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PubMed2006

Spermiogenesis in the caryophyllidean cestode Khawia armeniaca (Cholodkovski, 1915).

Spermiogenesis of the monozoic cestode Khawia armeniaca (Cholodkovski, 1915), a parasite of Capoeta capoeta sevangi (De Filippi, 1865) (Pisces: Cyprinidae), has been investigated by means of transmission electron microscopy for the first time. The present results show that the type of spermiogenesis in K. armeniaca shares the main features described previously in the pseudophyllideans and/or spathebothriideans: apical dense material in the zone of differentiation in the early stages of spermiogenesis, rotation of flagellum and flagellar bud, proximodistal fusion, and penetration of the nucleus into the spermatid body after the fusion of the free flagellum with the MCP has started. However, only one axoneme and a simple intercentriolar body represent presumably more evolved characters, typical for "higher" tapeworms. Ultrastructural data of spermiogenesis in K. armeniaca may support the hypothesis that the Caryophyllidea are secondarily derived from an ancestor closely allied with the Pseudophyllidea.

Animals↗
PubMed1996

A total DNA characterization in Proteocephalus exiguus and P. percae (Cestoda: Proteocephalidae): random amplified polymorphic DNA and hybridization techniques.

Two morphologically similar fish tapeworms, Proteocephalus exiguus and P. percae, were differentiated by the random amplified polymorphic DNA (RAPD) marker and Southern-blot hybridization techniques. Four geographic isolates of P. exiguus and two of P. percae were studied using eight arbitrary decamer oligonucleotides as primers. Species-specific RAPD fragments enabled reliable separation of the taxa studied. Generally, 1-3 fragments specific for P. percae and 1-4 P. exiguus-specific fragments were detected using individual primers. Intraspecific differences in P. percae depended on the primer used. The profiles generated by the primers OPA 04 and OPA 12 showed an intraspecific variation, whereas six other primers tested revealed indistinguishable banding patterns. On the other hand, intraspecific variability of P. exiguus, detected among four geographic isolates, was evident using all primers. Additionally, the utilization of two species-specific RAPD markers as effective probes was demonstrated. Distinct differences between P. exiguus and P. percae were revealed using each of the restriction enzyme/probe combinations.

Animals↗
PubMed1997

Frequency distributions of fish parasites in the perch Perca fluviatilis L. from Lake Constance.

Seventy perch (Perca fluviatilis) caught in Lake Constance at Langenargen in May 1990 were examined for parasites. The frequency distributions of the eyefluke Diplostomum spathaceum (Rudolphi, 1819), and the tapeworms Proteocephalus percae (Müller, 1780) and Triaenophorus nodulosus (Pallas, 1781) fitted closely to a negative binomial. Only a few fish were highly parasitized. These fishes are devoured by the final hosts: gulls (Diplostomum spathaceum) or the pike (Triaenophorus nodulosus). The fish population was influenced negligibly and the parasite population stayed at a moderate level. During the spawning period female perch were infested with Proteocephalus percae more than the males. This may be because the females had a higher food consumption and became more infected by copepods (intermediate hosts). In contrast, Diplostomum spathaceum, Ichthyocotylurus variegatus, Triaenophorus nodulosus, and Tylodelphys clavata did not occur in different numbers in female and male perches. The frequency distribution of Ichthyocotylurus variegatus (Creplin, 1825) and Tylodelphys clavata (Nordmann, 1832) did not conform to a negative binomial.

Animals↗
PubMed1999

Scolex morphology of the cestode Silurotaenia siluri (Batsch, 1786) (Proteocephalidae: Gangesiinae), a parasite of European wels (Silurus glanis).

