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ABSTRACT: Monobothrium wageneri is a monozoic caryophyllidean tapeworm of tench Tinca tinca. The pathological changes caused by this parasite within the intestinal tract of wild tench are described for the first time. Parasites were found attached to the anterior third of the intestine in tight clusters comprising up to 109 tapeworms. Infection was associated with the formation of raised inflammatory swellings surrounding the parasites. This host response, combined with the deep penetration of the scolex into the gut wall, formed a very firm seat of parasite attachment. Histopathological changes were characterised by a pronounced fibrogranulomatous lesion that extended through all layers of the intestine. This was accompanied by haemorrhage, oedema, necrosis and degeneration of the muscularis. A marked eosinophilic interface layer between the scolex of the tapeworm and gut wall indicated intimate host-parasite contact. Ultrastructural examinations revealed coniform spinitriches covering the neck and lateral sides of the scolex and capilliform filitriches present on the apical end of the scolex. Numerous glandular cytons (tegumental glands) were recorded throughout the scolex tegument. Large numbers of secretory granules discharged from the glands through a network of processes onto the scolex surface were consistent with distancing the cellular responses of the host. Observations of severe inflammatory lesions, partial intestinal occlusion and the potential for intestinal perforation represent important pathological changes that are consistent with loss of normal gut function. The lesions associated with the attachment of M. wageneri are more severe than those recorded for any other tapeworm of British freshwater fish.
Diseases of Aquatic Organisms 12/2011; 97(2):143-54. · 2.20 Impact Factor
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ABSTRACT: Larvae of the cyclophyllidean tapeworms Paradilepis scolecina (Rudolphi, 1819), Neogryporhynchus cheilancristrotus (Wedl, 1855) and Valipora campylancristrota (Wedl, 1855), are described from British freshwater fish. The morphometrics of the rostellar hooks, infection characteristics and host ranges of these parasites from fisheries in England and Wales are presented. Difficulties in the detection, handling and identification of these tapeworms are highlighted, and may in part explain the paucity of records from Britain. Tissue digestion was shown to be a useful technique for the examination of these parasites, providing clear and consistent preparations of the rostellar hooks for measurement. The pathological changes caused by P. scolecina to the liver of wild tench, Tinca tinca, are detailed for the first time. Tapeworms located in the hepatic parenchyma and pancreatic tissues caused little pathological damage and invoked only mild inflammatory responses. The small size of these tapeworms and their encapsulation within host tissues appear to limit the severity of pathology, compared with parasites that insert their rostellum during attachment.
Journal of Helminthology 01/2011; 86(1):1-9. · 1.38 Impact Factor
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ABSTRACT: Organisms with wide geographical or phenotypic diversity often constitute assemblages of genetically distinct species or lineages. Within parasites, an emergence of host-specific lineages is assumed to create such cryptic variability; however, empirical evaluation of these processes is scarce. Here, we analyse populations of a parasite with a complex life cycle, wide host spectrum and global distribution, with the aim to reveal factors underlying the evolution of host- or geography-dependent lineages. Using 15 microsatellite loci, deep genetic distances were observed between populations from distant geographical areas. On the local scale, host-mediated genetic structure was found among sympatric samples. Two lineages differing in the spectrum of infected hosts co-occurred in the Euro-Mediterranean area, and two distinct lineages were recovered from Lake Tana in Ethiopia. Although sampled across several host taxa and multiple localities, a lack of marked genetic structure was seen in the populations belonging to one of the European lineages. Only weak genetic differentiation between sympatric samples from two host species was found. Complexity of the parasite life-cycle contributed to such a stratified pattern. Differences in the immune response between fish hosts were suggested as the factor diversifying the populations locally; conversely, high mobility of the parasite due to migration with its bird (definitive) host were assessed to homogenize populations across the area of distribution. However, despite the high mobility, large bodies of salt water prevent the parasite from long-distance migrations, as was demonstrated in an example of the Mediterranean Sea which represented an effective barrier to gene flow.
