE coincident with DNBS resulted in less disease and increased splenic IL-4 and IL-10. Using a boost (500 μg HdE, 28 dpi) and repeat HdE (100 μg, 42 dpi) regimen with infected mice suppressed DNBS-colitis, as did adoptive transfer of splenic CD4 + T cells from infected mice with low-dose HdE challenge. Should these data translate to IBD, then helminth therapy could be of value in pediatric-onset IBD, and defining the antigen(s) that elicit antihelminth immunological memory could serve as an anticolitic approach in previously infected individuals. NEW & NOTEWORTHY This study demonstrates that juvenile mice are protected from colitis by infection with the tapeworm Hymenolepis diminuta and that using worm antigen to trigger an immunological memory response in previously infected mice can be used to limit the severity of colitis.

Cestodes (tapeworms) have complex adaptations to their obligatory parasitic life-style. Among these adaptations, they show many evolutionary innovations in their development, including complex life-cycles with multiple hosts and life-stages, several independent origins of asexual reproduction, and the evolution of segmentation as a mean to generate massive reproductive output. Therefore, cestodes offer many opportunities for the investigation of the evolutionary origins of developmental novelties (evo-devo). However, cestodes have not been exploited as major models for evo-devo research due to the considerable technical difficulties involved in their study. In this review, a panoramic view is given of classical aspects, methods and hypothesis of cestode development, together with recent advances in phylogenetics, genomics, culture methods, and comparative analysis of cestode gene expression. Together with the availability of powerful models for related free-living flatworms, these developments should encourage the incorporation of these fascinating parasites into the first-line of evo-devo research., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Senna alexandrina Mill. has been used for antimicrobial activity. In the present study, the crude ethanolic extract of the plant and a synthetic compound Sennoside were tested in vitro on Hymenolepis diminuta to evaluate its potential anthelmintic efficacy through ultrastructural changes. Worms were maintained between rat model and beetle and the test parasites were exposed to different concentrations of crude ethanolic leaf extracts of S. alexandrina . Praziquantel was used as a reference drug. Dose dependent efficacy was observed in terms of motility and time of mortality in all treated parasites. Ultrastructural micrography revealed irrevocable destruction all over the body tegument accompanied with sloughing of microtriches and swellings of the basal lamina. Vacuolization of the syncytium along with sparsely cytoplasmic cytons and depletion of parenchymatous layer were observed accompanied by deformities in the cell organelles. Extensive deformities in the tegument indicates that the plant extract alter membrane permeability of the parasite leading to paralysis and subsequent death. Thus, S. alexandrina can be regarded as a potential anthelmintic agent.

Background: Rattus norvegicus (brown rat) and Rattus rattus (black rat) are known carriers of bacteria, viruses, and parasites of zoonotic and veterinary importance. Moreover, rats may play a role in the transmission of muscle larvae of the zoonotic nematode Trichinella spiralis to farm animals. We aimed to study the intestinal and intramuscular helminths in wild rats from three different environments to assess the relevance of rats as carrier of zoonotic parasites for public health., Materials and Methods: Wild brown rats (117 individuals) and black rats (44 individuals) were captured at farms, in suburban and in rural environments in the Netherlands. Intestinal helminths were isolated and identified morphologically. Artificial digestion was used to isolate muscle larvae., Results and Discussion: Morphological analysis of rat intestinal contents yielded six nematode species (Syphacia muris, Heterakis spumosa, Aonchotheca murissylvatici, Trichuris muris, Nippostrongylus brasiliensis, and Strongyloides sp.), three cestode species (Hymenolepis diminuta, H. nana and Hymenolepis (=Rodentolepis) fraterna), and four trematode species (Plagiorchis muris, Plagiorchis proximus, Echinostoma chloropodis, and Notocotylus imbricatus).Black rats at farms displayed the lowest intestinal helminth species variation (six species) and carried overall on average 0.93 species simultaneously. In comparison, brown rats at farms carried seven helminth species and 1.91 species simultaneously. Brown rats from suburban environments displayed the highest species variation (11 species) at 1.82 simultaneous helminth species. Absence of trematodes from rats at farms may suggest limited exchange of rats between farms and surrounding wet rural environments. We report four species of veterinary (Syphacia muris) or zoonotic relevance (Hymenolepis diminuta, Hymenolepis nana and Plagiorchis muris). We did not find Trichinella muscle larvae, consistent with long-term prevalence in Dutch wild rats.

