Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CESTODES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,459 records · Page 81Linked to original sources
PubMed2002

Purification and localization of a 10 kDa calcareous corpuscle binding protein of Spirometra mansoni plerocercoid.

In cestode parasites, calcareous corpuscles are thought to be associated with a number of intracellular physiologies by regulating the trafficking of mineral components. We previously separated these particular components by Ficoll, and their binding proteins of 10 kDa and 35 kDa in the Spirometra mansoni plerocercoid (sparganum). In the present study, we purified a 10 kDa protein employing octyl-Sepharose CL-4B affinity chromatography. Anti-serum raised against the purified protein showed specific reactions to the calcareous corpuscles of the worm section by immunohistochemistry, and recognized the 10 kDa protein by immunoblotting.

Animals↗
PubMed2003

Effects of conspecifics and heterospecifics on individual worm mass in four helminth species parasitic in fish.

Intraspecific and interspecific effects on the growth and body size of helminths are rarely studied in natural situations, yet knowing what determines helminth sizes and thus fecundity is crucial to our understanding of helminth ecology and epidemiology. The determinants of average individual worm mass were investigated in four common species of helminths parasitic in trout, Salmo trutta. In the acanthocephalan Echinorhynchus truttae, there was a negative relationship between the intensity of infection by conspecifics and average individual worm size. However, in the acanthocephalans Pomphorhynchus laevis and Acanthocephalus anguillae and in the cestode Cyathocephalus truncatus, the relationship was positive: individual worms were larger on average when co-occurring with many conspecifics than when co-occurring with very few. In addition, the average mass of individual C. truncatus in a host decreased as the total mass of other helminth species in the same host increased. This interspecific effect involves the whole helminth community, as the combined effect of all other helminth species is a better predictor of reduced mass in C. truncatus than the mass of any other species taken on its own. These results illustrate the importance of considering helminth interactions and helminth growth in a natural setting.

Acanthocephala↗
PubMed2003

A molecular study of Eubothrium rugosum (Batsch, 1786) (Cestoda: Pseudophyllidea) using ITS rDNA sequences, with notes on the distribution and intraspecific sequence variation of Eubothrium crassum (Bloch, 1779).

The internal transcribed spacers (ITS-1 and ITS-2) of the ribosomal DNA (rDNA) of fish cestodes of the genus Eubothrium were sequenced. The ITS sequences of Eubothrium rugosum were determined and compared with previously analysed congeneric species, Eubothrium crassum and Eubothrium salvelini. The ITS-1 sequences of E. rugosum and E. crassum were 535 bp long, the length of E. salvelini ITS-1 was 536 bp. The ITS-2 region was found to be 403 bp in E. rugosum and E. crassum, and 401-402 bp in E. salvelini. The ITS-1 region of E. rugosum was closer to E. salvelini (identity 98.9-99.1%) than to E. crassum(97.9-98.1%), while the sequence similarity within the ITS-2 region was almost identical (97.5-98.0% for E. crassum; 97.7-98.3% for E. salvelini). Several restriction enzymes were found to be suitable for the differentiation of the three Eubothrium species by PCR-RFLP. The intraspecific sequence variation of E. crassum from different fish hosts (freshwater and marine) and European regions was very low, 0.2% for ITS-1 and 0.5% for ITS-2. Analysis of the ITS sequences of specimens from rainbow trout from three localities in Scotland revealed that both E. crassum and E. salvelini are present in this fish host.

Animals↗
PubMed2003

Ultrastructure of the early rostellum of Silurotaenia siluri (Batsch, 1786) (Cestoda: Proteocephalidae).

The neodermis of the whole early rostellum of Silurotaenia siluri (Batsch, 1786) bears filamentous microtriches. At the base, there are five to six irregular rows of hooks and spine-like microtriches. The rostellar hooks of S. siluri originate through the enlargement of microtriches. Electron-dense hook substance is deposited along the edges of the microthrix to form the hook blade and basal plate. The blade does not become hollow as in the cyclophyllidean cestodes. The basal plate of the hook, corresponding to the handle and the guard of Cyclophyllidea, is formed by the deposition of hook substance around the base of the microthrix. Within the centre of the base, only a narrow cleft-like core is occupied by distal cytoplasm. The hook bases are more deeply inserted into the distal cytoplasm, as the bases of the spine-like microtriches are localized on the rostellum below the rows of hooks. No hemidesmosomes, fixing the hook base to the basal lamina, are present. Eccrine gland cells and uniciliate and nonciliate sensory receptors of the primitive rostellum are described.

