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PubMed2003

STAT-6 is an absolute requirement for murine rejection of Hymenolepis diminuta.

Infection with helminth parasites typically evokes a T helper 2-cell response in the mammalian host. Interleukin (IL)-4 and IL-13 are important in the rapid expulsion of parasitic nematodes, with the absence of either cytokine being compensated for by the other. However, the IL-4 and IL-13 common signaling molecule, signal transducer and activator of transcription 6 (STAT-6) appears to be mandatory for the spontaneous expulsion of enteric helminths. Mice genetically deficient in IL-4, IL-13, or STAT-6 were infected with the cestode Hymenolepis diminuta and worm infectivity and jejunal goblet cell responses assessed 12-18 days postinfection (PI). Only the STAT-6 knockout (KO) animals harbored adult worms; neither gravid adult nor stunted H. diminuta was obtained from the infected IL-4 KO or IL-13 KO mice > or = 12 days PI. Also, the establishment of worms in the intestine of STAT-6 KO animals was associated with a reduced goblet cell response. These findings support the hypothesis that increased mucin production is an important part of the host response to tapeworm infection and that functional STAT-6 signaling may be an absolute requirement for the rejection of intestinal cestodes and thus, helminth parasites in general.

Animals↗
PubMed2004

Helminth parasites of the tropical gar, Atractosteus tropicus Gill, from Tabasco, Mexico.

A total of 8 helminth species were recorded in an examination of 43 tropical gar, Atractosteus tropicus Gill, collected at the Pantanos de Centla Biosphere Reserve, Tabasco, Mexico. The parasite species included 1 adult trematode, 3 metacercariae, 1 cestode, 1 adult nematode, and 2 nematode larvae. Six of these 8 species were rare, with low prevalence (< 17%) and abundance (< 1.0 helminths per examined fish). The larvae of Contracaecum sp. were the most abundant in the sample, constituting 60% of the total helminths (64% prevalence, 3.8 +/- 5.2 abundance), followed by the cestode Proteocephalus singularis, constituting 18% of the worms (30.5% prevalence, 1.1 +/- 3.0 abundance). Species richness, individual parasite abundance, and diversity were low in the infracommunities. The recording of 3 specialist species in the tropical gar confirms that the helminth fauna of gar has an appreciable degree of specificity. This study indicates the importance of ecological determinants of richness in helminth communities of the tropical gar.

Animals↗
PubMed2003

Helminth community structure of sympatric eastern American toad, Bufo americanus americanus, northern leopard frog, Rana pipiens, and blue-spotted salamander, Ambystoma laterale, from southeastern Wisconsin.

One-hundred twelve amphibians, including 51 blue-spotted salamanders, Ambystoma laterale, 30 eastern American toads, Bufo americanus americanus, and 31 northern leopard frogs, Rana pipiens, were collected during April-October 1996 from Waukesha County, Wisconsin and examined for helminth parasites. The helminth compound community of this amphibian assemblage consisted of at least 10 species: 9 in American toads, 8 in leopard frogs, and 3 in blue-spotted salamanders. American toads shared 7 species with leopard frogs, and 2 species occurred in all 3 host species. Although there was a high degree of helminth species overlap among these sympatric amphibians, statistically significant differences were found among host species and percent of indirect or direct-life cycle parasites of amphibian species individual component communities (chi2 = 1,015, P < 0.001). American toads had a higher relative abundance of nematodes, 59%, than larval cestodes, 31%, and larval and adult trematodes, 10%, whereas leopard frogs had a higher relative abundance of larval cestodes, 71.3%, and larval and adult trematodes, 25.3%, than nematodes 3.4%. This is related to ecological differences in habitat and dietary preferences between these 2 anuran species. Helminth communities of blue-spotted salamanders were depauperate and were dominated by larval trematodes, 94%, and few nematodes, 6%. Low helminth species richness in this host species is related to this salamander's relatively small host body size, smaller gape size, lower vagility, and more fossorial habitat preference than the other 2 anuran species. Adult leopard frogs and toads had significantly higher mean helminth species richness than metamorphs, but there was no significant difference in mean helminth species richness among adult and metamorph blue-spotted salamanders. Considering adult helminths, the low species richness and low vagility of caudatans as compared with anurans suggest that local factors may be more important in structuring caudatan helminth communities of salamanders than of anuran hosts. Helminth species infecting salamanders may be more clumped in their geographic distribution as compared with anurans, and the role of other hosts and their parasites at the compound community level may be important in structuring helminth communities of salamanders.

