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At least 127 records · Page 7Linked to original sources
PubMed1978

The Styx Field Trial: effect of treatment of the definitive host for tapeworms on larval forms in the intermediate host.

A 13-year assessment has been made of the effectiveness of a monthly drug treatment programme for the control of tapeworms in dogs in order to prevent hydatidosis (Echinococcus granulosus) and cysticercosis (Taenia hydatigena and T. ovis) in sheep. The age-specific prevalence of T. hydatigena in lambs was used as the principal indicator. The trial was carried out in the Styx Valley of the Maniototo Plain in the South Island of New Zealand.Over an 8-year period dogs were treated monthly with bunamidine hydrochloride at about 25 mg/kg with little effect on the prevalence of T. hydatigena in lambs. The addition of niclosamide at 50 mg/kg for 1 year also had little effect. Eggs appeared to survive from one season to the next. Those shed prior to the lamb-rearing season gave rise to endemic-type patterns; whereas patent infections occurring during this period rapidly gave rise to an epidemic-type pattern or a "cysticercosis storm". In this 9-year period there were 16 "cysticercosis storms" and all susceptible lambs were infected. These storms did not necessarily give rise to a similar prevalence on neighbouring farms, but may have contributed to the overall infective pattern. A similar situation occurred in the first year that nitroscanate at 100 mg/kg was introduced. During this 10-year period, arecoline surveillance of the dog population was undertaken in the remainder of the county and many dogs were found to harbour tapeworms. Both resident and introduced dogs may have contributed to the infective patterns in the Styx Valley.Treatment with nitroscanate was continued monthly in the Styx Valley and niclosamide was used in the remainder of the County for a further 3 years. There was a marked reduction in the age-specific prevalence and lambs on many farms were free from T. hydatigena at slaughter. However, one "breakdown" occurred and this was almost certainly autochthonous.Comparisons with an earlier period when arecoline surveillance was used in the Styx Valley, indicate that the present evidence favours a drug-orientated treatment programme of the definitive host for the control of cysticercosis. However, "breakdowns" caused by either autochthonous or itinerant sources have profound effects, since they involve all susceptible age-cohorts including those that have never been infected and those that have lost the immunity induced by an earlier infection.

Amidines↗
PubMed1987

Distribution of ligulid tapeworms in China.

A survey of ligulid tapeworms carried out from 1979 through 1985 covered 29 provinces and autonomous regions in China. Of the 25,800 fishes of 219 species that were dissected, fishes of 43 species were found to serve as second intermediate hosts. These tapeworms inflict heavy losses on freshwater commercial fisheries. Their distribution indicates 3 distinct major zones: the Qing Zang Gaoyuan is dominated by Ligula; the rest of China, with the exception of a crescent area in Guangdong Province bordering part of the southern coast down to Hainan Island, is dominated by Digramma; and a saddle-shaped corridor, north of 42 degrees N latitude, is characterized by a mix of both genera. Schizothoracinae are the primary hosts for Ligula, of which only Gymnocypris przewalskii przewalskii (Kessler) has economic value. Digramma is predominant in Carassius auratus auratus L. in reservoirs and lakes of 3 main water systems, Heilongjiang, Huang He (the Yellow River), and Chang Jiang (the Yangtze River), and in cultured cyprinids along the lower section of Huang He as well as in bodies of water on the Loess Plateau. Generic validity of ligulids and host specificity, their infection and periodicity, and control methods are discussed.

Animals↗
PubMed1983

Efficacy of fenbendazole against tapeworms in calves.

Forty-five commercial-grade Angus calves naturally infected with tapeworms (Moniezia sp) were used in 2 controlled experiments to evaluate the cestocidal efficacy of 3 dosage levels of fenbendazole, methyl-5-(phenylthio) -2-benzimidazolecarbamate. In the 1st trial, 15 calves were divided into 3 groups of 5 each. One group served as nonmedicated controls. Other groups were drenched with fenbendazole at dosage rates of 10 and 15 mg/kg of body weight. Thirty calves used in the 2nd experiment were divided into 3 equal groups. One group served as nonmedicated controls and the other 2 groups were drenched at dosage rates of 7.5 and 10 mg/kg. Calves were necropsied 13 days after treatment. Doses of 10 and 15 mg/kg were 100% efficacious in reducing the number of tapeworm scolices, and a dose of 7.5 mg/kg was 91.7% effective. Signs of toxicosis were not observed in medicated cattle from time of treatment to necropsy.

