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At least 217 records · Page 12Linked to original sources
PubMed1985

Attempted mathematical models of seasonal dynamics of cestode infections in intermediate and final hosts.

The possibility of describing cestode infection dynamics in various host groups (e.g in birds, fishes and copepods) by trigonometric and parabolic polynomials is examined. The necessity of observing certain requirements during data collection for the correct application of the examined models is shown; the possibility of applying a parabolic polynomial in case of non-observing of some of these requirements has been found. The mathematical models obtained are of prognostic value and may serve as a measure of the uniformity and validity of the empirical data.

Animals↗
PubMed1985

Anthelmintic efficacy of flubendazole paste against nematodes and cestodes in dogs and cats.

Small dogs and cats, naturally infected with nematodes and cestodes, were used in a critical test under laboratory conditions to determine the palatability and efficacy of flubendazole as a past formulation. Subsequently, a control test in dogs was conducted under field conditions. A 4.4% past formulation was given at a dosage of 22 mg/kg of body weight once a day for 2 or 3 consecutive days. In a critical test in dogs, the efficacy against Toxocara canis was 97.4% after a 2-day administration and 100% after 3 days. Toxascaris leonina seemed to be the most susceptible worm species, since either 2 or 3 treatments were 100% active. The efficacy against Uncinaria stenocephala was 97.5% after 2 treatments; the same dose level for 3 days improved the efficacy to 100%. The efficacy was 100% for the removal of Trichuris vulpis after a daily dosage for 2 days and 96.7% after 3 days. One of 2 dogs infected with Taenia pisiformis was cleared of the infection after a 2-day treatment, and 3 of 4 dogs were cleared after a 3-day regimen. All cats were cleared of Toxocara cati after 2 or 3 days of treatment. One of 2 cats infected with Hydatigera taeniaeformis was cleared of the infection after a 2-day treatment; a 3-day treatment in 7 cats was 100% effective. The results in the laboratory test in dogs were confirmed under field conditions by a control test, based on the reduction of eggs per gram of feces count after treatment. The paste formulation was well accepted by all dogs and cats without any side effects.

Administration, Oral↗
PubMed1980

Macaca mulatta--a new host for Choanotaenia cestodes.

A juvenile Macacca mulatta that died following a peracute illness was found to be harboring about 25 mature Choanotaenia infundibulum tapeworms. These cestodes commonly infest birds, occasionally insectivores and rodents but have never been reported in nonhuman primates.

Animals↗
PubMedDate not supplied

[Cestode adaptation to life cycles].

There are two groups of cestode adaptations. One of them makes it possible for particular developmental stages to be adapted to their particular environment (including second order environment). The second one involves passing through the entire life circle: transition from one environment to another, releasing from protective shells, host intrusion, population density regulation at different developmental stages. Spectrum of adaptive reactions on the life cycles is determined by peculiarities of parasite systems.

Adaptation, Physiological↗
PubMedDate not supplied

[Lactate dehydrogenase activity and changes in its isoenzyme spectrum in the liver of the bream Abramis brama parasitized by pleurocercoids of the cestode Digramma interrupta].

Changes of lactate-dehydrogenase (KF 1.1.1.27) activity have been studied in the liver of the bream been infected with pleurocercoids of the cestode Digramma interrupta. It is showed, that an increase of enzyme activity depends upon a slowly migrating from LDH-6. Problems of interaction at the level of substrate within a system parasite-host is considered.

Animals↗
PubMed1996

Two new species of tetraphyllidean cestodes in Himantura pacifica (Chondrichthyes: Myliobatiformes: Dasyatididae) from the northwest coast of Costa Rica.

Two new species of tetraphyllidean cestodes inhabiting Himantura pacifica from the northwest coast of Costa Rica are apparently most closely related to species inhabiting Himantura schmardae from the Atlantic coast of Colombia. Acanthobothroides pacificus n. sp. differs from Acanthobothroides thorsoni, the only other species in the genus, primarily by having smaller lateral (98-123 microns rather than 168-198 microns long) and medial (handles 92-116 microns rather than 162-168 microns long) hooks, and more testes (up to 125 rather than up to 97) per proglottis. The generic diagnosis of Acanthobothroides is modified to include the presence of a small inner prong on the large medial bothridial hooks. Rhinebothrium geminum n. sp. and Rhinebothrium magniphallum are the only 2 species in the genus possessing unusually long cirrus sacs, extending from the genital atrium all the way to the ovarian isthmus; R. geminum averages 12 (12-14) loculi per bothridium and 11 (9-12) testes, whereas R. magniphallum averages 17 (16-18) loculi and 14 (10-16) testes per proglottis.

Animals↗
PubMed1976

Seasonal periodicity of three species of caryophyllaeid cestodes in the creek chubsucker, Erimyzon oblongus (Mitchill), in North Carolina.