Animals↗
PubMed2003

The toxicity of praziquantel against Mesocestoides vogae (syn. corti) tetrathyridia can be assessed using a novel in vitro system.

We recently standardised Mesocestoides vogae (syn. corti) tetrathyridia cultures in the presence of sodium taurocholate. Parasite clustering and segmentation were observed as taurocholate-dependent effects in biphasic and monophasic media, respectively, and both were inhibited by a specific minimum inhibitory concentration (m.i.c.) of the cestocidal drugs albendazol and praziquantel. In the present study, we analysed the relationship between clustering inhibition and drug toxicity using praziquantel and a mouse experimental infection. In an "in vitro-in vivo" trial, a significant (ANOVA, P<0.05) reduction was observed in the infectivity of tetrathyridia previously cultured with praziquantel m.i.c. (0.06 micro g/ml) for 10 days. In an "in vivo-in vitro" trial, the clustering of tetrathyridia recovered from mice treated with praziquantel was found to be markedly reduced: 22%, compared with 83% cluster-containing wells of parasites from control mice. These results show that the outcome of infection and the suppression of taurocholate-induced clustering provide consistent indications of praziquantel toxicity against M. vogae, an observation confirmed by histological studies. The easily recorded clustering inhibition of M. vogae tetrathyridia in biphasic medium is a potentially useful system for the assessment of drug toxicity against cestode larvae.

Animals↗
PubMed2003

First occurrence of Mesocestoides sp. in a bird, the red-legged partridge, Alectoris rufa, in Spain.

Larvae of Mesocestoides sp. were found in the celomic cavity of one red-legged partridge (Alectoris rufa) from Azuara (Aragón, north-eastern Spain). This is the first report of this larval cestode occurring in birds from Spain. None of the other 36 partridges from this area nor 150 partridges from other Spanish localities were affected. The red-legged partridge does not seem to be an important link in the Mesocestoides sp. life-cycle.

Animals↗
PubMed2003

CD4+ and CD19+ splenocytes undergo apoptosis during an experimental murine infection with Taenia crassiceps.

The Taenia crassiceps cysticercus is a cestode that naturally and experimentally infects rodents in which it reproduces by budding. In the laboratory, a persistent cellular immunosuppression with a concomitant increasing load of parasites has been observed in experimentally infected BALB/cAnN mice. In this study, enhanced apoptosis was found in spleen cells from 30-day infected mice with a typical "ladder-patterned" DNA fragmentation and an increase in phosphatidylserine expression. A characteristic poly-(ADP-ribose) polymerase cleavage indicates that this cell death is caspase-mediated. Apoptosis was detected in the CD4(+) and CD19(+) splenocytes of infected mice after in vitro stimulation with cysticercal antigens. Considering previous results on the crucial role that CD4(+) T cells play in controlling the extent of infection, apoptosis in this T-lymphocyte subpopulation induced by T. crassiceps cysticerci could be responsible for the immunosuppression that underlies parasite success.

Animals↗
PubMed2003

Intestinal helminths of a landlocked ringed seal (Phoca hispida saimensis) population in eastern Finland.

A small, landlocked, endangered ringed seal (Phoca hispida saimensis) population lives as a postglacial relict in Lake Saimaa in eastern Finland. In this study, the intestinal metazoans were examined from a total of 61 Saimaa seals found dead from 1981 to 2001. The helminth fauna was very depauperate. Only one acanthocephalan species, Corynosoma magdaleni, has been able to survive during isolation in the freshwater environment. In addition, only two cestode species were found: Diphyllobothrium ditretum and Schistocephalus sp. However, neither of these larvae developed in the ringed seals. As the newborn pups of Saimaa seals are nursed for about 2 months only one of them was infected by C. magdaleni. At 2-5 months the pups harboured worms; however, the mean intensity did not rise distinctively until the seals were adults. C. magdaleni infection increased with increasing age and the abundances were significantly different between the age groups. There was no correlation between the number of parasites and the adult seal body weight; however, seals weighing 36 kg or more carried the majority of the worms. The distribution of the parasites was aggregated; six seals carried 65% (n=1,182) of all worms (total n=1,809) and 26 seals were uninfected. Variation in the number of worms in individual seals may indicate differences in feeding behaviour and in the diet of seals, and/or variation in the immune status of the seals.

Acanthocephala↗
PubMed2003

Sustained-release praziquantel tablet: pharmacokinetics and the treatment of clonorchiasis in beagle dogs.