The morphology of the scolex of the tapeworm Silurotaenica siluri (Batsch, 1786) (Proteocephalidae: Gangesiinae), a specific parasite of European wels (Silurus glanis L.), was studied using light, scanning (SEM), and transmission electron (TEM) microscopy. The scolex of S. siluri is rather uniform in shape and size; it is globular, and has four prominent, anteriorly directed suckers and a spherical, muscular apical organ corresponding to the rostellum of cyclophyllidean cestodes. The rostellum-like apical organ is armed with five to six irregular rows of small hooklets with a wide, oval basal plate and a short, posteriorly curved blade. The excretory system of the scolex is formed by sinuous secondary canals ending blindly beneath the distal layer of the tegument, not opening outside. The surface of the scolex is covered with filiform microtriches; giant spine-like and blade-like microtriches, incorrectly interpreted as spines or hooklets in previous descriptions of S. siluri, are present on the neck region and posterior margins and internal cavities of the suckers. It is assumed that tegumental spines reported in the scolices of other proteocephalideans (subfamilies Acanthotaeniinae and Gangesiinae, genera Spasskyellina and Nomimoscolex) could indeed be spiniform microtriches.

Animals↗
PubMed1999

Modification of universal 12S rDNA primers for specific amplification of contaminated Taenia spp. (Cestoda) gDNA enabling phylogenetic studies.

The construction of new specific tapeworm primers allowed synthesis of a 311-bp fragment of the mitochondrial 12S rDNA of 11 Taenia species and two Echinococcus species by PCR. After direct sequencing and construction of an alignment, the DNA sequences were calculated by three different phylogenetic algorithms. The phylogenetic trees were tested by 1000 bootstrap replications. Reliability of the nodes was tested by splits testing. All three algorithms revealed a clear monophyletic phylum Taenia, suggesting it may be paraphyletic with respect to the genus Echinococcus. Within the genus Taenia, the first secure group was composed by Taenia saginata, T. solium, T. serialis, T. ovis and T. hydatigena. A delimited second group was formed by T. martis, T. taeniaeformis, T. mustelae and T. parva. All of them were opposed to the genus Echinococcus using other cyclophyllideans as an outgroup. In this study Echinococcus was used as an outgroup, being the closest species against which the ingroup could be routed. The findings of this publication reflect Verster's basic morphologically based grouping of the Taeniidae.

Algorithms↗
PubMed2000

Copulation of Acanthocephalus anguillae (Acanthocephala).

A total of 114 specimens of brown trout, Salmo trutta Linnaeus, 1758, was sampled by electrofishing between October 1998 and July 1999 from the Ceresone stream (North of Padua, Italy). Over 63% of fish were infected with three species of helminth: a tapeworm, Cyathocephalus truncatus (Pallas, 1781), and two acanthocephalan species, Echinorhynchus truttae (Schrank, 1788) and Acanthocephalus anguillae (Muller 1780). On three occasions, in the fore-gut of three brown trout, three pairs of A. anguillae were found in copula. In all three cases, the male's bursa was fully extruded and firmly attached to the posterior region of the female. Cement was found inside the bursa suggesting that insemination had probably occurred. Eight female A. anguillae recovered in five other infected trout had attached copulatory caps.

Acanthocephala↗
PubMed2001

Spermiogenesis in the pseudophyllid cestode Eubothrium crassum (Bloch, 1779).

Spermiogenesis of the pseudophyllidean tapeworm Eubothrium crassum has been described by the aid of transmission electron microscopy for the first time. Initially, early spermatids form a distal cytoplasmic protrusion, a differentiation zone containing a small electron-dense, apically oriented region. Out of this region, two centrioles with rootlets develop. The centrioles become orientated in the same plane with the appearance of an intercentriolar body. Now, the long axes of the rootlets are parallel with each other and with the long axis of the nucleus. Two flagella of subsequently unequal length are formed very rapidly. Simultaneously, a median cytoplasmic process (MCP) develops distal to the flagella. Two arching membranes appear at the base of the differentiation zone. Each flagellum, still being in contact with an intercentriolar body, rotates to a position parallel with the MCP. The nucleus migrates very rapidly into the MCP at this stage. Subsequently, the two flagella fuse with the MCP. Finally, the basal bodies with the rootlets detach from the flagella, the intercentriolar body changes its structure and spermatids are pinched off from a condensing residual cytoplasm at the level of the arching membranes.

Animals↗
PubMed2001

Depolarization of the tegument precedes morphological alterations in Echinococcus granulosus protoscoleces incubated with ivermectin.

