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PubMed2005

Molecular phylogeny and systematics of anoplocephaline cestodes in rodents and lagomorphs.

A molecular phylogenetic hypothesis is presented for the anoplocephaline cestodes of placental mammals based on sequence data from the mitochondrial cytochrome c oxidase I (COI) gene, the nuclear-encoded 28S rRNA gene and the internal transcribed spacer region I of rRNA (ITS1). The material consists of 35 species representing nine genera of cestodes, with emphasis on taxa parasitising rodents and lagomorphs in the Holarctic region. The resulting phylogenies show considerable disagreement with earlier systematic and phylogenetic hypotheses derived from morphology. Specifically, the results contradict the view of uterine morphology being the primary determinant of deeper phylogenetic splits within Anoplocephalinae. Also, the role of genital duplication as a means of generic divergence was not found to follow consistently the pattern suggested by earlier hypotheses. Colonisation of novel host lineages has evidently been the predominant mode of diversification in anoplocephaline cestodes of placental mammals; evidence for phyletic co-evolution was obscure. The phylogenies consistently distinguished a large monophyletic group including all species from arvicoline rodents (voles and lemmings), primarily representing the genera Anoplocephaloides Baer, 1923 and Paranoplocephala Lühe, 1910. Phylogenetic relationships within the "arvicoline clade" of cestodes were generally poorly resolved. Consistent support for nodes above and below the unresolved polytomy indicates a rapid radiation involving a nearly simultaneous diversification of many lineages, a scenario also proposed for the arvicoline hosts.

Animals↗
PubMed2006

Cestode systematics and phylogeny move forward.

This paper represents a meeting report for the Fifth International Workshop on Cestode Systematics and Phylogeny held at the Institute of Parasitology, Academy of Sciences of the Czech Republic, Ceské Budejovice, 18-22 July 2005. The major topics discussed included (i) the progress in cestode systematics during 2002-2005, (ii) the use of the life-cycle data in phylogenetic studies, (iii) the utilisation of new morphological and molecular characters in cestode systematics and phylogeny, and (iv) the ongoing work on the completion of the Global Cestode Database.

Animals↗
PubMed2000

Vitellocytes and vitellogenesis in cestodes in relation to embryonic development, egg production and life cycle.

Vitellocytes have two important functions in cestode embryogenesis: (1) formation of hard egg-shell (e.g. Pseudophyllidea) or a delicate capsule (e.g. Cyclophyllidea), and (2) supplying nutritive reserves for the developing embryos. During evolution any of these two functions can be reduced or intensified in different taxa depending on the type of their embryonic development, degree of ovoviviparity and life cycles. Within the Cestoda, there are three monozoic taxa with only one set of genital organs: Amphilinidea, Gyrocotylidea and Caryophyllidea. In these monozoic taxa and some polyzoic groups with well developed vitellaria (e.g. Pseudophyllidea, Trypanorhyncha) a single oocyte [=germocyte] and a large number of vitellocytes (up to 30) are enclosed within a thick, hardened egg-shell, forming a type of eggs typical for the basic pattern of Neodermata. Only one type of egg-shell enclosures, the so-called 'heterogeneous shell-globule vesicle' is common for the above mentioned cestode taxa. Each membrane-bounded vesicle of mature vitellocytes contains numerous electron-dense shell globules embedded in a translucent matrix. In free-living Neoophora and Monogenea there are two types of vesicles with dense granules; the second is considered to be proteinaceous reserve material. Within the Cestoda, the numbers of vitellocytes per germocyte are reduced in those taxa forming eggs of the 'Cyclophyllidean-type' (e.g. Cyclophyllidea, Tetraphyllidea, Pseudophyllidea). This is particularly evident in Cyclophyllidea; for example, in vitellocytes of Hymenolepis diminuta (Hymenolepididae) there are numerous vitelline granules of homogeneously electron-dense material; in Catenotaenia pusilla (Catenotaeniidae) there are three large, homogenous vitelline vesicles, while in Inermicapsifer madagascariensis (Anoplocephalidae) there is only one large vitelline vesicle, containing homogeneously electron-dense material, which occupies most of the vitelline cell volume. In this respect the Tetraphyllidea and Proteocephalidea, in forming eggs that lack a hard egg-shell, hold an intermediate position. A comparison of interrelationships which exist among types of vitellocytes, vitellogenesis, types of embryonic development, ovoviviparity and life cycles indicates parallelisms and analogies in adaptation to the parasitic way of life in different groups of cestodes. Knowledge on cestode vitellogenesis may also have an important applied aspect. Vitellocytes, due to their high metabolic rate, represent a very sensitive target for analysing effect of anthelminthic drugs upon the egg formation (ovicidal effects); rapid degeneration of vitellocytes is usually accompanied by a cessation of egg production.