Aim: Review of dwarf tapeworm (Hymenolepis nana) presentations to Northern Territory (NT) Government health-care facilities over 12 years. We postulated H. nana infections would remain unchanged despite the introduction of deworming programmes as H. nana is not eradicated with albendazole treatment., Methods: A retrospective observational analysis of consecutive microbiologically confirmed cases of H. nana identified by NT Government health-care facilities between 2002 and 2013., Results: Four hundred sixty-one episodes of H. nana infection were identified over the 12-year period from 68 387 faecal samples. Infections were overwhelmingly in young children with a median age of patients being 3.0 years (interquartile range 2.25-4.67). Patients were predominantly Indigenous (98.9%, P = 0.001) and infections occurred across the entire NT. Infections were associated with anaemia (18.2%) and eosinophilia (39.6%). The annual prevalence of NT Government health-care facility diagnosed H. nana infection remains relatively constant from 6.9 {4.8-9.0 (confidence interval (CI))} cases per 10 000 Indigenous population in 2002, compared with 6.6 (4.7-8.4 CI) cases per 10 000 Indigenous population in 2013. Infection rates in Indigenous children <5 years of age were: 46.1 (16.4-75.8 CI) cases/10 000 in 2002, compared with 44.3 (15.3-73.3 CI) cases/10 000 Indigenous population in 2013., Conclusion: H. nana is the most frequently identified cestode (tapeworm) in NT Government health-care facilities. H. nana remains endemic throughout the NT, predominantly infecting Indigenous children less than 5 years of age., (© 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).)

The aim of the study was to determine if Ulomoides dermestoides behaves as an intermediate host of Hymenolepis diminuta, therefore one hundred of them were experimentally infected with tapeworm eggs. As a result, it was found that in 92% of the insects formed cysticercoids which, inoculated in laboratory rats, developed the adult stage. These adults produced eggs with which the infection process was repeated, obtaining the same results. Therefore it can be said that U. dermestoides experimentally acts as an intermediate host.

The results of this study show that the oral administration of ivermectin (48 mg/L) repeatedly for 72 h used in accordance with the present protocol is a safe and highly effective treatment for Giardia spp. and Hymenolepis nana in laboratory rat colonies. The drug can be easily and safely administered using drinking water. This simple regimen should control pinworm infection (Syphacia muris), a problem that can be endemic in laboratory colonies. Experiments using healthy animals are likely to generate more consistent results, thereby requiring a reduced number of animals per group., (© The Author(s) 2014.)

Differentiation and development of parasites, including longevity in host animals, are thought to be governed by host-parasite interactions. In this review, several topics on the developmental biology of cestode infections are discussed from immunobiological perspective with a focus on Hymenolepis, Taenia and Echinococcus infections. The basic premise of this review is that 'differentiation and development of cestodes' are somehow affected by host immune responses with an evolutionary history., (© 2014 John Wiley & Sons Ltd.)

The microbiome is now widely recognized as being important in health and disease, and makes up a substantial subset of the biome within the ecosystem of the vertebrate body. At the same time, multicellular, eukaryotic organisms such as helminths are being recognized as an important component of the biome that shaped the evolution of our genes. The absence of these macroscopic organisms during the early development and life of humans in Western culture probably leads to a wide range of human immunological diseases. However, the interaction between the microbiome and macroscopic components of the biome remains poorly characterized. In this study, the microbiome of the cecum in rats colonized for 2 generations with the small intestinal helminth Hymenolepis diminuta was evaluated. The introduction of this benign helminth, which is of considerable therapeutic interest, led to several changes in the cecal microbiome. Most of the changes were within the Firmicutes phylum, involved about 20% of the total bacteria, and generally entailed a shift from Bacilli to Clostridia species in the presence of the helminth. The results point toward ecological relationships between various components of the biome, with the observed shifts in the microbiome suggesting potential mechanisms by which this helminth might exert therapeutic effects.