Ambystoma↗
PubMed1997

Anthelmintics. A comparative review of their clinical pharmacology.

Virtually all the important helminth infections in humans can be treated with one of 5 anthelmintics currently in use: albendazole, mebendazole, diethylcarbamazine, ivermectin and praziquantel. These drugs are vital not only for the treatment of individual infections, but also useful in controlling transmission of the more common infections. This article reviews briefly the pharmacology of these 5 drugs, and then discusses current issues in the use of anthelmintics in the treatment and/or control of soil-transmitted nematode infections, filariasis, onchocerciasis, schistosomiasis (and other trematode infections), neurocysticercosis and hydatidosis. Mebendazole and albendazole are most effective against intestinal nematodes, but are contraindicated during the first trimester of pregnancy. The efficacy of prolonged therapy with these 2 drugs for treatment of larval cestode infections has not yet been established. Diethylcarbamazine is widely used to treat and control lymphatic filariasis, but adverse effects related to death of microfilariae or damage to adult worms may be marked. While ivermectin has been used in the treatment of patients with onchocerciasis, it is also undergoing investigation against lymphatic filariae. Praziquantel, used to treat schistosome infections, is also effective in other trematode infections and adult cestode infections.

Anthelmintics↗
PubMed1984

Serological diagnosis and post-operative surveillance of human hydatid disease. II. The enzyme-linked immunosorbent assay (ELISA) using various antigens.

The ELISA using a urease conjugated antibody and 3 antigen preparations was examined for sensitivity and specificity in hydatid diagnosis. Four groups of sera tested were: 80 samples from patients with confirmed hydatid infection; 51 latex agglutination test (LA) +ve and immunoelectrophoresis test (IEP) -ve sera from patients with miscellaneous symptoms or disorders other than hydatid disease; 195 'normal' sera from healthy donors; 115 sera from persons infected with other parasites. Antigens tested included crude sheep hydatid cyst fluid (CSHCF), CSHCF partially purified by salt fractionation (PPSHCF) and CSHCF purified by sequential affinity chromatography depletion with rabbit anti-sheep IgG, 3EgH 29-2 anti-Echinococcus monoclonal antibody and 'normal' sheep Ig (ADSHCF). All 3 antigens showed high sensitivity in detecting antibody in serum from hydatid-infected patients, and gave excellent discrimination between these samples and the LA +ve IEP -ve sera and the 'normal' sera. Cross-reactions occurred with antibodies in the sera of patients with other parasitic infections, especially other larval cestodes and filarial parasites. Superior specificity was achieved with both CSHCF and ADSHCF, and ADSHCF reacted only with a single serum sample from an E. multilocularis patient. It was concluded that a combination of ELISA and IEP was useful for the diagnosis of hydatid disease, that ELISA at a single dilution could be useful as a screening test where other larval cestode infections were not prevalent and that ELISA was not of value for post-operative surveillance.

Antibodies↗
PubMed1978

Glutathione conjugation of some xenobiotics by Ascaris suum and Moniezia expansa.

1. The cestode Moniezia expansa and the nematode Ascaris suum both possess enzymes catalysing the conjugation of glutathione (GSH) with 1-chloro-2,4-dinitrobenzene. 2. The GSH-S-aryl transferase (GSH-S-transferase A) was present in the cytosol of the cestode proglottids and of the nematode intestinal epithelial cells. Other tissues did not contain measurable activity. The enzymes from both species had mol. wt. of about 37 000 and broad pH optima around pH 8.3. Both enzymes were inhibited by Cu2+, Fe3+ and Hg2+ at 1 mM and stimulated by Co2+. 3. Neither M. expansa nor A. suum possessed measurable DDT dehydrochlorinase activity. GSH-S-epoxide transferase (GSH-S-transferase E) activity was indicated in both species; neither species effected the conjugation of bromo- or chlorobenzene. 4. Halogenated anthelmintics were not metabolized to GSH conjugates in the helminths studied and did not inhibit GSH-S-aryltransferase activity towards chlorodinitrobenzene.