Animals↗
PubMed1993

Vaccination against cestode parasites.

Cestodes are tapeworm parasites. Infection in the intermediate host with larval (metacestode) parasites causes medically and economically important diseases known as hydatidosis and cysticercosis. Immunization against experimental infection with metacestode parasites has been highly successful, in marked contrast with the relative ineffectiveness of vaccines against infection with most parasitic organisms. High levels of immunity against a challenge infection with taeniid cestode eggs can be stimulated by immunization with extracts of the parasites, particularly with extracts of the oncosphere life-cycle stage. This led to the production of a recombinant antigen vaccine against infection in sheep with the parasite Taenia ovis, the first highly effective, non-living vaccine against a parasitic infection in animals or humans. This paper reviews immunity to the adult and metacestode life-cycle stages of cestode parasites, development and application of the T. ovis vaccine, and prospects for vaccines against other cestode infections.

Animals↗
PubMedDate not supplied

[The symbiotic microflora associated with the tegument of proteocephalidean cestodes and the intestines of their fish hosts].

The indigenous symbiotic microflora associated with the tegument of proteocephalidean cestodes and the intestines of their fish hosts has been investigated in morphological and ecological aspects. The indigenous microflora associated with the cestode tegument consists of the nannobacteria population, which was present obligatorily on the surface of tegument, and the "deep microflora". The deep microflora associates with some few species of parasites only. Each individual host-parasite micro-biocenosis includes specific indigenous symbiotic microorganisms, with the differing microfloras of host intestine and parasite. Physiology, biochemistry and/or diet of hosts apparently influence on the symbiotic microflora's structure of parasites. The least bacteria abundance and diversity of their morphotypes were observed in the parasites from baby fishes. The diversity and abundance of bacteria were increased with the fish host ageing and the formation of the definitive structure of its intestine. It is an evidence of the gradual invading of the intestinal parasites (cestodes) tegument by bacterial cells. The invading is realized on the base of the microflora that was present in the food of fish host. The symbiotic microflora has specific morphological features, can regulate the homeostasis of the cestodes and fish hosts and also can maintain equilibrium of alimentary and immune interrelations in the host-parasite system.

Animals↗
PubMed1984

Comparison of cestode antigens in an enzyme-linked immunosorbent assay for the diagnosis of Echinococcus granulosus, Taenia hydatigena and T ovis infections in sheep.

Nine antigens, prepared from somatic tissue, cyst fluids or produced during in vitro culture of Echinococcus granulosus, Taenia hydatigena, T ovis or T crassiceps were tested for their suitability for the diagnosis of larval cestode infections in sheep by the enzyme-linked immunosorbent assay (ELISA). The sensitivity and specificity of each of these antigens were assessed using sera from sheep experimentally infected with graded monospecific infections of E granulosus, T hydatigena or T ovis eggs and sera from naturally infected aged sheep. The ability of eight of the antigens to detect the antibody response to larval cestode infection was also compared over 12 months using sera from serial bleedings. Using the ELISA, all of the antigens were able to detect the presence of larval cestodes, even in sheep with only one or two cysts. Over 12 months, the antibody responses were not generally statistically related to the total number of cysts present in the animals. None of the antigens was able to detect specific infections only. The antigen with least non-specific background activity, which consistently detected the highest antibody titres in the sera of all infected animals was the secretion from T ovis worms cultured in vitro, and is, therefore, the antigen of choice for the detection of non-specific infections with larval cestodes in sheep.

Animals↗
PubMedDate not supplied

[Study of the cumulation, desorption and mechanism of action of organochlorine pesticides on fish cestodes].

