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A previously unrecognized species of hymenolepidid cestode attributable to Hymenolepis is described based on specimens in Peromyscus polionotus, oldfield mouse, from Georgia near the southeastern coast of continental North America. Specimens of Hymenolepis folkertsi n. sp. differ from those attributed to most other species in the genus by having testes arranged in a triangle and a scolex with a prominent rostrum-like protrusion. The newly recognized species is further distinguished by the relative position and length of the cirrus sac, shape of seminal receptacle, and relative size of external seminal vesicle and seminal receptacle. Hymenolepidid cestodes have sporadically been reported among the highly diverse assemblage of Peromyscus which includes 56 distinct species in the Nearctic. Although the host genus has a great temporal duration and is endemic to the Nearctic, current evidence suggests that tapeworm faunal diversity reflects relatively recent assembly through bouts of host switching among other cricetid, murid, and geomyid rodents in sympatry.

Enteroparasites in children from three marginal urban districts of Trujillo (Peru) were studied to treat these children and to design a prevention and control programme. A total of 845 children were examined. The general prevalence of enteroparasites was of 66.3%, and 45.6% were multiparasitized. The pathogenic enteroparasite prevalence were 23.8% (Giardia lamblia), 4.6% (Iodamoeba buschlii), 2.6% (Cyclospora cayetanensis), 2.2% (Hymenolepis nana), and 2% (Cryptosporidium spp.). G. lamblia was the most frequent parasite both in diarrheic children (28.1%) as well as in nondiarrheic ones (19.5%). The G. lamblia genotypes were molecularly characterized by sequence analysis of the glutamate dehydrogenase (gdh) gene using PCR and RFLP. Sequence analysis revealed both Assemblage A (AI and AII) and Assemblage B (BIV), with the predominance of Assemblage AI. All the samples with Assemblage A were diarrheic but not those with Assemblage B. This is the first study of molecular characterization of G. lamblia in Peruvian children and confirms the importance of asymptomatic patients in the transmission of the giardiosis, especially in places with poor hygiene and sanitation.

The successful maintenance of Hymenolepis pseudodiminuta, isolated from Apodemus speciosus, is described for the first time. In the laboratory, the flour beetle, Tribolium confusum, and F344 rats could serve as intermediate and definitive hosts, respectively. In single worm infections with H. pseudodiminuta, which were carried in two groups of rats, adult worms were recovered from eight and seven out of ten rats, respectively, while Hymenolepis diminuta was found in all of ten rats 6 weeks after inoculation. The worm weight of H. pseudodiminuta in rats was significantly lower than that of H. diminuta. The egg output of H. pseudodiminuta occurred significantly earlier than that of H. diminuta. The number of eggs in the faeces of H. diminuta-infected rats was approximately twofold higher than the number in the faeces of H. pseudodiminuta-infected rats throughout the course of the infection. Mucosal mast cells in rats infected with H. pseudodiminuta were significantly more common than in rats infected with H. diminuta. No detectable IgE antibodies were found in the uninfected and H. diminuta-infected rat groups; however total IgE was detected in H. pseudodiminuta-infected rats but the concentrations were variable between individuals.

The two related species, Rodentolepis straminea (Goeze, 1782) and Rodentolepis microstoma (Dujardin, 1845) (Cestoda, Hymenolepididae), both parasites of rodents, were compared morphologically and electrophoretically. Adult worms were isolated from three wild rodent species of the family Muridae (Apodemus flavicollis, Apodemus sylvaticus, and Mus musculus) from three different sites in Spain and France. Although these two species were strikingly similar in morphological appearance, some of the morphological and metrical features analysed (scolex, mature segments and eggs) can be used for differentiation. Fixed allelic differences were found. Of the ten enzymes detected by starch-gel electrophoresis, six (AAT, AK, GPI, MDH, NP, PGM) showed characteristic isoenzyme profiles in each species. Only in MPI, PEPC, PEPD, and ME enzyme loci were no differences found. The study revealed that the two taxa can be clearly differentiated.

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.