Animals↗
PubMed1978

The localization and some properties of the acetylsalicylic acid O-deacetylases of Ascaris lumbricoides var suum and Moniezia expansa.

1. Enzymes hydrolysing acetylsalicylic acid were found in the cytosol of the cestode, Moniezia expansa, and in the cytosol of the intestinal epithelial cells and cytosol of the reproductive tract of the nematode, Ascaris lumbricoides var suum. 2. Enzymes hydrolysing 2-naphthyl acetate and 4-methylumbelliferyl acetate were found throughout the proglottid of the cestode and in the reproductive tract, intestine, mesenchyme fluid and cuticle of the nematode. These enzymes had mol. wt. of 30 000-300 000 whereas those hydrolysing acetylsalicylic acid in both species had mol. wt. of about 87 000. 3. The acetylsalicylic acid hydrolases from both helminths showed pH optima of about 7.0, and activity was enhanced by Ca2+ and low-mol. wt. thiols. Cu2+, Cd2+, Hg2+, Zn2+, La3+, F- and EDTA at 1 mM inhibited activity. N-Ethylmaleimide, p-chloromercuribenzoate, haloxon and paraoxon also inhibited hydrolase activity.

Acetyltransferases↗
PubMed1979

The metabolism of the anthelmintics clioxanide and resorantel and related compounds in vitro by Moniezia expansa, Ascaris suum and mouse- and sheep-liver enzymes.

1. Clioxanide and related compounds were deacetylated by the cestode Moniezia expansa, the nematode Ascaris suum, by enzymes prepared from these species and by mouse- and sheep-liver homogenates. Deacetylase activity was found in the cytosol of cestode proglottids throughout the strobila, and in the cytosol of nematode intestinal cells and reproductive tract. 2. The O-deacetylases from both helminths showed similar pH optima of about 7.0. Activity was enhanced by Ca2+ and low molecular weight thiols. Cu2+, Cd2+, Hg2+, Zn2+, and La2+ inhibited the deacetylation of clioxanide. 3. Resorantel and clioxanide were not hydrolysed at the amide bond by helminth or mammalian enzymes. 4. Resorantel was hydroxylated by mammalian microsomal enzymes, but helminths did not modify the molecule.

Anilides↗
PubMed1966

Studies on transaminase reactions in some parasitic helminths.

By an application of Sigma-Frankel methods, two transaminase systems, glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase, were found to operate at a mesurable rate in 2 species of nematodes(Ascaris lumbricoides and Ascaridia galli), 5 species of trematodes (Clonorchis sinensis, Fasciola hepatica, Eurytrema pancreaticum, Paramphistomum cervi and Paragonimus westermani) and 5 kinds of cestodes (Diphyllobothrium mansoni, Dipylidium caninum, Taenia pisiformis, Cysticercus cellulosae and Cysticercus pisiformis). A comparison was made of the transamination reactions in nematodes and those of trematodes and cestodes. And the significance of transaminase in these parasites is discussed in relation to protein synthesis and its utilization.

Journal Article↗
PubMed1967

[Studies On Lactic Dehydrogenase Activity In Parasitic Helminths]

A series of experiments was performed to determine the lactic dehydrogenase activity of various parasitic helminths. The enzyme activity was determined by the modified method of Wroblewshi and LaDue (1955) using tissue homogenate of 16 kinds of worm parasites. The worms were mostly collected alive from local abattoir and removed from the organ or tissues of the naturally infected animal host and some materials were also obtained from the human host. They were thoroughly washed and homogenized in chilled glass tissue grinder, and then centrifuged. The supernatants were designated as enzyme preparations, and their enzyme activity was measured by spectrophotometry at the wave length of 340 millimicron. In order to know the effects of temperature and substrate concentration on the enzyme activity, the extinction of reduced Coenzyme I(NADH) was measured at the various conditions of incubation temperature and substrate concentration. The results of this experiments were as follows: 1. The lactic dehydrogenase activity occurred over all kinds of parasites used in this study. 2. Most worms of nematodes and trematodes displayed their maximum activity in the range of pH 2.7~3.5, and cestodes revealed their maximum activity in the ranges of both pH 2.7~3.5 and pH 7.4. 3. In nematodes and trematodes, the lactic dehydrogenase activity increased slowly as incubation temperature increases except in the case of Eurytrema pancreaticum, while the activity in cestodes decreased inversely. 4. The lactic dehydrogenase activity increased in proportion to the increase of substrate concentration in most of worm parasites.