Molecular Ecology 03/2009; 18(6):1187-206. · 5.52 Impact Factor
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ABSTRACT: Pseudophyllidea van Beneden in Carus, 1863, a well recognised order of tapeworms (Platyhelminthes: Eucestoda), is suppressed because it is composed of two phylogenetically unrelated groups, for which the new names Bothriocephalidea and Diphyllobothriidea are proposed. The new orders differ from each other in the following characters: (i) position of the genital pore: on the dorsal, dorso-lateral or lateral aspects and posterior to the ventral uterine pore in the Bothriocephalidea versus on the ventral aspect of segments and anterior to the uterine pore in the Diphyllobothriidea; (ii) the presence of a muscular external seminal vesicle in the Diphyllobothriidea, which is absent in the Bothriocephalidea; (iii) the presence of a uterine sac in the Bothriocephalidea, which is absent in the Diphyllobothriidea; and (iv) the spectrum of definitive hosts: mainly teleost fishes, never homoiothermic vertebrates in the Bothriocephalidea, versus tetrapods, most frequently mammals, in the Diphyllobothriidea, with species of Diphyllobothrium, Spirometra and Diplogonoporus parasitic in humans. The Diphyllobothriidea, which includes 17 genera in four families (Digramma is synonymised with Ligula), is associated with cestode groups that have a range of plesiomorphic characters (Haplobothriidea and Caryophyllidea), whereas the Bothriocephalidea, consisting of 41 genera grouped in four families, is the sister-group to the 'acetabulate' or 'tetrafossate' cestodes, which are generally regarded as having derived characters.
International Journal for Parasitology 02/2008; 38(1):49-55. · 3.39 Impact Factor
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ABSTRACT: A review of heterophyid trematodes found in Mexico, both as metacercariae encysted in ® sh and adults in ® sh-eating birds and mammals, is presented, including numerous new geographical and host records. Data on the morphology, spectrum of intermediate and de® nitive hosts, site of infection of metacercariae, distribution in Mexico and biology of the following species are provided (species ® rst reported from Mexico marked with an asterisk): *Ascocotyle (Ascocotyle) gemina Font, Overstreet and Heard, 1984; A. (A.) leighi Burton, 1956; A. (A.) tenuicollis Price, 1935; A. (Leighia) chandleri Lumsden, 1963; *A. (L .) mcintoshi Price, 1936; A. (L .) megalocephala Price, 1932; A. (L .) nunezae Scholz, Vargas-Va zquez, Vidal-Martõ  nez and Aguirre-Macedo, 1997; Ascocotyle (Leighia) sp.; *A. (Phagicola) ampullacea Miller and Harkema, 1962; A. (P.) diminuta Stunkard and Haviland, 1924; A. (P.) macrostoma (Robinson, 1956); *A. (P.) longa Ransom, 1920; A. (P.) nana Ransom, 1920; Centrocestus formosanus (Nishigori, 1924); *Euhaplorchis californiensis Martin, 1950; Galactosomum pu ni Yamaguti, 1941; *Haplorchis pumilio (Looss, 1896); Heterophyidae gen. sp. (5 Haplorchoides sp. of Scholz and Vargas-Va zquez, 1998); *Phocitremoides ovale Martin, 1950; and *Pygidiopsis pindoramensis (Travassos, 1929). Two of the above-listed species, C. formosanus and H. pumilio, have been introduced recently to Mexico, most probably from Asia with the imported thiarid snail Melanoides tuberculata (Mu È ller). Metacercariae of heterophyid trematodes are among the most frequent and abundant parasites of ® sh in Mexico, in particular in its southeastern part.
Journal of Natural History. 01/2008; 35:1733-1772.
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ABSTRACT: Recent studies have demonstrated the invalidity of the Pseudophyllidea, a long-term recognised order of tapeworms (Platyhelminthes: Cestoda), typical in possessing two dorsoventrally situated attachment organs called bothria. In fact, cestodes parasitic in tetrapods, especially mammals including man, form a relatively basal group called provisionally the "Diphyllobothriidea", whereas tapeworms occurring in freshwater and marine fish, with a few taxa known from amphibians (frogs and newts), belong to a more derived clade, for which the name "Bothriocephalidea" is tentatively proposed. Revision of the "Bothriocephalidea", based on literary data, study of type- and voucher specimens and extensive newly collected material made it possible to critically review the species composition of the group and to prepare a tentative list of its valid species. Out of 305 nominal taxa, only 125 species are considered to be valid. In addition, the spectrum of definitive hosts and geographical distribution of bothriocephalideans are briefly discussed.