One hundred and seventy-two specimens of Erimyzon oblongus from Lake Raleigh, North Carolina, were examined for caryophyllaeid cestodes from December 1972 to July 1974. Monobothrium ulmeri, Biacetabulum meridianum, and an undescribed species of Penarchigetes were recovered from the "stomach," "pyloric bend," and the first loop of the small intestine of the suckers. Infections of M. ulmeri were limited to an 8-month period and were seasonally periodic in prevalence, mean intensity, maturation, and length distribution. A "temperature dependeant rejection response" is discussed as a possible factor involved in the periodicity of this species. The maturation of M. ulmeri corresponded closely to the host's reproductive cycle, and may have been affected by changes in the host's hormonal levels during the spring. Infections of R. meridianum were present throughout the year, and exhibited a seasonal periodicity in prevalence, maturation, and length distribution. The mean intensity of infection suggests that the establishment of this species is inhibited by heavy burdens of M. ulmeri. Penarchigetes sp. was nonseasonal in prevalence, mean intensity, and maturation. The continuous availability of infective procercoids and the lack of a sucker "rejection response" are discussed as possible explanations for this destribution. Unlike B. meridianum and Penarchigetes sp., the mean intensity of M. ulmeri showed a close relationship with host sex.

Animals↗
PubMed1997

Heavy metal concentrations in adult acanthocephalans and cestodes compared to their fish hosts and to established free-living bioindicators.

Intestinal helminths of fish caught from freshwater and brackish water biotopes throughout Europe were analysed by electrothermal atomic absorption spectrometry for their heavy metal (Pb and Cd) levels. The metal concentrations of the parasites were compared to those of different organs (muscle, liver, intestine) of the fish hosts and to those detected in the whole bodies of the respective intermediate hosts. The three acanthocephalan species analysed contained very high amounts of Pb and Cd. The lead level of Pomphorhynchus laevis was up to 2700 times higher and the cadmium concentration was approximately 500 times higher than the muscle of chub, its host. Concurrent analysis of larval acanthocephalans in the crustacean intermediate host indicated that the bioconcentration of heavy metals by these parasites occurs only in the final host. In two species of cestodes accumulation of metals was also recorded although the degree of bioconcentration was somewhat lower. Nevertheless, Monobothrium wageneri contained 75 times more Pb and 43 times more Cd than the muscle of its host, the tench. In contrast, no bioconcentration of heavy metals was detected in the swimbladder nematode Anguillicola crassus. It contained less lead than the muscle of its final host, the eel. In one biotope the concentration of 18 elements was compared between the whole soft tissues of the zebra mussel, Dreissena polymorpha, the parasite Acanthocephalus lucii and its final host, perch. The acanthocephalan accumulated most of the elements to considerably higher concentrations than the zebra mussel, which has been considered an effective bioindicator of heavy metals. The sessile nature of the zebra mussel may allow a better identification of small-scale local differences in environmental heavy metal contamination. However, acanthocephalan parasites will provide an ecologically-important index of average exposure of their mobile fish host to biologically-available metals within its natural range.

Acanthocephala↗
PubMed1985

Serotoninlike immunoreactivity in the cestode Hymenolepis diminuta.

Serotoninlike immunoreactivity in the cestode Hymenolepis diminuta was studied at the light microscope level by using an antibody specific to serotonin. The rostellum, the cerebral ganglia and commissure, and the strobila contained numerous process-free, unipolar and multipolar serotoninlike immunoreactive cells. The suckers contained a plexus of branching immunoreactive fibers. In the strobila the multipolar cell bodies were situated laterodorsal and lateroventral to the longitudinal nerve cords, from which neurites were directed to the contralateral and ipsilateral nerve cord to form up to three transverse commissures per proglottid. Secondary varicose branches passed anteriorly, posteriorly, and obliquely along the proglottids at the level of the deep longitudinal muscles. Other varicose multi-branching neurites passed centrifugally from the primary and secondary neurites, forming vertebratelike en passant or terminal varicosities on the deep longitudinal muscles with bulbous or spinose terminals at the level of the superficial longitudinal muscles, or in the cortical parenchyma. Serotoninlike immunoreactivity was seen on the external seminal vesicle, the sphincter and cirrus sac, and the proximal portion of the vagina. Varicose terminals were concentrated at the sphincter. The close association of serotoninlike immunoreactive terminals and varicosities with the longitudinal muscles gives credence to the concept that serotonin functions as a neuromuscular transmitter or modulator in the platyhelminths.

Animals↗
PubMed2006

Localization, specific activity, and molecular forms of acetylcholinesterase in developmental stages of the cestode Mesocestoides corti.