Praziquantel is rapidly absorbed and secreted; and thus fractional doses are recommended for the treatment of cestode and trematode infections. In the present study, we developed a new praziquantel tablet formula allowing sustained-release (SRP). In vitro dissolution of SRP tablets showed that praziquantel at 300 mg/tablet combined with hydroxypropyl methylcellulose dissolved completely at a constant rate over 10 h, whereas the conventional praziquantel tablet (PZQ) was only 40% dissolved. Pharmacokinetic studies in dogs confirmed that SRP was absorbed more slowly than PZQ. The mean value of the area under the concentration/time curve from 0 h to the final observation time, the maximum concentration in serum, and the time of maximum concentration in serum for SRP were 3,471,500 ng/min for 0.25 ml, 10,300 ng for 0.25 ml, and 192 min, while the values for PZQ were 688,600 ng/min for 0.25 ml, 2,500 ng for 0.25 ml, and 135 min. The cure rate in dogs with a heavy infection (500 metacercariae) treated with a single dose of SRP (150 mg/tablet) at 50 mg/kg was 80%, while in dogs treated with a single dose of SRP (300 mg/tablet) at 30 mg/kg it was 60%, and the cure rate with PZQ was 20%. In each case, the egg reduction rate was similar (over 90%). No abnormal liver functions or hepatic or renal pathologies were observed in dogs administered with SRP at 30 mg/kg. The SRP tablet showed sustained release and slow absorption; and it had an improved anthelmintic efficacy against Clonorchis sinensis in experimental dogs, compared with conventional praziquantel.

Animals↗
PubMed2003

The comparative metabolism of triclabendazole sulphoxide by triclabendazole-susceptible and triclabendazole-resistant Fasciola hepatica.

Benzimidazole anthelmintics are widely used against nematode, cestode and trematode parasites. The drugs undergo several enzyme-mediated reactions within the host animal that produce a number of metabolites. Although it has been shown that certain helminths, including Fasciola hepatica, can metabolise albendazole, nothing is known regarding the ability of the liver fluke to metabolise triclabendazole, which is the major flukicidal compound currently on the market. In the current study, adult triclabendazole-susceptible flukes were treated with triclabendazole sulphoxide in vitro, and the metabolism of the drug was monitored by high performance liquid chromatography. The data show that F. hepatica can metabolise triclabendazole sulphoxide into its relatively inert sulphone metabolite. Parallel experiments using triclabendazole-resistant flukes showed that the conversion of triclabendazole sulphoxide to triclabendazole sulphone was on average 20.29% greater in the resistant flukes compared with the susceptible flukes. The results are discussed with regard to the mechanism of triclabendazole resistance in F. hepatica.

Albendazole↗
PubMed2004

Helminth fauna of Falconiform and Strigiform birds of prey in Galicia, Northwest Spain.

This is a survey of the helminth fauna of 285 individuals of 14 species of birds of prey (Falconiformes and Strigiformes) from Galicia (northwest Spain), namely Buteo buteo, Accipiter nisus, A. gentilis, Milvus migrans, M. milvus, Pernis apivorus, Circus pygargus, Falco tinnunculus, F. peregrinus, F. subbuteo, Tyto alba, Strix aluco, Asio otus and Athene noctua. A total of 15 helminth species were detected, namely 8 nematodes ( Eucoleus dispar, Capillaria tenuissima, Synhimantus laticeps, Microtetrameres sp., Physaloptera alata, Procyrnea leptoptera, Hovorkonema variegatum and Porrocaecum angusticolle), 4 cestodes ( Cladotaenia globifera, Paruterina candelabraria and Mesocestoides sp.), 2 trematodes ( Neodiplostomum attenuatum and Strigea falconis), and 1 acanthocephalan ( Centrorhynchus globocaudatus). The helminth communities observed were basically similar, although there were marked differences in species richness, which was higher in falconiforms (except for A. gentilis) than in strigiforms. More specifically, species richness was highest in B. buteo (13 species), followed by A. nisus (11 species). In the falconiforms, the helminth species present generally exhibited a clear relationship with host diet. In the strigiforms, by contrast, species richness was lower than expected given the host's diet, suggesting that a different explanation is needed.

Animals↗
PubMed2004

Parasitic helminth fauna of the cutlass fish, Trichiurus lepturus L., and the differentiation of four anisakid nematode third-stage larvae by nuclear ribosomal DNA sequences.