Specific features in the formation of cestode species composition in the common shrew in different biotopes have been analyzed. Four categories of parasites have been recognized depending on a degree of dominance: dominants (Neoskrjabinolepis singularis, Molluscotaenia crassiscolex), subdominants (Ditestolepis diaphana), adominants A (Staphylocystis furcata, Vigisolepis spinulosa, adominants B (Hymenolepis scutigera, Dilepis undula, D. secunda, Taenia mustelae). A significant similarity was discovered between the species diversity and the dominance characteristics of cestodes. It was found that the distribution of mass species of parasites in the host population corresponds to the gamma distribution model. In regard to cestodes examined, a hypothesis considering the spatial structure and size of territory occupied by stable parasitic system is put forward.

The defensive role of nitric oxide (NO) against Hymenolepis nana was investigated in vivo and in vitro studies. Serum NO levels were increased (P < 0.001) in mice 5 days (cysticercoid stage) and 15 days (adult stage) after H. nana induced oral infection with 1000 eggs/mouse, compared with normal controls. Meanwhile, L-NAME, a NO synthase inhibitor, oral administration in drinking water to infected mice caused a non significant decrease in serum NO levels (P > 0.05) compared with normal controls, and was associated with a significant increase in number of both cysticercoids and adult worms (P < 0.001) compared to that in infected mice 5 and 15 days post infection. In an in vitro study, the NO donor; sodium nitroprusside caused an increased mortality rate of H. nana cysticercoids and adult worms (P < 0.001) compared with controls without NO donor, and this was in a concentration-dependent manner (P < 0.001). Implications of these results are discussed.

A protein of unknown function has been identified as a key serological tool for diagnosis of human tapeworm neurocysticercosis, a major worldwide neurological disease. Our own sequence analysis predicts that this protein is a member of a newly identified cestode specific oligomeric hydrophobic ligand binding protein family. In this report, using a rat cestode model, we confirm that homologues of this protein can bind fatty acids and their derivatives, and thus suggest a biological function for this key diagnostic tool.

Many animals obtain reliable information about potential mates, including whether they are parasitised or not, mostly from olfactory cues in urine. Previous experiments with rodents have shown that females can detect parasites in males that are potentially transmissible during copulation, so that females can directly avoid infection by discriminating against parasitised males. Here, using choice tests, we examine whether female rats can distinguish males infected with the tapeworm Hymenolepis diminuta Rudolphi, 1819, a parasite with a complex life cycle and thus not directly transmissible among rats. Female rats tended to spend more time investigating the urine of non-parasitised males than that of parasitised males. The magnitude of the parasite burden in the infected males had no effect on the females' preference for the non-parasitised males. We also found that parasitised males had lover testosterone levels in their blood than non-parasitised males. These results suggest that females use cues in male urine reflecting either the presence of the parasite and/or lower testosterone levels to avoid parasitised males and possibly secure resistance genes for their offspring.

When provided with fecal pellets from uninfected (control) rats and rats infected with the tapeworm Hymenolepis diminuta, more fed and starved (72 h) female and starved male Tenebrio molitor fed on fecal pellets from infected- than from control rats; compared to fecal pellets from controls rats, fed males avoided the infective fecal pellets. Uninfective and infective fecal pellets had similar moisture contents, so increased coprophagic activity was not due to differences in moisture content. Fed and starved males and females were fed on fecal pellets containing tapeworm eggs and examined for cysticercoids. Significantly greater numbers of starved beetles than fed beetles were infected with cysticercoids, but the numbers of infected males and females within each treatment were not significantly different. On the other hand, males contained significantly greater numbers of cysticercoids than did females, and there was no significant difference between the numbers of cysticercoids recovered from fed and starved beetles. The data support the hypothesis that the feeding behavior of T. molitor on rat feces is altered by the presence of tapeworm eggs. The data demonstrated further that transmission dynamics are affected by a complex interaction of the beetle's sex and nutritional status.