The nematocidal activity of ivermectin (IVM) largely arises from its activity as a potent agonist of muscular and neuronal glutamate-gated chloride channels. A cestocidal effect has also been suggested following in vitro treatments, but the molecular basis of this activity is not clear. We studied the effect of IVM on the metacestode stage of the tapeworm Echinococcus granulosus by assessing the viability, ultrastructure, and tegumental membrane potential as a function of drug concentration and incubation time. Concentrations of 0.1 and 1.0 microg/ml of IVM had no effect on any of these three parameters for up to 6 days of treatment. A concentration of 10 microg/ml, however, elicited a sequence of alterations that started with a approximately 20-mV depolarization of the tegumental membrane, and was followed by rostellar disorganization, rigid paralysis and, eventually, loss of viability. It is likely that the IVM-induced depolarization of the tegument acts as the signal that initiates the cascade of degenerative processes that leads to the parasite's death. This would place the tegument as the primary target of action of IVM on cestodes. As an appropriate chemotherapy for the hydatid disease is still lacking, the cestocidal effect of IVM reported here is worth considering.

Animals↗
PubMed2001

Echinococcus multilocularis in European wolves (Canis lupus).

Nested PCR was used as a diagnostic tool to investigate the presence of Echinococcus multilocularis tapeworm in protected species of carnivores in Slovakia. Twenty-three faecal samples from wolves, four samples from bears and three samples from lynx from the Muránska Planina mountains and eight samples from wolves from the Bukovské Vrchy mountains were examined. E. multilocularis DNA was detected in two samples of wolves' faeces from the Muránska Planina mountains and one sample from the Bukovské Vrchy mountains. Examination of bears' and lynx faecal samples gave negative results. The detection of E. multilocularis in wolves has extended the range of its known definitive hosts in Europe.

Animals↗
PubMed2003

The embryonic development of the bodywall and nervous system of the cestode flatworm Hymenolepis diminuta.

Cestodes (tapeworms) are a derived, parasitic clade of the phylum Platyhelminthes (flatworms). The cestode body wall represents an adaptation to its endoparasitic lifestyle. The epidermis forms a non-ciliated syncytium, and both muscular and nervous system are reduced. Morphological differences between cestodes and free-living flatworms become apparent already during early embryogenesis. Cestodes have a complex life cycle that begins with an infectious larva, called the oncosphere. In regard to cell number, cestode oncospheres are among the simplest multicellular organisms, containing in the order of 50-100 cells. As part of our continuing effort to analyze embryonic development in flatworms, we describe here the staining pattern obtained with acTub in embryos and larvae of the cestode Hymenolepis diminuta and, briefly, the monogenean Neoheterocotyle rhinobatidis. In addition, we labeled the embryonic musculature of Hymenolepis with phalloidin. In Hymenolepis embryos, two different cell types that we interpret as neurons and epidermal gland cells express acTub. There exist only two neurons that develop close to the midline at the anterior pole of the embryo. The axons of these two neurons project posteriorly into the center of the oncosphere, where they innervate the complex of muscles that is attached to the hooklets. In addition to neurons, acTub labels a small and invariant set of epidermal gland cells that develop at superficial positions, anteriorly adjacent to the neurons, in the dorsal midline, and around the posteriorly located hooklets. During late stages of embryogenesis they spread and form a complete covering of the embryo. We discuss these data in the broader context of platyhelminth embryology.

Animals↗
PubMed1998

The distribution of F-actin during the development of Diphyllobothrium dendriticum (Cestoda).

The distribution of actin filaments in all developmental stages of the tapeworm Diphyllobothrium dendriticum was studied. It is the first investigation of the placement of microfilaments during the development of a flatworm, and the results show that actin filaments, in all developmental stages, can be found in the subtegument and the flame cells. Muscle fibers possibly corresponding to the longitudinal, transversal, and dorsoventral muscles of the adult and plerocercoid were already detected in the procercoid. Concerning the adult worm, a new set of longitudinal fibers in the peripheral parts of the adult proglottid was found. The ducts of the protonephridial system and the vitellarias were seen to be surrounded by longitudinally oriented actin filaments, while the uterine ducts and the vagina were encircled by microfilaments. Prominent layers of circular muscle fibers surrounded the cirrus and the seminal vesicle, and radial fibers were also detected. Areas faintly stained with TRITC-phalloidin were found in the developing germ cells, the cells of the genital anlage, vitelline cells, the tegument, and the main nerve cords. None of these structures were autofluorescent, which is also true concerning the intensively labeled oncospheral hooks.