Journal Article↗
PubMed1980

Fine Structure Of Cysticercus Celluosae From Human Brain.

A transmission electron microscopic study was conducted in order to know basic tegumental structure of Cysticercus cellulosae which was obtained from the ventricles of human brain. In general, the electron microscopic appearance of the tegument resembled that of the body wall of adult and larval forms of other cestodes. The tegument both of the parenchymatous portion (scolex and spiral canal) and bladder portion consisted of such components, i.e., an outer vesicular layer with microtriches, and an inner fibrous layer. The subtegumental tissue below the fibrous layer was filled with muscle bundles and tegumental cells. The surface of the larva was covered by the microtriches of two distictly different types. The characteristic pyramid-shaped "tetrahedral" form was observed on the surface of the scolex portion, whereas the elongated, slender "filamentous" microtriches were distributed on the regions of the spiral canal and bladder portion. The tegumental and subtegumental tissues varied in thickenss from one region to the next. The possibility of application in making differential diagnosis from other larval cestodes and possible fuction of this larval tegument were discussed.

Journal Article↗
PubMed1983

[Studies On The Bladder Worm, Cysticercus Cellulosae: The Ultrastructure Of C. Cellulosae]

An electron microscopic study was performed to know the basic tegumental structure of Cysticercus cellulosae. The scolex and bladder portions of cysticerci (human and porcine strains) were prepared for transmission and scanning electron microscopy by conventional procedures. In general, the tegument of C. cellulosae showed the basic ultrastructure of cestode tegument on electron micrographs. The teguments of both scolex and bladder portions consisted of such components i.e., an outer vesicular layer with numerous microtriches and inner fibrous layer. Below the fibrous layer, there were layers of muscle bundles and tegumental cells. The microtriches which covered the surface of cysticercus revealed two distinctly different shapes. The characteristic bladder-like, elongated pyramid shaped 'tetrahedral form' was observed on the surface of the scolex portion, whereas the elongated cylindrical 'filamentous form' was distributed on the surface of bladder portion. In spite of the difference of isolated host and location, the cysticerci showed the same result. But dimensional variations of the tegument according to topography of the worm were observed. The possibility of application in making differential diagnosis from other larval cestodes and possible functions of this larval tegument were discussed.

Journal Article↗
PubMed2000

Examination of gastrointestinal helminth in livestock grazing in grassland of Bangladesh.

To determine association of grassland with parasitic diseases of livestock in Bangladesh, the 'Tracer' animals (two cow calves and two goats) were released for a month in a grassland used for communal grazing of livestock near school premise in Kanthal, Trishal, Mymensingh, Bangladesh. After slaughtering of the tracer animals, their gastrointestinal tract examination revealed six species of nematode and one cestode. The nematode species were Haemonchus contortus, Trichostrongylus axei, Mecistocirrus digitatus, Oesophagostomum spp., Trichuris spp. and Bunostomum sp. The cestode was one of the genus Moniezia. With this preliminary study, grasslands are thought to be one of the main sources of gastrointestinal parasitic diseases of livestock in Bangladesh.

Animals↗
PubMed2006

Cloning of the novel putative apoptosis-related gene of Spirometra erinacei (Order Pseudophyllidae).

We postulated that apolysis was processed in accordance with apoptotic changes occurring in a cestode, Spirometra erinacei (Pseudophyllidea). We cloned the novel putative apoptosis-associated gene from S. erinacei via screening of a S. erinacei cDNA library with a ced-3 gene (activator of apoptosis) probe from Caenorhabditis elegans. We identified a 261-bp cDNA sequence, which encodes for an 86-amino acid protein. The cloned gene expression was observed in the neck and gravid proglottids via Northern blotting, using cloned cDNA inserts as probes, but the clone was not expressed in any of other tissues. We suggest that this gene may be involved in the apolysis of S. erinacei during normal tissue development and differentiation in cestode parasites.

Amino Acid Sequence↗
PubMed2002

Insights into fish host-parasite trophic relationships revealed by stable isotope analysis.