The helminth fauna of the gastrointestinal tract and abdominal cavity of cutlass fish, Trichiurus lepturus L., off the Taiwanese coast of the north-western Pacific was investigated. The following helminths were found: (1) nematodes--Anisakis simplex, Hysterothylacium aduncum, Porrocaecum decipiens, Raphidascaris trichiuri; (2) digeneans--adult Lecithochirium trichiuri; and (3) cestodes-plerocercoids of Proteocephalus spp. The third-stage larvae of these four anisakid nematodes were characterized genetically using a molecular approach. The nuclear ribosomal DNA region spanning the first internal transcribed spacer (ITS-1), the 5.8S gene and the second internal transcribed spacer (ITS-2) was amplified and sequenced. Based on the sequence differences, a PCR-based restriction fragment length polymorphism method was established for the unequivocal delineation of the four species. Phylogenetic analysis showed that H. aduncum clustered with P. decipiens, whereas A. simplex was not closely related to these according to the nucleotide sequences of all rDNA.

Abdominal Cavity↗
PubMed2004

Molecular systematics of several cyclophyllid families (Cestoda) based on the analysis of 18S ribosomal DNA gene sequences.

The sequences of the 18S small subunit ribosomal DNA of five species of cyclophyllidean cestodes from the families Davaineidae, Anoplocephalidae and Dilepididae were determined. A species of tetrabothridid was also sequenced. These 18S sequences were combined with other available eucestode sequences in GenBank. From the 1,838 sites in the alignment, 375 bp (20%) were excluded from the analysis due to alignment issues inferred by manual inspection. Phylogenetic trees were obtained by maximum parsimony, neighbour-joining distance and maximum likelihood methods. Analyses showed that Cyclophyllidea is monophyletic and separate from Tetrabothrius spp. Lyruterina nigropunctata, which is now included in the family Paruterinidae, is more closely related to davaineids of the genus Raillietina than Pseudidiogenes nana (Davaineidae). P. nana and Choanotaenia infundibulum (Dilepididae) derive from the Davaineidae (or Raillietininae). The two species of Taenia (T. parva and T. pisiformis) formed a monophyletic sister group to the Davaineidae and Anoplocephalidae. The systematics of the Paruterinidae have been problematic and our results suggest a review of this family including other species with paruterine organ located in other families. The position of the Idiogeninae as a subfamily in the Davaineidae is also reviewed.

Animals↗
PubMed2004

Helminth parasites of Girardinichthys multiradiatus (Pisces: Goodeidae) in the upper Lerma River sub-basin, Mexico.

Thirteen helminth species were recorded during a helminthological examination of 754 Girardinichthys multiradiatus (Meek) (Pisces: Goodeidae) collected from 20 localities in the upper Lerma River sub-basin on the highland plateau of Mexico. The study constitutes a complete and extensive inventory of the helminth parasites of this freshwater fish species across its entire current geographic distribution. The collected species included one adult trematode, three metacercariae, one monogenean, one adult cestode, three metacestodes, three nematode larvae and one cystacanth. The records of the metacercariae of Tylodelphys sp. and Ochetosoma brevicaecum, the larvae of the nematodes Contracaecum sp. and Falcaustra sp. and the cystacanth of Polymorphus brevis are all new records for G. multiradiatus. The metacercariae of Tylodelphys sp. were the most widespread and prevalent species in the sample, being collected from 15 of the 20 sampling localities, with a prevalence of 3.2-72.2%. The data indicate the helminth parasite community of G. multiradiatus to be relatively poor when compared with the helminth communities of freshwater fish from other parts of Mexico. This community is subject to colonization by generalist helminth species, mostly transported by birds. A further component of this community consists of helminth species that have been introduced anthropogenically.

Acanthocephala↗
PubMed2004

Associations between fish reproductive cycle and the dynamics of metazoan parasite infection.