Histochemically demonstrable activity of a serine proteinase was detected in the penetration glands of Hymenolepis diminuta hexacanths. At the optimal pH of 8.4 the enzyme hydrolyzed Af-blocked L-aminoacyl- and N-blocked L-peptidyl-naphthylamides bearing L-arginine at the P1 subsite. The proteinase did not require either Ca2+ or Mg2+ for its activity and was insensitive to 1 mM EGTA and 1 mM EDTA. Organic fluorophosphates inhibited it, whereas thiol-blocking compounds did not. At operative pH values of 4.8 and 3.8 generated during electrophoresis in a stacking and a resolving gel, respectively, the proteinase migrated toward the cathode. When examined for proteolytic activity at the optimal pH of 8.4, the separated enzyme produced a single band of gelatinolysis in a gelatin-containing polyacrylamide gel. During in vitro maintenance of the hexacanths, the secretion from their penetration glands formed a mucous cyst surrounding the individual larvae. The cyst was resistant to and protected the hexacanths from the proteolytic activity of trypsin, papain, and proteinases extracted from the gut of the beetle Tenebrio molitor (the host). Hexacanths extracted from the hemocoel of T. molitor at 24 and 48 h after infection were surrounded by similar mucous cysts. Consequently, roles in penetration and protection for the secretion from the penetration glands are postulated.

The localization of FMRFamide-related peptide (FaRP) immunoreactivity was determined during different stages of development of the rat tapeworm Hymenolepis diminuta. In the adult worm (14 days old), FaRP immunostaining was most intense in the scolex and concentrated in the central nervous system (cerebral ganglia and transverse commissures) and around the lips of the suckers. In the strobila, medial and lateral longitudinal nerve cords (LNCs) and ladder-like connecting commissures were the only tissue stained. Immunoreactivity in the medial LNCs of the adult tapeworms extended only to and included proglottides containing developing testis and seminal receptacle but disappeared in proglottides in which primordial ovaries were first detected. Radioimmunoassay confirmed that FaRPs were concentrated in the scolex/neck region of the adult worm (3.9 +/- 1.5 pmol mg protein-1), whereas the lowest concentrations (0.2 +/- 0.19 pmol mg protein-1) were recovered from the regions of the strobila containing shelled eggs. The pattern of FaRP immunoreactivity observed in 5- and 7-day-old worms was similar to that seen in adult worms, but in 2- and 3-day-old worms the pattern of immunoreactivity observed in the cerebral ganglia, transverse commissures, and LNCs differed significantly as compared with that seen in older worms. These results indicate differential utilization and/or roles for FaRPs during development and suggest both central and sensory roles in this tapeworm.

Hymenolepis nana is the most common cestode parasitizing humans, yet it is under-diagnosed. We determined the optimal flotation solution (FS) for the diagnosis of this intestinal parasite with the FLOTAC method, and compared its diagnostic accuracy with an ether-concentration technique and the Kato-Katz method. Zinc sulphate (specific gravity 1.20) proved to be the best-performing FS. Using this FS, we detected 65 H. nana infections among 234 fixed fecal samples from Tajik and Sahrawi children (prevalence 27.8 %). The ether-concentration technique detected 40 infections (prevalence 17.1 %) in the same samples. Considering the combined results as a reference, the sensitivities of FLOTAC and ether-concentration were 95.6 % and 58.8 %, respectively. The Kato-Katz method resulted in a prevalence of only 8.7 %. In terms of eggs per gram of stool, a significantly (P

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.

We studied the pattern of cGMP immunostaining (IS) after stimulation with a nitric oxide donor in the presence of an inhibitor of phosphodiesterase in adult Hymenolepis diminuta. cGMP-IS was detected in the peripheral nervous system, especially in nerve fibres close to the body muscle fibres. cGMP-IS also occurred in terminals beneath the basal lamina of the tegument and between the muscle fibres of the suckers. The pattern of cGMP-IS was compared to that of 5-HT-IS and GYIRFamide-IS. TRITC-conjugated phalloidin was used to stain the musculature.