The nervous system of flatworms is quite simple although there is increasing evidence indicating that it is chemically complex. Studies of the nervous system in these animals have only been performed in the larval stage or in the adult worms, which are easy to obtain in nature, while the description of the nervous system in developing stages of these organisms is missing. Mesocestoides corti is a parasitic platyhelminth whose larvae can be induced in vitro to develop to adult, sexually mature worms, opening the possibility of studying the nervous system of a flatworm in different stages of development. Here, we describe the presence, activity, location, and molecular forms of acetylcholinesterase (AChE) in different stages of development of M. corti, from the larvae to adult forms of this endoparasite, obtained in in vitro cultures after induction of the larval stage with trypsin. Our results point to AChE as a molecular marker of the nervous system in platyhelminthes. The change in molecular forms of this enzyme and the increase in its activity during development from larvae to adult worm may reflect the presence of a more complex nervous system, necessary to adjust and coordinate the movement of a much bigger structure. A relationship between the development of the reproductive apparatus in segmented and adult worms with a more complex nervous system in these stages is also apparent. Finally, our study opens the possibility of applying anti-AChE as more effective therapeutic strategies against cestode parasites.

Acetylcholinesterase↗
PubMed1975

Competition between two closely related Tetrabothrius cestodes of the fulmar (Fulmarus glacialis L.).

The two congeneic Tetrabothrius cestodes of the fulmar are so closely related that they can only be reliably distinguished by differences in the number of testes. The two species show a considerable distributional overlap along the intestine. Statistically it can be shown that high numbers of the common, anteriorly situated species (T. minor) affect the distribution of the rarer, more posteriorly situated species (T. procerus), causing the latter to occupy a more posterior site in the intestine. Several possibilities are discussed concerning the mechanism by which T. procerus is affected, and how this mildly competitive situation is maintained. It is probable that niche segregation between the two species is more or less complete, but that this is reinforced in concurrent infections by interactive site segregation.

Animals↗
PubMed1975

[Electron microscope study of spermatogenesis in two cestodes acanthobothrium filicolle benedenii Loennberg, 1889 and Onchobothrium uncinatum (Rud., 1819) (Tetraphyllidea, Onchobothriidae) (author's transl)].

The spermatogenesis, spermatozoon differentiation and fine structure of Acanthobothrium filicolle benedenii Loennberg, 1889 and Onchobothrium uncinatum (Rud., 1819) were studied by means of light and electron microscopy. Spermatogenesis in both species is of the rosette type. During sperm differentiation, the five following stages have been distinguished: (1) formation of arching membranes and differentiation zone; (2) nuclear elongation; (3) formation of two flagella with a median cytoplasmic process; (4) flagellar rotation; (5) fusion of two flagella with the median cytoplasmic process induced by the migration of nucleus into the latter. The mature spermatozoa of both species are threadlike structures about 250 mum long. They consist of two axonemes of the platyhelminth type (9+1 pattern), elongated nucleus and cortical microtubules embedded in a cytoplasmic matrix containing numerus beta-glycogen particles. The body which appears on cross-sections as crest, lateral with respect to the axoneme, is present in both species. Such a body is reported for the first time in Cestode spermatozoa. There is no mitochondrion in the two Onchobothriidae sperms studied.

Animals↗
PubMed1989

Demonstration of intense glutamate-like immunoreactivity in the longitudinal nerve cords of the cestode Hymenolepis diminuta.

Glutamate-like immunoreactivity in the cestode Hymenolepis diminuta was studied at the light microscopic level using an antibody specifically directed against a reduced conjugate of glutamate linked to protein by glutaraldehyde. Relatively low levels of glutamate-like immunoreactivity were present in the subtegumental region, which was presumed to reflect an active metabolic pool. Relatively high levels of this reactivity were observed in the longitudinal nerve cords and associated cells, and somewhat lower levels were occasionally noted in ring commissures. The present data in conjunction with previous studies on glutamate in H. diminuta, support the hypothesis that glutamate is an excitatory neurotransmitter in the platyhelminths.

Animals↗
PubMed2000

Sensory receptors and surface ultrastructure of trypanorhynch cestodes.