Actins↗
PubMed2004

The distribution of Echinococcus granulosus in moose: evidence for parasite-induced vulnerability to predation by wolves?

The role of parasites in influencing the trophic dynamics of hosts is becoming increasingly recognized in the ecological literature. Echinococcus granulosus is a tapeworm that relies on the predator-prey relationship between the definitive host (wolf, Canis lupus) and the intermediate host, (moose, Alces alces) to complete its life cycle. Heavy infection by E. granulosus may predispose moose to increased risk of predation by wolves. Theory predicts that parasite-induced vulnerability to predation will reduce the degree of aggregation of parasites in a host population. We tested for different levels of aggregation of E. granulosus in moose in areas of low, moderate, and high levels of wolf predation using Green's coefficient of dispersion. Parasite aggregation was lower in an area with high predation rate, thus we hypothesize that heavy infection by E. granulosus predisposes moose to predation by wolves. This increase in predation rate due to parasite infection may influence the role of wolves in regulating moose populations. We discuss alternative explanations for the negative correlation between predation rate and parasite aggregation.

Age Factors↗
PubMed2005

Control of scavenger receptor-mediated endocytosis by novel ligands of different length.

The scavenger receptor recognized as a multiligand family of receptors falls in the group that is internalised through endocytosis. In this report we used several recombinant fragments of the tapeworm protein paramyosin, known to form filamentous dimers that bind collagenous structures as ligands of different length for the class A type I scavenger receptor (SR-AI). While native CHO cells are unresponsive to any of the recombinant fragments, it is shown that CHO cells transfected with this receptor efficiently internalise recombinant fragments that correspond to two thirds of the full-length paramyosin. In contrast, recombinant products corresponding to one-third of the full-length paramyiosin are not internalised. It is also shown that important molecules in the organization of the coated pit, are enriched when the two-thirds long paramyosin fragments were bound and internalised through the SR-AI. Moreover, internalisation of these fragments trigger a classical apoptotic pathway shown by the presence of TUNEL positive cells and the appearance of apoptotic bodies. We report paramyosin as a new ligand for the scavenger receptor and provide evidence supporting the notion that these receptors upon the formation of arrays with length-specific molecules, not only trigger endocytosis but also seem to regulate the synthesis of molecules involved in the organization of coated pits.

Animals↗
PubMed2005

Clestobothrium gibsoni n. sp. (Cestoda: Bothriocephalidae) from the bullseye grenadier Bathygadus macrops Goode & Bean (Macrouridae) in the Gulf of Mexico.

Clestobothrium gibsoni n. sp. is described from the intestine of the bullseye grenadier Bathygadus macrops (Macrouridae) collected in the northeastern Gulf of Mexico. The new species can be distinguished from both C. crassiceps (Rudolphi, 1819), the type-species of the genus, and C. neglectum (Lönnberg, 1893), the second species in the genus, by its unique ovary, which is transversely elongate and tapered on both ends rather than being U-or H-shaped, and by having more testes (60-65 vs 40-50 and 35-45 per proglottid). The new species is also compared to Bothriocephalus acheilognathi Yamaguti, 1934 and B. kivuensis Baer & Fain, 1954, two species with similar scoleces which have previously been assigned to Clestobothrium . The generic diagnosis of Clestobothrium is amended to include species with either anoperculate or operculate eggs. This is the first report of an adult tapeworm from a species of Bathygadus , and the first report of a species of Clestobothrium Lühe, 1899 (Bothriocephalidae) from the Gulf of Mexico.