Trophic relationships between 10 species of fish host and their associated nematode, cestode, and copepod parasites were investigated using stable isotopes of carbon and nitrogen. Nematodes and cestodes were consistently depleted in 15N with respect to their host, and such fractionation patterns are unlike those conventionally observed between consumers and their diets. Species of copepod parasite were sometimes depleted and sometimes enriched in 15N with respect to fish hosts, and this confirms earlier reports that the nature and magnitude of ectoparasite-host fractionations can vary. Significant differences in delta15N and delta13C were observed among fish tissues, and the isotopic signature of parasites did not always closely correspond to that of the tissue with which the parasite was found most closely associated, or on which the parasite was thought to be feeding. Several possible explanations are considered for such discrepancies, including selective feeding on specific amino acids or lipids, migration of the parasite among different fish tissues, changes in the metabolism of the parasite associated with life history and migration between different host animals.

Animals↗
PubMed1981

Characteristics of the larval Echinococcus vogeli Rausch and Bernstein, 1972 in the natural intermediate host, the paca, Cuniculus paca L. (Rodentia: Dasyproctidae).

In Colombia, the natural intermediate host of Echinococcus vogeli Rausch and Bernstein, 1972 is the paca, Cuniculus paca L. (Rodentia: Dasyproctidae). The larval cestode develops in the liver of the host, where it usually is situated superficially, partly exposed beneath Glisson's capsule. The infective larva consists of a subspherical to asymmetrical, fluid-filled vesicle, up to 30 mm in diameter, enclosed by a thick laminated membrane. It typically contains numerous chambers, often interconnected, produced by endogenous proliferation of germinal and laminated tissue, within which brood capsules arise in an irregular pattern from the germinal layer. Invasive growth by means of exogenous proliferation, typical of infections in man, was not observed in the natural intermediate host. The development of the larval cestode is described on the basis of material from pacas, supplemented by observations on early-stage lesions in experimentally infected nutrias, Myocastor coypus (Molina) (Rodentia: Capromyidae). The tissue response is characterized for early-stage, mature (infective), and degenerating larvae in the comparatively long-lived intermediate host. In addition to previously reported differences in size and form of rostellar hooks, other morphologic characteristics are defined by which the larval stage of E. vogeli is distinguished from that of E. oligarthrus (Diesing, 1863). Pathogenesis by the larval E. vogeli in man, like that by the larval E. multilocularis Leuckart, 1863, is the consequence of atypical proliferation of vesicles attributable to parasite-host incompatibility.

Animals↗
PubMed1987

Spontaneous death of Echinococcus multilocularis: cases diagnosed serologically (by Em2 ELISA) and clinical significance.

Nine cases of asymptomatic alveolar hydatid disease (AHD) of the liver were diagnosed in 1985 among Eskimos from the endemic region of western Alaska. The patients were identified by screening with the enzyme-linked immunosorbent assay, using purified Echinococcus multilocularis antigen (Em2 ELISA). Five patients, and one diagnosed earlier (1979), were found to have lesions in which the larval E. multilocularis had died spontaneously at an early stage of infection. Viability was assessed histologically; by the avidin-biotin immunohistochemical method; and in vivo through intraperitoneal inoculation of membranes of the larval cestode into red-backed voles, Clethrionomys rutilus. The results were in agreement with the clinical impression, based on findings by computerized tomography and ultrasound scanning, and on the macroscopic appearance of the lesions, that the cestode was dead. Spontaneous death of E. multilocularis in humans has not been previously reported. The findings show that the Em2 ELISA may be positive in patients having lesions of AHD in which the etiologic agent is no longer viable.

Aged↗
PubMed1987

Albendazole therapy in alveolar hydatid disease: a report of favorable results in two patients after short-term therapy.

Albendazole was administered preoperatively to two patients with active alveolar hydatid disease for 58 and 84 days. Vesicles of larval Echinococcus multilocularis obtained from surgical tissues were inoculated into red-backed voles for in vivo testing viability. No proliferation of the larval cestode had occurred when the animals were dissected three months post-inoculation. These findings suggest that short-term therapy with albendazole was effective in killing the larval cestode in these two cases. Albendazole was found to be hepatotoxic but resulting transaminase abnormalities have been reversible. Close monitoring of liver function and hematology is essential in patients under albendazole therapy.

Adult↗