The scolices of six different trypanorhynch species--Heteronybelinia alloiotica (Dollfus, 1960), Pseudolacistorhynchus noodti Palm, 1995, Otobothrium cysticum (Mayer, 1842), O. penetrans Linton, 1907, Poecilancistrum caryophyllum (Diesing, 1850), and Prochristianella hispida (Linton, 1890)--were examined for surface morphology and the occurrence of sensory receptors. Filamentous microtriches with different internal ultrastructural features were found. Acerosate, hook-like, and spiniform microtriches were detected on the surface of the tentaculariid H. alloiotica. Their internal structure clearly differed from that of pectinate microtriches observed in the other five trypanorhynch species lacking a basal and a junctional region. All pectinate microtriches had the same general architecture, independent of the number of digitiform processes. All trypanorhynchs studied harbored ciliated sensory receptors within the tegument. Even though sensory receptors were scarce in H. alloiotica, they were more abundant in the lacistorhynchid P. noodti and the otobothriids P. caryophyllum and O. penetrans, which exhibited two, six, and three kinds of receptors, respectively. Bothridial pits in O. penetrans and O. cysticum were invaginations of the bothridial surface, being characterized by the lack of sensory receptors and the presence of characteristic microtriches. These differed from other microtriches in that they were larger and had a base consisting of a widely enlarged matrix. The occurrence of different kinds of microtriches and sensory receptors within trypanorhynch cestodes is summarized, and the meaning of these surface structures and of bothridial pits as characters within future trypanorhynch classification is emphasized.

Animals↗
PubMed2002

Ultrastructure of the spermatozoon of the pseudophyllidean cestode Eubothrium crassum (Bloch, 1779).

The fine structure of the mature spermatozoon of the pseudophyllidean tapeworm Eubothrium crassum, a parasite of salmonid fishes, has been studied by transmission electron microscopy for the first time. The mature spermatozoon of E. crassum is filiform and tapered at both extremities. It contains two axonemes of unequal length showing the 9 + "1" pattern of Trepaxonemata. The anterior extremity exhibits a crested body 50-100 nm thick. It spirals around the outside of the anterior region of the spermatozoon. The nucleus is electron-dense, exhibiting a fibrous appearance in its middle (the broadest) region. The cortical microtubules are of two types and are situated parallel to the spermatozoon axis. The cytoplasm is slightly electron-dense and contains numerous electron-dense granules in region II of the spermatozoon. A ring of electron-dense, centred microtubules surrounds the axoneme, together with the underlying ring of moderately electron-dense, subjacent submicrotubular material in region V. The anterior and posterior extremities of the spermatozoon lack cortical microtubules and contain a single axoneme. Our results reveal several peculiarities, in which the spermatozoon of E. crassum differs from those of other pseudophyllidean cestodes.

Animals↗
PubMed2005

Spermiogenesis and sperm ultrastructure of the pseudophyllidean cestode Triaenophorus nodulosus (Pallas, 1781).

Spermiogenesis and ultrastructure of the spermatozoon of the pseudophyllidean cestode Triaenophorus nodulosus (Pallas, 1781), a parasite of pike Esox lucius, has been studied by transmission electron microscopy. Spermiogenesis involves firstly the formation of a zone of differentiation with two centrioles associated with striated roots, and an intercentriolar body between them, subsequent growth of the two flagella of unequal length, and a formation of a median cytoplasmic process exhibiting patches of dense material. The nucleus penetrates into spermatid body after flagellar rotation and proximo-distal fusion has started. The mature spermatozoon of T. nodulosus is filiform and contains two axonemes of 9+"1" pattern of the Trepaxonemata, nucleus, cortical microtubules parallel to the spermatozoon axis, and electron-dense granules. The anterior extremity of the gamete contains a single centriole surrounded by numerous electron-dense tubular structures exhibiting spiral arrangement and giving rise to lateral projections, which correspond to the crested body. When the crested body disappears, the spiral pattern of electron-dense tubular structures is changed into a ring, persisting until the centriole of the second axonemes appears. This structure of the crested body of T. nodulosus is unique among the Eucestoda.

Animals↗
PubMed2005

Vitellogenesis in two spathebothriidean cestodes.

Vitellogenesis in two spathebothriidean tapeworms, dixenous adult Cyathocephalus truncatus and monoxenous progenetic Diplocotyle olrikii, has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for glycogen. Each vitelline follicle consists of vitellocytes at various stages of development and one irregularly shaped interstitial cell. Projections of the interstitial cell enclose the vitellocytes and extend as a cytoplasmic sheath on the follicular periphery. An outer thin fibrous layer (= extracellular lamina) covers the cytoplasmic sheath in C. truncatus, but lacks in D. olrikii. Maturing and mature vitellocytes contain vitelline material in the form of single small shell globules that gradually fuse and give rise to the large shell globule clusters. Morphology of shell globule clusters differs slightly in both species. In addition, single "lamellar" granules are present in the cytoplasm of vitellocytes of C. truncatus, but not in D. olrikii. Both electron lucent and electron dense lipid droplets are present in the vitellocytes of C. truncatus, whereas only electron dense lipids occur in D. olrikii. A single lipid droplet turns up occasionally in the nuclei of some of the vitellocytes of C. truncatus. The ultrastructural features of vitellogenesis in spathebothriideans resemble those reported previously in "lower" cestodes, especially in pseudophyllideans.

Animals↗