Animals↗
PubMed1995

Attachment site specificity and the tapeworm assemblage in the spiral intestine of the blue shark (Prionace glauca).

The parasite assemblage in the scroll-type spiral intestine of 24 specimens of the blue shark Prionace glauca collected off of Montauk, Long Island, New York was investigated. When opened with a longitudinal incision to the right of the ventral blood vessels, the internal mucosal spiral of the spiral intestine of the blue shark could be unrolled into a flat sheet of double-sided mucosal tissue. Attachment sites and parasite assemblages were studied on both sides of the sheet in 12 sharks and on either the inside or the outside of the sheet in 12 additional sharks. Assemblages within host individuals were composed of up to 4 species of tetraphyllidean cestodes including the onchobothriid Platybothrium auriculatum, and the phyllobothriids, Prosobothrium armigerum. Paraorygmatobothrium prionacis, and Anthobothrium laciniatum. Each individual shark hosted 1-4 tapeworm species (mean = 3.7 +/- 0.65). The 12 sharks in which both sides of the mucosal scroll were examined hosted 156-2,382 (mean = 929.1 +/- 818) individual tapeworms. The assemblage consisted of 4 core species. Sharks were not found to host all of the possible combinations of species in their assemblages; the most common combination (17 out of 24 individuals) was the occurrence of all 4 parasite species. A chi-square test revealed no evidence that the 4 species did not occur independently. Regression revealed a significant relationship between shark total length and spiral intestine area. Analysis of covariance (ANCOVA) revealed a significant difference between the surface areas of the 2 sides of the mucosal sheet when shark total length was taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

A comparison of mode of attachment and histopathogenicity of four tapeworm species representing two orders infecting the spiral intestine of the nurse shark, Ginglymostoma cirratum.

This study was undertaken to compare 2 species of Tetraphyllidea and 2 species of Trypanorhyncha with regard to the relationship between attachment structure morphology, mode of attachment, and tapeworm size, to damage at the sites of attachment in the Atlantic nurse shark, Ginglymostoma cirratum. Regions of the spiral intestine with worms attached were removed from 8 nurse sharks and sectioned according to conventional techniques. Sections of 5-50 specimens of each tapeworm species were examined. Regions of the spiral intestine devoid of worms were processed for characterization of the normal mucosa. The normal mucosa was found to consist of a folded surface covered with round-to-oval primary mucosal crypts. In the first 7 or 8 chambers of the spiral intestine the mucosal surface was thrown into secondary folds, forming ridges and secondary crypts. The primary mucosal crypts were lined with a single layer of columnar epithelium resting on a basement membrane. A highly cellular lamina propria and submucosa were found between the crypts and the muscularis mucosa. The small tetraphyllidean Pedibothrium brevispine was found with its scolex lying within the primary mucosal crypts with its hooks embedded in the basement membrane. Epithelial denudation was evident. The large tetraphyllidean Pedibothrium globicephalum was found with its bothridia engulfing large portions of the mucosa and its hooks embedded into the lamina propria. It was associated with moderate to severe mucosal necrosis. The small trypanorhynch Prochristianella tenuispine was found lying between the mucosal ridges in the secondary crypts with its tentacles either penetrating the epithelium, or occasionally, the lamina propria.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1997

Tapeworms morphological changeability in the chain of Hymenolepis diminuta WMS "strain" generations.