Cysticercoids as well as 6-, 10-, and 14-day Hymenolepis diminuta were evaluated in terms of enzymatic activities related to phosphoenolpyruvate (PEP) utilization and mitochondrial succinate accumulation. The data obtained support a transition toward anaerobic electron-transport-dependent succinate accumulation, characteristic of adult H. diminuta, with development from cysticercoid to adult. This transition was reflected most prominently in the increasing activities of PEP carboxykinase (PEPCK), malate dehydrogenase, NADPH → NAD+ transhydrogenase, and fumarate reductase. Developmental increases in PEPCK/pyruvate kinase (PK), fumarate reductase (FR)/NADH oxidase (NO), and FR/succinate dehydrogenase (SDH) activity ratios were also apparent. Evaluations of “egg-free” immature, mature, and pregravid-gravid segments of adult H. diminuta revealed that in general the greater levels of activity were associated with the immature and mature segments. Whereas FR/NO and FR/SDH ratios remained relatively constant in segment comparisons, the greatest PEPCK/PK ratio was associated with the pregravid-gravid segment.

The vitellocytes of Hymenolepis microstoma contain protein globules as building material for the shell of egg cocoons. Complex carbohydrates were detected as an additive component, dispersed in the matrix of the shell globules. Similar glycans were found at newly formed shells, suggesting that these molecules are provided by the vitellocytes. The glycans remained associated with the surface of mature eggs. Carbohydrate residues, characterized using gold-labeled lectins, were N-acetylglucosamine, galactose, or the N-acetyllactosamine sequence of these residues and N-acetylgalactosamine, whereas glucose, mannose, and fucose were not demonstrable. The glycans scarcely stained with periodic acid-Schiff and, thus, seem to have few diols, and they did not bind cationic dye, indicating that they are not glycosaminoglycans. Since they occur in significant amounts, the glycans may have fundamental, as yet undetermined function(s) in the formation of the shells and/or interactions of the cocoons with the host.

The release of preloaded [3H]-L-glutamate by tissue slices of Hymenolepis diminuta was examined by the technique of electrical field stimulation. For tissues slices in balanced saline, a high-field strength of 1.78 A resulted in a highly elevated increase in the rate of release of radiolabel, which was suppressed in calcium-free saline. This technique may prove useful for screening helminth tissues for potential neurotransmitters.

Dimethyl sulfoxide (DMSO), commonly used for cryoprotection or for the solvation of cytoskeleton-modifying drugs, causes changes in the topology of the plasma membrane of the tegumental brush border in the tapewormHymenolepis diminuta; however, relatively long exposures or high concentrations are required. In tapeworms treated with DMSO concentrations of ≥1% in the present study, the interaction of the tegumental surface membrane with the underlying cytoskeleton may have been disrupted at focal points in the brush border, resulting in a partial loss of the membrane anchoring required for the structural integrity of the brush border. Blebbing of the tegumental surface was prominent only after exposure to 1% DMSO for 20 h in vitro culture with RPMI 1640, and vesiculation of the membrane along the microvillar (microtriche) shafts, which may have been related to the in vitro conditions, was amplified by the presence of concentrations of ≥1% DMSO in the incubation medium. The tegumental response to DMSO was not uniform but regional, consistently appearing to be more prevalent on the distal aspects of each proglottid rather than on the edge proximal to the scolex. Blebbing and vesiculation were not seen on the basal aspect of the tegument, including the basal ectocytoplasmic plasma membrane, the perikarya, and the internuncial processes. Microvillar core bundles of actin microfilaments persisted following 8 h in vitro exposure to all three concentrations of DMSO tested (0.1%, 1%, 5%); however, only in tapeworms that were treated in vitro with 5% DMSO for ≥ 8 h did core microfilament bundles appear to lose the rigidly straight and parallel organization characteristic of control tapeworms that were incubated either in the absence of DMSO or with 0.1% DMSO. Other components of the brush border cytoskeleton (i.e., microvillar caps, junctional tubules, and tunics) appeared unaffected by DMSO except at foci where blebbing occurred. These data suggest that in vitro concentrations of

The outer part of Hymenolepis diminuta tegument was extracted with 3 M KCl. The antigen was adsorbed from the extract on an affinity column containing H. diminuta-infected rat immunoglobulin immobilized on Sepharose 4B and could be eluted with 2.5 M urea at pH 2.8. Analysis of polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of both the crude extract and material eluted from the column showed that the latter was markedly purified. Double diffusion and immunoelectrophoresis revealed 11 and 4 antigenic components in the crude extract and purified preparation, respectively.