The distribution of residues of DDT and its metabolites (DDD and DDE) in tissues of Triaenophorus nodulosus and its host was studied. It has been noted that cestodes can accumulate chlororganic substances in great quantity. The ability of Bothriocephalus gowkongensis has been established to dechlorate pp-DDT and to excrete pp-, op- and mp-DDD from the organism. Pp-DDT decreases the glycogene content and causes the rise of amylolytic activity in the above cestodes in acute tests. The effect of pp-DDT on the locomotor activity of cestodes is of two-phase character. The first one is associated with the muscular influence, the second one-- with neurotrophic effect. A high toxicity of mp-DDD )0.1 mg/l) for the locomotor activity of cestodes as compared with the effect of pp- and op-DDD was revealed.

Absorption↗
PubMed2006

Avian cestodes affect the behaviour of their intermediate host Artemia parthenogenetica: an experimental study.

The brine shrimp Artemia parthenogenetica (Crustacea, Branchiopoda) is intermediate host for several cestode species whose final hosts are waterbirds. Previous field studies have shown that brine shrimps infected with cestodes have a bright red colour and are spatially segregated in the water column. However, the ethological mechanisms explaining such field observations are unknown. Changes in appearance and behaviour induced by trophically transmitted parasites have been shown to increase the risk of predation by the final host. In this experimental study, we compared the behaviour of uninfected Artemia and those infected by avian cestodes. We found that parasitised individuals behave differently from unparasitised ones in several ways. In contrast to uninfected individuals, infected brine shrimps were photophilous and showed increased surface-swimming behaviour. These observations suggest that the modified behaviour (in addition to the bright red colour of the majority of the infected individuals) results in infected brine shrimps becoming more vulnerable to avian final hosts, which facilitates parasite transmission. We discuss our results in terms of the adaptive nature of behavioural changes and their potential implications for the hypersaline ecosystem.

Animals↗
PubMed2002

Cestode parasites: application of in vivo and in vitro models for studies on the host-parasite relationship.

Cestode worms, commonly also known as 'flat' worms or tapeworms, are an important class of endoparasitic organisms. In order to complete their life cycle, they infect intermediate and definitive hosts in succession, through oral ingestion of eggs or larvae, respectively. Serious disease in humans or other mammalian hosts is mostly caused by the larval stages. Echinococcus spp. and Taenia spp. have been extensively investigated in the laboratory due to the fact that they represent important veterinary medical challenges and also cause grave diseases in humans. In contrast, Hymenolepis spp. and Mesocestoides spp. infections are relatively rare in humans, but these parasites have been extensively studied because their life cycle stages can be easily cultured in vitro, and can also be conveniently maintained in laboratory animal hosts. Thus they are more easily experimentally accessible, and represent important models for investigating the various aspects of cestode biology. This review will focus on in vitro and in vivo models which have been developed for studies on the host-parasite relationship during infection with Echinococcus, Taenia, Hymenolepis, Mesocestoides and Spirometra, and will cover the use of these models to investigate the morphology and ultrastructure of respective genera, the immunological relationship with the host and the development of vaccination approaches, as well as applications of these models for studies on parasite metabolism, physiology and gene expression. In addition, the use of these models in the development of chemotherapeutic measures against cestode infections is reviewed.

Animals↗
PubMed1991

The helminth fauna of the common seal (Phoca vitulina vitulina, Linné, 1758) from the Wadden Sea in Lower Saxony. Part 1: Trematodes, cestodes and acanthocephala.

Between August 1988 and January 1989 110 common seals found dead along the coast of Lower Saxony were investigated for the occurrence of trematodes, cestodes and acanthocephala. Two fluke species, Cryptocotyle lingua Creplin, 1825 and Phagicola septentrionalis Van Den Broek, 1967, two tapeworm species Diphyllobothrium cordatum Leuckart, 1863 and Diphyllobothrium elegans Krabbe, 1865, and the acanthocephala species Corynosoma strumosum Rudolphi, 1802 were found. Phagicola septentrionalis and the cestodes were always found together with Cryptocotyle lingua. The prevalence of Phagicola septentrionalis, the diphyllobothriids and the acanthocephala increased with increasing age of the pinniped host. The worm counts of all species appeared to increase with increasing age of the host. The adult male seals were more often infested with Phagicola septentrionalis and cestodes than the female adults and the younger pinnipeds. There was no correlation between blubber thickness of the seals and parasitic infection. The prevalence of the diphyllobothriids and the intensity of the infection with acanthocephala were higher in seals found in the eastern part of the Wadden Sea.