The investigations covered 54 subsequent generations of Hymenolepis diminuta WMS "strain" obtained through the administration of 6 cysticercoids of tapeworm to Wistar strain rats and WAG alb. rats. The number of tapeworms at 2.5 months after the infection of rats ranged from 3 to 6, on the average 5.2. Taking into consideration the most important type 1p2a (one testis on the poral side and two testes on the aporal side), 0p3a, 1p3a and 2p1a proglottids a significant differences was found in the distribution of the numerousity of type 1p3a proglottids (P < 0.05). This indicates a possibility of an unguided change of the number of proglottids of this type in a period covering 54 subsequent H. diminuta generations bred in laboratory conditions.

Animals↗
PubMed1999

Genotyping Taenia tapeworms by single-strand conformation polymorphism of mitochondrial DNA.

To overcome limitations in identifying tapeworms of the genus Taenia by traditional approaches, we have established a single-strand conformation polymorphism (SSCP) method utilizing two different regions of mitochondrial (mt) DNA as targets. The NADH dehydrogenase 1 and the cytochrome c oxidase subunit I genes were amplified from genomic DNA by polymerase chain reaction (PCR), denatured and subjected to electrophoresis in mutation detection enhancement gels. SSCP analysis achieved delineation among eight different species of Taenia from different hosts based on characteristic profiles and enabled the detection of intraspecific variability in profiles for some taxa. This SSCP-based typing method has important implications for taxonomy, diagnosis and for studying the genetic structure of Taenia populations.

Animals↗
PubMed1989

Cytoskeletal features of the syncytial epidermis of the tapeworm Hymenolepis diminuta.

A hallmark feature of parasitic platyhelminths is a cytoarchitecturally unusual syncytial epidermis composed of a peripheral layer of continuous cytoplasm (the ectocytoplasm) connected to underlying nucleated cell bodies by small cytoplasmic bridges. The helminth epidermis, or tegument, plays important roles in protection and nutrient acquisition; cestodes, in fact, completely lack a gastrointestinal tract and absorb all nutritive material through the tegument. Perhaps not surprisingly, the cestode tegument bears certain resemblances to the mucosal epithelium of the vertebrate small intestine, including the possession of a microvillous brush border upon the surface of the ectocytoplasm. In contrast to the intestinal epithelial cell, however, very little is known concerning the nature and organization of the cytoskeleton within the helminth epidermis. Therefore, a number of different microscopical preparative techniques were used to examine the tegument of the tapeworm Hymenolepis diminuta for the presence and distribution of microfilaments, intermediate filaments, and microtubules. It was found that both actin-containing microfilaments and intermediate-sized filaments are present but are restricted to specific locations along the plasmalemmae of the ectocytoplasm. In contrast, microtubules are found throughout the tegument, and are concentrated in the supranuclear regions of the perikarya and in the cytoplasmic bridges interconnecting the perikarya and ectocytoplasm. Unlike brush borders of most other epithelia, the cestode epidermal brush border lacks a filamentous terminal web and is instead associated with microtubules. A network of fine filaments, 5-8 nm in diameter but distinct from actin-containing microfilaments, runs throughout the ectocytoplasm and appears to interlink tegumental vesicles. These fine filaments may represent the primary "skeletal" system responsible for maintaining the structure of the tegumental cytoplasm.

Animals↗
PubMed1988

Acid phosphatase activity in the isolated brush border membrane of the tapeworm, Hymenolepis diminuta: partial characterization and differentiation from the alkaline phosphatase activity.

The isolated brush border membrane of the tapeworm, Hymenolepis diminuta, hydrolyzes p-nitrophenyl phosphate over a broad pH range. Acid phosphatase activity (pH optimum at 4.0) is inhibited specifically by sodium dodecyl sulfate (SDS) and NaF, while the alkaline phosphatase activity (pH optimum at 8.8) is inhibited specifically by levamisole, 2-mercaptoethanol, and ethylenediaminetetra-acetate (EDTA). These two phosphatase activities are further differentiated in that (1) there is a rapid decrease in alkaline phosphatase activity when the membrane preparation is incubated at pH 4.0, while there is little loss of acid phosphatase activity, and (2) the alkaline phosphatase activity is solubilized with no loss of activity when the membrane is treated with Triton X-100, while such treatment causes a significant loss of acid phosphatase activity. Both activities are nonspecific and hydrolyze a variety of phosphorylated compounds, but the relative activities of the two phosphatases against these substrates vary significantly.