The localisation and distribution of 5-hydroxytryptamine (5-HT, or serotonin) and a number of vertebrate neuropeptides in the nervous system of excysted (0-24 h) cysticercoid larvae of Hymenolepis diminuta were determined by an indirect immunofluorescence technique in whole-mount preparations. In the central nervous system, cell bodies and nerve fibres immunoreactive to 5-HT are present in the main commissure, lateral and rostellar ganglia, and the longitudinal nerve cords and their connectives. In the peripheral nervous system, immunoreactive nerve fibres occur in a poorly developed nerve plexus within each sucker. Among the vertebrate peptides tested, antisera to pancreatic polypeptide (PP), polypeptide YY (PYY), peptide histidine isoleucine (PHI) and gastrin-releasing peptide (GRP) gave positive results. Immunoreactivity to PP and PYY paralleled that of 5-HT, with greater numbers of cell bodies present in the different locations within the scolex nervous system, and the sucker plexus being more prominent. The number of PP-reactive cells in the lateral ganglia and main lateral, longitudinal nerve cords increased over the 24-h period in culture. Results with antisera of different specificities to PP and PYY suggest that the immunoreactivity may be due to a peptide with closer structural affinity to PYY than to PP. Immunoreactivity to PHI is restricted to the main lateral nerve cords in the body of 0-h worms, extending into the median nerve cords by 12 h and 24 h. Immunoreactivity to GRP became evident after 12 h in culture and was confined to the longitudinal nerve cords, in particular the median nerve cords. The results are discussed in relation to the proposed transmitter and regulatory roles of 5-hydroxytryptamine and the neuropeptides.

Glutamate-like immunoreactivity in the cestode Hymenolepis diminuta was studied at the light microscopic level using an antibody specifically directed against a reduced conjugate of glutamate linked to protein by glutaraldehyde. Relatively low levels of glutamate-like immunoreactivity were present in the subtegumental region, which was presumed to reflect an active metabolic pool. Relatively high levels of this reactivity were observed in the longitudinal nerve cords and associated cells, and somewhat lower levels were occasionally noted in ring commissures. The present data in conjunction with previous studies on glutamate in H. diminuta, support the hypothesis that glutamate is an excitatory neurotransmitter in the platyhelminths.

Synoptic data and an understanding of helminth parasite diversity among diverse rodent assemblages across temperate latitudes of North America remain remarkably incomplete. Renewed attention to comprehensive survey and inventory to establish the structure of biodiverse faunas is essential in providing indicators and proxies for identifying the outcomes of accelerating change linked to climate warming and anthropogenic forcing. Subsequent to the description of Hymenolepis folkertsi in the oldfield mouse, Peromyscus polionotus, additional specimens of hymenolepidids were collected or discovered in archived museum repositories from multiple species of deer mice (Peromyscus maniculatus, Peromyscus leucopus), the golden mouse (Ochrotomys nuttalli), chipmunks (Tamias striatus, Tamias amoenus), the 13-lined ground squirrel (Ictidomys tridecemlineatus), and tree squirrels (Sciurus carolinensis, Sciurus niger) from disjunct localities in the USA spanning southern Georgia, Virginia, Pennsylvania, Connecticut, the Upper Peninsula of Michigan, Wisconsin, and central Idaho. Specimens were largely consistent morphologically with the original description of H. folkertsi. Initial DNA sequence data, from a portion of the mitochondrial NADH dehydrogenase subunit 1, demonstrated intraspecific variation among three apparently geographically isolated populations attributed to H. folkertsi (uncorrected genetic distances of 2.7 % (Idaho and Michigan), 2.4 % (Virginia + Pennsylvania and Michigan), and 1.89 % (VA + PA and ID). Geography rather than host association explains the distribution and occurrence of H. folkertsi, and host colonization among deer mice, chipmunks, and other sciurids within regional sites is indicated. Genetic divergence revealed across localities for H. folkertsi suggests historically isolated populations, consistent with extended evolutionary and biogeographic trajectories among hymenolepidids and species of Peromyscus and Tamias in North America. Field inventory, that revealed these parasite populations, substantially alters our understanding of the distribution of diversity and provides insights about the nature of the complex relationships that serve to determine cestode faunas in rodents.