We have previously reported that Ca2+ influx into the mitochondria of Hymenolepis diminuta, a rat intestinal cestode, takes place through an electrophoretic uniport system. Sodium and lithium were found to induce efflux of 45Ca2+ from the mitochondria of H. diminuta. The two cations induced the efflux in a hyperbolic and linear fashion, respectively. The efflux as well as an exchange of external Ca2+ with internal 45Ca2+ was inhibited by lanthanum. The type of Ca2+ transport system in the cestode organelle has been discussed and compared with that of the host (mammalian) counterpart.

In vivo phosphorus-31 nuclear magnetic resonance (31P NMR) spectra and those of extracts of Tenebrio molitor L. infected with metacestodes of Hymenolepis diminuta R. showed modifications in the amounts of phosphorous-containing metabolites when compared with those of uninfected beetles. Infected females were more affected than infected males, having significantly more glucose-6-phosphate (Glu-6-P), glycerol-3-phosphate (Gly-3-P), and phosphorylethanolamine (PE), but less inorganic orthophosphate (Pi), glycerophosphorylethanolamine (GPE), gylcerolphosphorylcholine (GPC), phosphoarginine (PAr), and adenosine diphosphate (ADP). Infected males had more Glu-6-P and PE, but less Pi, GPE, and GPC. These changes directly reflected the phosphorylation potential of infected hosts, which increased approximately 100% and 50% in infected females and males, respectively.

Isoxazole derivatives have been shown to possess antiparasitic activity. In the present study, 3-substituted 5-methylthio-isoxazoles were synthesized and tested for anthelmintic activity, along with some other isoxazoles which have been reported but not tested earlier. Nine compounds (2a, 2b, 2e, 2g, 2u, 3a, 3b, 3e and 3f) showed activity against both A. ceylanicum and N. dubius in vitro. Twelve compounds (2a, 2b, 2d, 2e, 2f, 2h, 2l, 2n, 2o, 2u, 3d and 3e) showed activity against N. dubius in vivo, a parasite of veterinary importance.

1H NMR spectra of the duodenum, jejunum and ileum tissues of the small intestine of a rat showed metabolic gradients. 2. The concentrations of metabolites in these gut regions were altered by the presence of the tapeworm Hymenolepis diminuta. 3. In the infected duodenum there was significantly less glycogen, glucose and phosphocreatine/creatine, but significantly more lactate than in the corresponding controls. 4. Infected jejunum contained significantly less betaine but significantly more succinate, alanine and lactate. 5. Infected ileum had significantly less glycogen and taurine but significantly more alanine and lactate.

Ground feed containing 0.33% active niclosamide fed ad libitum to hamsters for a period of 7 da eliminated Hymenolepis nana from all animals tested. Six- to 8-wk-old hamsters fed at 3 and 10 times the therapeutic dose were not adversely affected.

The evaluated helminth carrier rate among foreign workers give rise to many problems under socio-economic, hygienic and occupational aspects. The evaluation of helminth infestation is connected with considerable uncertainty. Based on the author's examinations these problems are critically investigated from the point of view of both, the employer and the employee. It is shown in tables that in the Institute of Hygiene and Microbiology of Würzburg during 1973/1974 497/702 respectively faecal examinations were performed among German and foreign employees and workers. No difference was noted in the overall positive rates in both groups. But there were distinct differences in the species of helminths noted: Among the foreign workers mainly Trichuris trichiura, Ascaris lumbricoides and Enterobius vermicularis were noted while among Germans Taenia saginata prevailed. Noteworthy is the fact, that workers from Turkey and Yugoslavia have occasionally three and more species of helminths and pathogenic protozoa in a single specimen. Since the helminth species found are not transmitted from man to man and since usually the circumstances do not permit a transmission via food, such carriers of helminth don't represent a direct danger for man or the contamination of foofdstuff. For hygienic reasons however helminth carriers may not be acceptable in certain occupations. In case of clinical symptoms the treatment of such patients is required for medical reasons. In spite of frequent absence of clinical signs the consequent liberation of the carriers from their intestinal worms and the sanitation of their personal environment should not be neglected.