The parasite fauna of the stone loach (Barbatula barbatula) was investigated monthly from May to December 2001. Four parasite species were recorded: Gyrodactylus spp. (Monogenea), Tylodelphys clavata (Digenea), Proteocephalus sagittus (Cestoda), and Raphidascaris acus (Nematoda). The changes in the seasonal dynamics of parasite infection were investigated throughout the 8 months. The potential effect of the reproductive investment of the host, measured by gonad mass and gonado-somatic index (GSI), on the parasite infection was tested against the prediction that, during periods of high reproductive investment (beginning of the breeding period or forming gonads after breeding), the fish are more susceptible to parasite infection. Differences between parasite loads between genders were also hypothesized. Seasonal differences in infection were observed for all parasite species studied. The values of GSI showed a pattern of energy accumulation in the pre-reproductive period and at the beginning of breeding, a decrease during breeding, and an increase in the post-breeding period. A similar pattern was observed for parasite abundance, a strong or weak increase in spring and/or autumn and a decrease during summer (July and August). Positive correlations between the abundance of Gyrodactylus spp. and R. acus and both gonad mass and GSI were found in females after eliminating the effect of fish weight. Our results suggest that stone loach females are more susceptible to parasite infection in periods of higher reproductive investment. The main factor determining the infection of T. clavata was fish size. The abundance of P. sagittus was positively correlated with GSI in the total fish sample with no detectable effect of sex or fish weight. The increase in cestode infection in spring supports the hypothesis that the parasite life cycle could by synchronized with the beginning of host reproduction, probably induced by increasing fish hormone levels in the spring.

Animals↗
PubMed2005

Apoptosis patterns in experimental Taenia solium and Taenia crassiceps strobilae from golden hamsters.

Apoptosis or programmed cell death (PCD) patterns of two taeniid species, Taenia solium and Taenia crassiceps, were explored in adult tapeworms grown in golden hamsters. Animals were fed either ten viable T. solium cysticerci from naturally infected pigs or from T. crassiceps WFU strain maintained in Balb/c mice. Adult strobilae were recovered from the intestine at different times after infection and either frozen at -70 degrees C or fixed in paraformaldehyde-glutaraldehyde. Frozen sections were processed using the DNA fragmentation fluorescent TUNEL reagents and examined in an epifluorescent microscope. Fixed tissues were processed for light and electron microscopy. Typical apoptotic cells were found in the central core of scolex and strobilar tissues, mainly in the germinal tissue and subtegumentary areas. By the TUNEL technique, cells exhibited the characteristic fluorescent images of condensed nuclear chromatin. By light microscopy of thick sections stained with toluidine blue, we found a number of small rounded cells which had lost their cytoplasmic bridges and had shrunken nuclei with aggregated chromatin, cells which were found interspersed with normal syncytial cells. Similar cell morphology was confirmed by electron microscopy. Stunted viable worms, recovered with longer mature specimens, had very short strobilae and exhibited a large number of apoptotic cells in the germinal neck tissues. The results are consistent with the syncytial nature of these parasites, and strongly suggest that cell proliferation and PCD in these adult cestodes are continuous processes of the germinal tissue and tegumentary cytons.

Animals↗
PubMed2005

Transmission electron microscopy of the scolex and neck microtriches of Silurotaenia siluri (Batsch, 1786) (Cestoda: Proteocephalidea).

Microtriches on different parts of the scolex and neck of the gangesiine cestode Silurotaenia siluri (Batsch 1786) were studied. The neodermis of the central frontal scolex part (around the rostellar furrow) bears filamentous microtriches only. The lateral frontal part and the parts between and posterior to the suckers cover filamentous and spine-like microtriches. Within the suckers there are short spine-like microtriches with bases enforced by electron-dense ribs. The proximal neck part bears filamentous and spine-like microtriches, the middle part solitary distributed blade-like and spine-like microtriches among filamentous ones, and the distal part blade-like microtriches. The functions of different types of microtriches are discussed.

Animals↗
PubMed2005

New locality records for third-stage larvae of Anisakis simplex (sensu lato) (Nematoda: Ascaridoidea) in euphausiids Euphausia pacifica and Thysanoessa raschii from Prince William Sound, Alaska.

Five euphausiid species (n=41,037) were collected in October 1997 from Prince William Sound, Alaska, and examined for parasites. New locality records are claimed for third-stage larvae (L3) of whaleworm Anisakis simplex (sensu lato) in two (0.019%) of 10,437 Thysanoessa raschii, and in one (0.013%) of 7,443 Euphausia pacifica. The L3 were about 19.5, 21.3 and 30.5 mm long. L3 were absent from 8,026 T. inermis, 10,302 T. longipes and 4,829 T. spinifera collected at the same time, and from 6,648 euphausiids representing the five species collected in July 1998. No individual harboured more than one parasite-a whaleworm L3, the ellobiopsid Thalassomyces fagei, a trypanorhynchid (tetrarhynchid) cestode (probably Nybelinia sp.), or a possible rhizocephalan. Controversy regarding the number of moults that occur in the egg of marine ascaridoids is discussed briefly.

Alaska↗