A capture enzyme-linked immunosorbent assay (ELISA) for the detection of Hymenolepis diminuta coproantigen in detergent-solubilised faecal supernatants was developed. The assay was sensitive to 400 ng H. diminuta protein/ml faecal supernatant and to 30 ng/ml in PBS 0.3% Tween. Faecal antigen levels started to rise on day 7 post infection and peaked on day 20. Following drug treatment of infected rats with 10 mg/kg praziquantel, there was an initial steep rise in faecal antigen levels, followed by a decline to background levels for uninfected animals by day 7 post treatment. When assayed against faecal supernatants prepared from H. microstoma, H. citelli, Diphyllobothrium ditrenum, Necator americanus, Strongyloides ratti and Nematospiroides dubius infections as well as uninfected animals, all results from these groups were 2 SD below those for animals infected with H. diminuta. The application of such a test to important intestinal cestodiases in man is discussed.

Gold labelled lectins were used for electron microscopic localization of carbohydrate components of the tegument surface of two tapeworm species, Hymenolepis nana and H. microstoma. WGA, succinylated WGA, SBA, APA, PNA and, to a lesser extent, Con A were preferentially bound to the spines of the microtrichs. UEA-I and DBA were not adsorbed. The results indicate that the surface coat of both species has exposed N-acetylglucosamine, galactose and perhaps glucose and/or mannose residues. The location of lectin-binding glycoconjugates within the tegument and parenchyma was found using the light microscope on sections of material embedded in Lowikryl K4M after lectin-gold labelling and silver enhancement of the gold grains. The tegument selectively adsorbs WGA and SBA and strongly; adsorbtion of PNA and Con A is less intense. Strong adsorbtion of DBA and PNA was confined to the basal lamina. The parenchyma adsorbed Con A, PNA and DBA, but little WGA and SBA. The results indicate that many glycoconjugates are present in the tegument. They have similar terminal sugar residues to those of the surface coat. The significance of these carbohydrates for host-parasite interactions is discussed.

The carbohydrates on the surface of Hymenolepis diminuta were analyzed with gold-labelled lectins, and it was found that the surface coat of the anterior body differs from that of the strobila in its lectin-binding properties. Binding sites for lectins from Abrus precatorius (APA), Arachis hypogaea (PNA), Glycine max (SBA) and for wheat germ agglutinin (WGA) and succinylated WGA were located on the scolex and strobilation zone. Lectin-gold particles attached mainly to the electron-dense spines. The surface coat may therefore expose sugar residues of the N-acetylglucosamine and galactose types. In contrast, the strobila had few binding sites for the above-mentioned lectins but bound concanavalin A (ConA). Lectins from Dolichos biflorus (DBA) and Ulex europaeus (UEA-I) were not bound to H. diminuta. In juvenile worms from rats, the extension of the WGA- and SBA-positive region of the strobilation zone increased in length with the development of the worms. Lectin binding in juveniles from mice was similar when the mice had been immunosuppressed with cortisone. After the onset of the immune defense against H. diminuta in nontreated mice, a moderate expression of lectin-binding substance also occurred on the strobila. Destrobilated worms were entirely covered with the N-acetylglucosamine- and galactose-containing glycoconjugates, and it is suggested that these worm remnants correspond to the lectin-binding part of normal, growing juveniles. The presence of the carbohydrates is discussed with respect to the relative resistance of the scolex-strobilation zone of H. diminuta to immune rejection.