Of 8 fecal specimens from the antelope rat, Tatera indica Hardwicke examined, 4 were found positive for intestinal parasites. Among these was Eimeria taterae sp. n., sporulated oocysts of which are described, their characteristics serving for the diagnosis of this species. Entamoeba coli cysts, as well as ova of Hymenolepis sp. and Trichuris sp., were also found.

Evidence of helminthic intestinal parasites was found in 97,0% of stools of 544 Xhosa schoolchildren living in Cape Town. The commonest parasite was Trichuris trichiura, which infested 89,9% of the children. In contrast, only 9,8% of 387 Xhosa children living in the Tsolo district, Transkei, had evidence of intestinal parasites in their stools, Hymenolepis nana being the commonest. In spite of the unsatisfactory sanitary conditions in the Tsolo area compared with those in Guguletu, Cape Town, where all sewage is waterborne, few rural children were infested. The high prevalence of infestation in the Guguletu children suggests extensive contamination of the soil in the area by parasitic ova. In view of the magnitude of the extent of parasitic infestation in the Guguletu children, a vigorous and sustained programme of medication and education will have to be undertaken if the problem is to be resolved.

Forty-two Tunisian patients suffering from Hymenolepis nana infection, were treated with 500 mg tablets of mebendazole, 3 times a day, 3 consecutive days for 5 patients (group I) and 4 consecutive days for 37 patients (group II). The faeces were examined during the third and fifth week, after treatment. 18 (42.8%) patients, 2 from group I and 16 from group II, were cured. The tolerance of the product was excellent and there were no adverse side-effects.

Liver weight of mice was significantly influenced, in order of decreasing prominence, by environmental temperature, infection with Hymenolepis microstoma and sex. Livers of infected and uninfected mice (both sexes) maintained at 5 C for 20 days were proportionally larger (alpha less than or equal to 0.05) than those from corresponding groups of mice kept at 35 C and, except for uninfected males, at 21 C. regardless of temperature, H. microstoma (single-worm infections) produced significant (alpha less than or equal to 0.05) hepatomegaly in all groups of female mice, but, in males, this occurred only in mice maintained at 5 C. At 21 C male mice had proportionally larger livers (alpha less than or equal to 0.05) than corresponding groups of females, but this sexual difference disappeared when mice were maintained at 5 or 35 C. Temperature and sex had a slight but significant effect on bile duct weight. Infection, on the other hand, produced a marked increase in the weight of this organ in both sexes at 5, 21 and 35 C.

4-Isothiocyanato-4'-nitrodiphenylamine possessed anthelmintic activity against Nippostrongylus dubius and Hymenolepis nana in mice and H. diminuta in rats as determined by both egg counts and recovery of parasites at autopsy. No activity was detected against the cestode. Spirometra mansonoides, in cats.

A reported practice of live beetle ingestion in Southeast Asia was investigated among urban Chinese in Kuala Lumpur, Malaysia. Results of four casefindings are: (1) this practice may not be confined to West Malaysia, (2) it occurs among Chinese and Malays, (3) the original use of the beetles as an aphrodisiac has been modified to include treatment of a wide variety of ailments and diseases and (4) the practice is relatively uncommon among urban Chinese. It was also found through experimental studies that ingestion of the live beetles (Palembus dermestoides) represented a potential public health hazard in that the beetles were able to serve as a host for the human-infecting tapeworm Hymenolepis diminuta (Sullivan et al., 1977).

An electron microscopic study of the larval stages of two Cyclophyllid Cestodes, Anomotaenia constricta and Hymenolepis stylosa shows the presence of a morphogenetic field whose center is located in the scolex. This field stimulates the graduated differentiation of the tegument and associated structures from the scolex to the cercomer.