Animals↗
PubMed2005

Aploparaksis kornyushini n. sp. (Cestoda: Hymenolepididae), a parasite of the woodcock Scolopax rusticola (L.), and its life-cycle.

Aploparaksis kornyushini n. sp. is described from a woodcock Scolopax rusticola L. from Lithuania, Russia (Tver' Region) and the Ukraine. Initially, one specimen of this tapeworm was described and figured by Kornyushin (1975) as A. scolopacis Yamaguti, 1935 together with another specimens belonging to the latter species. A. kornyushini n. sp. and A. scolopacis are morphologically very similar species. They can be distinguished by the slightly different length of the rostellar hooks and by the shape of the cirrus, which lacks basal bulbus in the new species. A. kornyushini can be readily distinguished from the remaining species of Aploparaksis Clerc, 1903 from woodcocks by the structure of its fully-developed embryophore, which has polar thickenings and two large or a few smaller lateral projection; this combination of characters is unknown for embryophores other Aploparaksis spp. (except for A. scolopacis). The life-cycle of A. kornyushini was studied under experimental conditions in Lithuania. The metacestodes were located under the chlorogogenous tissue of the intestine of Dendrobaena octaedra (Lumbricidae). The metacestode exhibits a pattern of postembryonal development typical for the cysticercoid modification termed an 'ovoid diplocyst'.

Animals↗
PubMed2006

A new species of Aberrapex Jensen, 2001 (Cestoda: Lecanicephalidea) from Taeniura lymma (Forsskål) (Myliobatiformes: Dasyatidae) from off Sabah, Malaysia.

A new lecanicephalidean species of Aberrapex Jensen, 2001 is described from the blue-spotted fantail ray Taeniura lymma (Forsskål) collected off the eastern coast of Sabah in Malaysian Borneo. This is the first record of a lecanicephalidean tapeworm from the island of Borneo and the first record of Aberrapex from this host species. A. manjajiae n. sp. is easily distinguished from its two congeners, A. senticosus Jensen, 2001 and A. arrhynchum (Brooks, Mayes & Thorson, 1981) Jensen, 2001, based on its overall smaller size (928-1,971 vs 1,485-6,333 and up to 3,350 microm long, respectively) and fewer testes (10-19 vs 20-40 and 18-25, respectively). In addition, A. manjajiae n. sp. is readily distinguished from A. senticosus based on a more anteriorly positioned genital pore (76-85 vs 52-72% of proglottid length from posterior end) and its distal bothridial microthrix pattern. A. manjajiae n. sp. can be further distinguished from A. arrhynchum based on its smaller scolex (82-101 x 119-164 vs 177-186 x 233-326 microm). The host distribution of Aberrapex is expanded from the Myliobatidae to include the Dasyatidae.

Animals↗
PubMed2004

Helminthic infections of the liver.

Human helminthic infestation is exceedingly common on a global scale, with as many as 1.5 to 2 billion people affected worldwide. Helminths (parasitic worms) that infect the liver and hepatobiliary system include nematodes (roundworms), cestodes (tapeworms), and trematodes (flatworms or flukes). The majority of morbidity and mortality from these infestations is caused by the host immune response to the larvae or adult worm. Helminthic disease manifestations vary from the extremes of asymptomatic carriage to cirrhosis and decompensated liver disease. Current basic science and clinical research focus on improvements in medical therapy, mass screening and chemoprophylaxis, and the development of preventative vaccine strategies.

Helminthiasis↗
PubMed2005

Helminthic Infections of the Liver.

Human helminthic infestation is exceedingly common on a global scale, with as many as 1.5 to 2 billion people affected worldwide. Helminths (parasitic worms) that infect the liver and hepatobiliary system include nematodes (roundworms), cestodes (tapeworms), and trematodes (flatworms or flukes). The majority of morbidity and mortality from these infestations is caused by the host immune response to the larvae or adult worm. Helminthic disease manifestations vary from the extremes of asymptomatic carriage to cirrhosis and decompensated liver disease. Current basic science and clinical research focus on improvements in medical therapy, mass screening and chemoprophylaxis, and the development of preventative vaccine strategies.

Journal Article↗