Parassitologia 10/2007; 49(3):129-46.
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ABSTRACT: Phylogenetic relationships of cestodes of the order Pseudophyllidea (Platyhelminthes: Cestoda) were examined using sequences of complete small subunit and partial (D1-D3 region) large subunit nuclear rDNA of members of all pseudophyllidean families. The results provide evidence of paraphyly of the order as indicated by previous molecular phylogenetic analyses based on a much lower number of species sequenced. Pseudophyllidean tapeworms represent an artificial assemblage comprising two unrelated clades. "Bothriocephalidea" is formed by four families sensu Bray et al. (1994), namely Bothriocephalidae, Echinophallidae, Philobythiidae and Triaenophoridae, whereas two other families, Diphyllobothriidae and Cephalochlamydidae, give rise to the "Diphyllobothriidea". The present results indicate that "Bothriocephalidea" forms the most derived clade of all difossate and tetrafossate/bothriate tapeworm lineages which are considered to be basal relative to the rest of tetrafossate/bothridiate and acetabulate cestodes. By contrast, "Diphyllobothriidea", which includes medically important parasites (Diphyllobothrium and Spirometra), appeared more basal, without a clearly resolved position within other difossate tapeworm lineages.
International Journal for Parasitology 01/2007; 36(14):1535-41. · 3.39 Impact Factor
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ABSTRACT: Four species of the genus Eubothrium (E. crassum, E. fragile, E. rugosum and E. salvelini) were subjected to morphometric comparison. Discriminant analysis was conducted utilising 17 characters measured on the scolex and strobila of 101 specimens. Univariate statistics were first used to detect features that were useful for separating individual Eubothrium species and two different host populations of E. salvelini. Subsequent multivariate discriminant analysis, combining all the measured variables, made it possible to separate all four species. A comparison of the four taxa revealed that (1) E. fragile is the most distinct species, possessing a much smaller scolex than the other congeners, and its similarity with the other marine species E. crassum is not proven; (2) the two freshwater taxa, E. rugosum and E. salvelini are the most similar; (3) the characters most suitable for species differentiation are the length of the scolex, the width of the apical disc, the width of the neck and its area, the width of eggs and the number of testes; (4) the width of the apical disc was confirmed to be the most stable character at the intraspecific level (within E. salvelini host populations) and is therefore considered to be a trait of the highest discriminative power in the subset of four Eubothrium species.
Parasitology International 10/2005; 54(3):207-14. · 2.13 Impact Factor
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ABSTRACT: Spermiogenesis of Corallobothrium solidum Fritsch 1886, has been investigated by transmission electron microscopy. The zone of differentiation contains the two centrioles, each with one thin root, being orientated in the same plane only when a single intercentriolar body (ICB) appears between them. A median cytoplasmic process (MCP) develops distally to the two flagella, which are of unequal length, get longer and rotate towards the MCP. The nucleus penetrates into the spermatid body after the fusion of both flagella with the MCP has started. Flagellar roots occur occasionally in some spermatids. New for the Eucestoda are the following findings: 1. cortical microtubules (CMs) are arranged in two short parallel rows in one-axoneme region of some spermatids; 2. the crested body of spermatid consists either of electron-dense tubular elements and interposes itself between CMs, or it is rather homogeneous and situated more peripherally above one continuous semicircle of CMs. The present results support previous data that the type of spermiogenesis in proteocephalideans resembles mostly that observed in tetraphyllideans (Onchobothriidae and Phyllobothriidae), thus supporting the view of a close phylogenetic relationship of tetraphyllidean and proteocephalidean cestodes.
Acta Zoologica 04/2005; 86(1):55 - 61. · 1.13 Impact Factor
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ABSTRACT: In a manner similar to many other groups of organisms, the tapeworm order Proteocephalidea poses a difficult phylogenetic problem if treated on the basis of single-gene analysis. Since the biogeography and host distribution of proteocephalideans make these tapeworms a potentially interesting model for evolutionary and co-evolutionary studies, we tried to resolve their phylogenetic relationships by applying a multi-gene approach. The ITS2 sequences and V4 hypervariable loop of 18S rRNA were obtained for 43 and 35 proteocephalidean taxa, respectively, and combined with other sequences available in the GenBank. The phylogenetic analysis of the combined DNA set was confronted with characters derived from ITS2 secondary structures. Using this approach, a species-rich Neotropical lineage of proteocephalideans could be reliably resolved. The phylogenetic relationships within this group show a high degree of phylogeny-independent host distribution. The reconstruction of ITS2 secondary structure revealed a universal 4-domain arrangement, which is conserved across a wide range of Neodermata. Several motifs of the secondary structure could be mapped to the phylogenetic tree as possible clade synapomorphies.