Acanthocephala↗
PubMed2000

Trypanorhynch cestodes from Indonesian coastal waters (East Indian Ocean).

Results of a study on trypanorhynch cestodes of fishes from Indonesian coastal waters are presented. A new species, Dasyrhynchus thomasi sp. n., is described, and five species are recorded which all represent new locality records: Tentacularia coryphaenae Bosc, 1797; Nybelinia africana Dollfus, 1960; Nybelinia scoliodoni (Vijayalakshmi, Vijayalakshmi et Gangadharam, 1996); Sphyriocephalus dollfusi Bussieras et Aldrin, 1968; and Otobothrium penetrans Linton, 1907. Their known ranges of distribution are extended to the East-Indian Ocean. Scanning and transmission electron microscopy was used to clarify details of the tentacular armature and surface morphology of T. coryphaenae, D. thomasi and O. penetrans. In T. coryphaenae, hook-like microtriches along the bothridial tegument are embedded in the distal cytoplasm, sometimes showing a split base. The solid tentacular hooks are embedded into a fibrillar, highly ordered tentacular wall. D. thomasi is distinguished by its characteristically shaped bothridia and a triple chainette with winged hooks on the external surface of the tentacle. Tufts of microtriches with ciliated sensory receptors are regularly arranged on the bothridial surface of O. penetrans. They show similarities to sensory receptors reported from other trypanorhynch cestodes. Otobothrium pephrikos Dollfus, 1969 is considered a junior synonym for O. penetrans, and the variability of the scolex within trypanorhynch cestodes is emphasised.

Animals↗
PubMed2001

Diphyllidean cestodes of the Gulf of California, México with descriptions of two new species of Echinobothrium (Cestoda: Diphyllidea).

As part of a survey of parasites of elasmobranchs in the Gulf of California, a second and final report of the diphyllidean cestodes resulting from the survey is presented. Of 43 species of elasmobranchs examined for parasites, 7 (Rhinobatos productus, Rhinobatos leucorhynchus, Myliobatis californicus, Myliobatis longirostris, Urobatis halleri, Urobatis maculatus, and Rhinoptera steindachneri) were found to host diphyllidean cestodes, all belonging to Echinobothrium. No species of either of the other 2 diphyllidean genera, Dirrachybothridium or Macrobothridium, were discovered. A greater diversity of diphyllideans was found in 1996 than in 1993. Two new species, Echinobothrium hoffmanorum n. sp. and Echinobothrium rayallemangi n. sp. are described from the spiral intestines of U. maculatus and R. leucorhynchus, respectively. Echinobothrium hoffmanorum is unique in its possession of the following combination of characters: 19-21 apical hooks in each dorsoventral group, 12-22 lateral hooklets in each group, 10-17 cephalic peduncle spines per column, 4-8 testes, 4-10 segments and eggs with a single filament. Echinobothrium rayallemangi is unique in its possession of the following combination of characters: 23 apical hooks in each dorsoventral group, 20-23 lateral hooklets in each group, 2-5 cephalic peduncle spines per column, 4-6 testes, and 4-6 segments. These 2 new species, together with Echinobothrium mexicanum and Echinobothrium fautleyae, brings the total number of diphyllideans known from the Gulf of California to 4. The survey of diphyllidean cestodes of the Gulf of California has resulted in a new host record for Echinobothrium for each of the host species mentioned above, with Rhinobatos and Urobatis representing new host genera and Urolophidae a new host family for Echinobothrium.

Animals↗
PubMed1999

[Cestode infections in 1997].

In 1997, 736 intestinal cestode cases were registered in Poland. Among them 634 were caused by T. saginata, 6 by T. solium, 63 by Taenia sp, 15 by Hymenolepsis sp, and 2 by D. latum and D. caninum. Moreover, 27 cases of larval cestode infections were also registered. Four of them were caused by larvae of T. solium and the remaining ones bz E. granulosus. The obtained results confirmed the decreasing frequency of infections with intestinal cestodes in Poland.

Adult↗
PubMed2000

[Cestode infections in 1998].