Acid Phosphatase↗
PubMed1989

Competitive, uncompetitive, and mixed inhibitors of the alkaline phosphatase activity associated with the isolated brush border membrane of the tapeworm Hymenolepis diminuta.

Several compounds were tested as inhibitors of the alkaline phosphatase (AlkPase) activity associated with the isolated brush border membrane of the tapeworm, Hymenolepis diminuta. Molybdate, arsenate, arsenite and beta-glycerophosphate (BGP) were competitive inhibitors of the hydrolysis of p-nitrophenyl phosphate, while levamisole and clorsulon were uncompetitive and mixed inhibitors, respectively. Molybdate was also a competitive inhibitor of the hydrolysis of BGP and 5'-adenosine monophosphate, and levamisole was an uncompetitive inhibitor of BGP hydrolysis. The apparent inhibitor constants (Ki') for molybdate and levamisole were virtually identical regardless of the substrate, and these data support the hypothesis that the AlkPase activity is represented by a single membrane-bound enzyme with low substrate specificity. Quinacrine, Hg2+, and ethylenediaminetetraacetate were also potent inhibitors of the AlkPase activity, but the mechanisms by which these latter three inhibitors function were not clear.

Alkaline Phosphatase↗
PubMed1987

Magnetic resonance imaging of parasitic tapeworm larvae Taenia crassiceps cysticerci in the peritoneal cavity of mice.

Because of their long T2 relaxation time (400 ms), larvae of the tapeworm Taenia crassiceps can be distinctly imaged in the mouse peritoneal cavity by NMR. An echo time of 400 ms sharply contrasted the parasites against the surrounding abdominal organs. A rapid, quantitative assay for parasite load can be obtained by recording the amplitude of a spin echo with no applied gradients at an echo time of 400-1000 ms. The T2 of the vesicular fluid of the human parasite Taenia solium was also long (600 ms), indicating that the same approach (long TE and long TR) can be used to image this parasite for diagnosis of human cysticercosis by NMR imaging.

Animals↗
PubMed2004

Tsp36, a tapeworm small heat-shock protein with a duplicated alpha-crystallin domain, forms dimers and tetramers with good chaperone-like activity.

Small heat shock proteins (sHSPs), which range in monomer size between 12 and 42 kDa, are characterized by a conserved C-terminal alpha-crystallin domain of 80-100 residues. They generally form large homo- or heteromeric complexes, and typically have in vitro chaperone-like activity, keeping unfolding proteins in solution. A special type of sHSP, with a duplicated alpha-crystallin domain, is present in parasitic flatworms (Platyhelminthes). Considering that an alpha-crystallin domain is essential for the oligomerization and chaperone-like properties of sHSPs, we characterized Tsp36 from the tapeworm Taenia saginata. Both wild-type Tsp36 and a mutant (Tsp36C-->R) in which the single cysteine has been replaced by arginine were expressed and purified. Far-UV CD measurements of Tsp36 were in agreement with secondary structure predictions, which indicated alpha-helical structure in the N-terminal region and the expected beta-sandwich structure for the two alpha-crystallin domains. Gel permeation chromatography and nano-ESI-MS showed that wild type Tsp36 forms dimers in a reducing environment, and tetramers in a non-reducing environment. The tetramers are stabilized by disulfide bridges involving a large proportion of the Tsp36 monomers. Tsp36C-->R exclusively occurs as dimers according to gel permeation chromatography, while the nondisulfide bonded fraction of wild type Tsp36 dissociates from tetramers into dimers under nonreducing conditions at increased temperature (43 degrees C). The tetrameric form of Tsp36 has a greater chaperone-like activity than the dimeric form.

Amino Acid Sequence↗
PubMed1993

GNFFRFamide: a novel FMRFamide-immunoreactive peptide isolated from the sheep tapeworm, Moniezia expansa.