Parasitology 04/2005; 130(Pt 3):359-71. · 2.96 Impact Factor
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ABSTRACT: The presence of immature stages of Proteocephalus macrocephalus in nine-spined stickleback Pungitius pungitius, four-spined stickleback Apeltes quadracus, three-spined stickleback Gasterosteus aculeatus, and mummichog Fundulus heteroclitus from Sable Island ponds was confirmed using scolex morphology. The occurrence of this eel-specific parasite in these accidental hosts provides evidence for recent visits by eels Anguilla rostrata to the isolated island in the North-west Atlantic Ocean off the east coast of Canada.
Journal of Fish Biology 03/2005; 54(3):685 - 687. · 1.68 Impact Factor
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ABSTRACT: The caryophyllidean tapeworm Atractolytocestus huronensis Anthony, 1958, originally described from the common carp Cyprinus carpio carpio L. from North America, has recently been introduced into Europe (UK, Hungary). In the present study, the dispersion of the tapeworm in other countries of Central Europe (Slovakia and the Czech Republic) is described, including its first observation in the common carp of the Tisa River, southeastern Slovakia. Because of the transboundary location of the river, there are possible consequences of the rapid distribution of the parasite to other regions throughout the Danube River basin. The parasite has also been found in cultured carp from fishponds in South Bohemia, from where the carp are imported to many European countries. Rapid dissemination of this cestode in Europe indicates its ability to colonise new regions, and represents another example of man-made introduction of potential pathogens of carp and other farmed fish. The morphology of the A. huronensis specimens found is compared with that of specimens from Hungary and North America as well as that of Atractolytocestus sagittatus (Kulakovskaya and Akhmerov, 1965) from the same fish host in eastern Asia.
Diseases of Aquatic Organisms 12/2004; 62(1-2):115-9. · 2.20 Impact Factor
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ABSTRACT: Phylogenetic analysis of sequences of the ITS-2 rRNA genes of 20 samples of pseudophyllidean cestodes of the family Diphyllobothriidae (Ligula, Digramma, Diphyllobothrium, and Schistocephalus) from different hosts and geographical regions revealed that: (1) the inclusion of ligulids (previously family Ligulidae) to the Diphyllobothriidae is correct; (2) Schistocephalus appears as the most basal taxon of the Diphyllobothriidae, well separated from Ligula and Digramma, thus supporting the validity of Schistocephalinae Dubinina, 1962; (3) Digramma belonged with samples of Ligula, thus suggesting its invalidity as a genus; and (4) isolates of Ligula, presumably belonging to Ligula intestinalis, are paraphyletic, indicating that this species may represent a complex of separate taxa. Our results indicate the necessity for a taxonomic revision of the family Diphyllobothriidae.
Parasitology Research 10/2004; 94(1):10-5. · 2.15 Impact Factor
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ABSTRACT: A morphological evaluation and genetic analysis (sequencing of ITS2 region of rDNA) of proteocephalidean cestodes from rainbow smelt (Osmerus mordax) in the Saint Lawrence Estuary, Canada, has shown their conspecificity with Proteocephalus tetrastomus, a specific parasite of smelt (Osmeridae), previously known only from northern Europe, Russia, and Japan. The parasite occurs only in larval, but not adult, smelt in the Saint Lawrence Estuary. Prevalence of larval smelt infection was 42% (n = 50), mean intensity 2.1 +/- 2.4 and mean abundance 1.1 +/- 1.0.