In 1998, 603 intestinal cestode cases were registered in Poland. Among them 516 were caused by T. saginata, 5 by T. solium, 59 by Taenia sp., 2 by Hymenolepis nana and 1 by D. latum. Moreover, 31 cases of larval cestode infections were also registered. Three of them were caused by larvae of T. solium and the remaining ones by E. granulosus. The obtained results confirmed the decreasing frequency of infections with intestinal cestodes in Poland.

Adolescent↗
PubMedDate not supplied

[Distribution of the cestode Caryophyllaeides fennica (Cestoda: Lytocestidae) in the population of cyprinid fish in the Rybinsk water reservoir].

The distribution of the cestode Caryophyllaeides fennica in populations of the ide, roach, white bream and bream from the Rybinsk reservoir has been analyzed in regard to fish age. The relative abundance of C. fennica in populations of each host species was calculated as product of the helminthes abundance by the fish number in age groups. The highest prevalence and abundance of cestodes was found in the ide. All age classes of this species were infected, with the maximum in fishes of the age 3+ ... 5+. The roach is infected with C. fennica till only 10-year age; brean is infected till the age 4+. In the white bream C. fennica is an occasional parasite. The cestode number among hosts was as follows: bream--68%; roach--26%, ide--5%, white bream--1%. Different approaches to the estimation of the parasite abundance distribution among several host species (in terms of mean prevalence and intensity of the relative abundance of parasites) are discussed.

Aging↗
PubMedDate not supplied

[Branchiopods--intermediate hosts of the cestode Anomolepis averini (Spassky et Yurpalova, 1967)(Cestoda: Dilepididae)].

In the biocoenosis of the lake Tengiz (Central Kazakhstan) Artemia salina (3.3%) and Branchinella spinosa (0.22%) were found to be infected with larvae of cestodes--delipidids Anomolepis avertini (Spassky et Yurpalova, 1967). Phalaropus lobatus from this water body was also infected (13.7) with this cestode, the infection intensity being from 1 to 15 strobiles in one bird. Figures and morphological description of cysticercoids and mature cestodes of Anomolepis averini are given.

Animals↗
PubMedDate not supplied

[Biotope distribution of cestodes from the common shrew Sorex araneus in southern Karelia].

Specific features in the formation of cestode species composition in the common shrew in different biotopes have been analyzed. Four categories of parasites have been recognized depending on a degree of dominance: dominants (Neoskrjabinolepis singularis, Molluscotaenia crassiscolex), subdominants (Ditestolepis diaphana), adominants A (Staphylocystis furcata, Vigisolepis spinulosa, adominants B (Hymenolepis scutigera, Dilepis undula, D. secunda, Taenia mustelae). A significant similarity was discovered between the species diversity and the dominance characteristics of cestodes. It was found that the distribution of mass species of parasites in the host population corresponds to the gamma distribution model. In regard to cestodes examined, a hypothesis considering the spatial structure and size of territory occupied by stable parasitic system is put forward.

Animals↗
PubMed1988

Application of biotechnology methods to the study of cestodes.

The advent of biotechnology has invigorated research on the control of cestode diseases, especially cysticercosis infections in man and animals. The utilization of hybridoma technology to produce antigen-specific monoclonal antibodies has resulted in great strides towards obtaining pure antigens relevant for immunodiagnostic purposes and for research on vaccines. However, the isolation and identification of antigens is only the initial step in the development of such reagents. Production of antigens in quantities sufficient for research/development and commercialization is hampered by the scarcity of viable parasite material for extraction. Expectations are that this problem can be surmounted by application of recombinant DNA methods to produce cloned genes for antigen expression in cultured microorganisms or cells. Remarkable progress has been made recently in isolating and cloning genes from several important cestode species and antigens have been expressed in vitro with genes cloned from Taenia taeniaformis and T. hydatigena. Although these early efforts have not as yet resulted in practical antigen production, the prospects for doing so appear good. The complex epidemiology of cestode diseases is another research subject that has benefited from the successful application of the tools of biotechnology. For example, the greater precision in typing biological variants afforded by DNA analysis has led to important revisions of the understanding of hydatid disease. DNA probes are now available for Echinococcus spp, which are effective for typing isolates. These probes may also find use as reagents for distinguishing eggs of Echinococcus from other taeniid eggs, a serious difficulty for field investigations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