The widespread distribution of FMRFamide-immunoreactivity in platyhelminth nervous systems has been demonstrated immunocytochemically. Here we report the isolation and primary structure of the first platyhelminth FMRFamide-related peptide (FaRP) from the tapeworm, Moniezia expansa. The peptide was found to have a molecular mass of 785 Da and a primary structure of Gly-Asn-Phe-Phe-Arg- Phe-NH2 (GNFFRFamide). Acid alcohol extracts of this platyhelminth contained only this single FaRP which had a phenylalanyl (F) residue in the variable position 3 from the C-terminal occupied by either methionyl (M), leucyl (L) or isoleucyl (I) residues in most other FaRPs.

Amino Acid Sequence↗
PubMed2001

Interrelationships and evolution of the tapeworms (Platyhelminthes: Cestoda).

Interrelationships of the tapeworms (Platyhelminthes: Cestoda) were examined by use of small (SSU) and large (LSU) subunit ribosomal DNA sequences and morphological characters. Fifty new complete SSU sequences were added to 21 sequences previously determined, and 71 new LSU (D1-D3) sequences were determined for the complementary set of taxa representing each of the major lineages of cestodes as currently understood. New sequences were determined for three amphilinidean taxa, but were removed from both alignments due to their excessively high degree of divergence from other cestode sequences. A morphological character matrix coded for supraspecific taxa was constructed by the modification of matrices from recently published studies. Maximum-parsimony (MP) analyses were performed on the LSU, SSU, LSU+SSU, and morphological data partitions, and minimum-evolution (ME) analyses utilizing a general time reversible model of nucleotide substitution including estimates of among-site rate heterogeneity were performed on the molecular data partitions. Resulting topologies were rooted at the node separating the Gyrocotylidea from the Eucestoda. The LSU data were found to be more informative than the SSU data and were more consistent with inferences from morphology, although nodal support was generally weak for most basal nodes. One class of transitions was found to be saturated for comparisons between the most distantly related taxa (gyrocotylideans vs cyclophyllideans and tetrabothriideans). Differences in the topologies resulting from MP and ME analyses were not statistically significant. Nonstrobilate orders formed the basal lineages of trees resulting from analysis of LSU data and morphology. Difossate orders were basal to tetrafossate orders, the latter of which formed a strongly supported clade. A clade including the orders Cyclophyllidea, Nippotaeniidea, and Tetrabothriidea was supported by all data partitions and methods of analysis. Paraphyly of the orders Pseudophyllidea, Tetraphyllidea, and Trypanorhyncha was consistent among the molecular data partitions. Inferences are made regarding a monozoic (nonsegmented) origin of the Eucestoda as represented by the Caryophyllidea and for the evolution of the strobilate and acetabulate/tetrafossate conditions having evolved in a stepwise pattern.

Animals↗
PubMed1987

Localization of glycoconjugates at the tegument of the tapeworms Hymenolepis nana and H. microstoma with gold labelled lectins.

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.

Animals↗
PubMed1979

Studies on the embryogenesis of the tapeworm Cittotaenia variabilis (Stiles, 1895) using transmission and scanning electron microscopy.

The embryogenesis of the tapeworm Cittotaenia variabilis from the oocyte to the oncosphere is followed using scanning electron microscopy (SEM) in conjunction with ethanol cryofracture. Transmission electron micrographs and histochemistry are used to corroborate the inferences drawn from the SEM studies. Evidence is given for oocyte granules, the uterine epithelium, and the outer envelope as sources of components for the outer capsule. The contributions and senescence of the inner envelope and its relationship to the embryophore are given.

Animals↗
PubMed1991

Skin the tapeworms before you stain their nervous system! A new method for whole-mount immunocytochemistry.

A new method for making whole-mount immunocytochemical preparations of thick-skinned tapeworms is described. The tough tegument of the worms, which is impermeable to primary and secondary antisera, is removed by placing live worms in distilled water for 5-8 h, during which period the tegument is shed. The worms are thereafter fixed and stained as whole specimens using fluorescence immunocytochemical techniques. Both the main nervous structures and the finest neuronal details are revealed by this technique. Several types of antisera combinations are used. Diphyllobothrium dendriticum and Eubothrium crassum served as model organisms in this study.

Animals↗