Journal of Parasitology 05/2004; 90(2):425-7. · 1.40 Impact Factor
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ABSTRACT: A total of 55 domestic cats (Felis catus f. domestica) and one wild (Bengal) cat (Prionaluirus bengalensis) from the Vientiane Province, central Laos, were examined for helminth parasites with emphasis given to potential human parasites. The following species were found (parasites infective to man marked with an asterisk): Opisthorchis viverrini, Haplorchis pumilio, H. taichui, H. yokogawai, Stellantchasmus falcatus (Digenea); Spirometra sp., Dipylidium caninum, Taenia taeniaeformis (Cestoda); Capillariidae gen. sp., Toxocara canis, T. cali, Ancylostoma ceylanicum, A. tubaeforme, Gnathostoma spinigerum, Physaloptera preputialis (Nematoda); and Oncicola sp. (Acanthocephala). This study demonstrated that examination of cats may provide useful data on the occurrence of helminths which are potential causative agents of human diseases.
Parasite (Paris, France) 01/2004; 10(4):343-50. · 1.00 Impact Factor
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ABSTRACT: The host specificity and distribution of Eubothrium crassum (Bloch, 1779) and Eubothrium salvelini (Schrank, 1790), morphologically fairly similar pseudophyllidean tapeworms parasitizing salmonid fish, were critically assessed on the basis of morphological and genetic evaluation of extensive material collected from different definitive hosts and geographical regions in Europe. Eubothrium crassum occurs in fish of the genera Salmo, i.e. salmon (S. salar - both freshwater and marine), sea trout (S. trutta trutta), brown trout (S. trutta fario), and lake trout (S. trutta lacustris), and also in Danubian salmon (Hucho hucho) and vendace (Coregonus albula). Eubothrium salvelini parasitizes Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) in Europe, and also whitefish (Coregonus wartmanni). Rainbow trout (Oncorhynchus mykiss), which is not a native European fish species, was found to be a suitable definitive host for both Eubothrium species, which may occur simultaneously in the same fish. Previous records of E. crassum in Arctic char and brook trout, and those of E. salvelini in fish of the genus Salmo were most probably misidentifications. Most studies of Eubothrium have involved salmonids from the northern part of Europe, with few records from southern and south-eastern Europe. This study also confirmed the reliability of the morphology of the apical disc for the discrimination of E. crassum and E. salvelini.
Journal of Helminthology 10/2003; 77(3):255-62. · 1.38 Impact Factor
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ABSTRACT: Spermiogenesis of the proteocephalidean cestode Proteocephalus torulosus (Batsch, 1786) was examined for the first time using transmission electron microscopy. Spermiogenesis begins with the formation of a distal cytoplasmic protrusion, a differentiation zone, at the periphery of the early spermatid. This differentiation zone is lined with cortical microtubules and contains two centrioles aligned along the same axis. Subsequently, each centriole is associated with the striated root and the intercentriolar body appears between them. A flagellar bud arises from each centriole, growing later as a free flagellum. Simultaneously, a median cytoplasmic process (MCP) develops distally to the flagella. The two flagella, which are of unequal length, become longer and rotate towards the MCP. At this stage, two arching membranes appear at the base of the differentiation zone. The nucleus elongates and when both flagella are fused with the MCP, the nucleus subsequently migrates into the MCP. Finally, the advanced spermatids detach from a condensing residual cytoplasm at the level of the arching membranes.
Parasitology Research 08/2003; 90(4):318-24. · 2.15 Impact Factor
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ABSTRACT: 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.
Parasitology Research 05/2003; 89(6):473-9. · 2.15 Impact Factor
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ABSTRACT: The fine structure of the mature spermatozoon of the proteocephalidean tapeworm Proteocephalus torulosus, a parasite of cyprinid fishes, was studied by transmission electron microscopy for the first time. The mature spermatozoon of P. torulosus is filiform and tapered at both extremities. It contains two axonemes of the 9+"1" type and of unequal length. The anterior extremity of the spermatozoon bears a helicoidal crested body approximately 100 nm thick. Cortical microtubules of two types lie parallel to the spermatozoon axis. The nucleus is a fine cord of condensed chromatin. The slightly electron-dense cytoplasm contains electron-dense granules in regions II and III of the spermatozoon. The anterior and posterior extremities of the spermatozoon contain a single axoneme. The mature spermatozoon of P. torulosus differs from that of other Proteocephalusspecies in the presence of a single crested body and in the morphology of its posterior end.
Parasitology Research 04/2003; 89(5):345-51. · 2.15 Impact Factor
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ABSTRACT: 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.
Parasitology Research 01/2003; 89(6):473-479. · 2.15 Impact Factor
