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At least 1,243 records · Page 69Linked to original sources
PubMed1996

Infectivity of Hymenolepis diminuta for the jird, Meriones unguiculatus, and utility of this model for anthelmintic studies.

The jird (Meriones unguiculatus) has been shown to be a useful model host for the cestodes Taenia crassiceps and Echinococcus multilocularis. This report outlines a novel model in which hydrocortisone-treated jirds (0.02% in the feed) are infected with another cestode, Hymenolepis diminuta. Jirds were inoculated with 5 freshly harvested cysticercoids of H. diminuta prior to (day 0, -1, or -5) or after (day 1 or 5) switching to medicated feed; in some cases, jirds were never medicated. On days 7, 14, 21, or 28 postinoculation (PI), jirds were killed by CO2 inhalation and their small intestines were examined for tapeworms. Hymenolepis diminuta established, grew, and developed to the gravid adult state in jirds. They persisted longer in medicated (21 days) than in nonmedicated (7 days) animals, and generally higher levels of infection were obtained when jirds were inoculated immediately prior to switching to medicated feed. Treatment of infected jirds on day 4 or days 4, 5, and 6 PI with selected anthelmintics followed by necropsy on day 7 PI discriminated drugs with known activity against tapeworms from those with little or no activity. This rodent in vivo model should provide a useful adjunct for anthelmintic studies.

Animals↗
PubMedDate not supplied

[Development of the neural apparatus of Triaenophorus nodulosus (Cestoidea, Pseudophyllidae) during ontogenesis].

The anatomy of the nervous apparatus of Triaenophorus nodulosus at all stages of its life cycle was studied by means of Zherebtsov's hystochemical method. Judging by the cholinesterase activity the mass of nerve cells is situated in the oncospheres of the coracidium. At the procercoid stage the ortogonal nervous system arises with three pairs of the longitudinal nervous trunk. In plerocercoids the number of longitudinal trunks increases up to 7 pairs, the rough nervous plexus and inner plexus develop too, In mature, cestodes only secondary changes take place associated with the development of the genital system. Both in larvae and adults all longitudinal trunks are situated at the same level, on the border of the cortical and medullary parenchyma, and only the inner nervous plexus first described by the authors from cestodes passes through the medullary parenchyma. The arrangement of all elements of the nervous apparatus at the same level corresponds from the authors point of view to the most primitive state of the nervous system in the order Pseudophyllidea.

Aging↗
PubMedDate not supplied

[The life cycle and fine morphology of the embryophores in Microsomacanthus paraparvula (Cestoda: Hymenolepididae), a parasite of diving ducks in Chukotka].

It was found out, that the cestode Microsomacanthus paraparvula Regel, 1994 being a common parasite of diving ducks in Chukotka uses a caddisfly Grensia praeteria (Trichoptera) as an intermediate host in its life cycle. Mature fragments of the cestode have been collected from droppings of the experimentally infected nestling of the kittiwake Rissa tridactyla (non-specific host) and used for the fine morphology study of embryonic shells and for an infection of intermediate hosts.

Animals↗
PubMed1997

Autoradiographic analysis of the germinative tissue in evaginated Taenia solium metacestodes.

Evaginated Taenia solium metacestodes dissected from infected pork meat were incubated in vitro in RPMI 1640 medium with tritiated thymidine, washed, and further incubated for various chase periods. Worms were fixed and embedded in Poly/Bed and sections were processed for autoradiography. Results showed that all longitudinal sections had a germinative region located 500-700 mm posterior to the apex of the scolex with tegumentary cytons arranged in staggered columns perpendicular to the tegument. After 6-hr pulse and 0-12-hr chase periods, a large number of labeled cells were found in the parenchyma and tegumentary wall, included were myocytons, calcareous corpuscle cells, flame cells, osmoregulatory channel cells, and, in the medullary parenchyma, labeled undifferentiated round cells with a large nucleus, prominent nucleolus, abundant ribosomes, and no cytoplasmic organelles. These undifferentiated cells were not labeled after 24-hr and 48-hr chase periods, an observation that strongly suggests these cells divide and migrate toward the tegument in a pattern similar to that described for other cestodes. The morphology and localization of these cells support the view that they are stem cells that give rise to the various cell types of the tegumentary wall. The results indicate that T. solium contains a germinative tissue similar to that described in other cestodes, in which stem cells proliferate continuously, differentiate, and migrate to the tegument, constituting the main process by which these worms develop from metacestode to the adult stage.

Animals↗
PubMed1976

The effect of gamma radiation on the cysticerci of Taenia solium.

Cysticerci of Taenia solium were exposed to gamma radiation in doses varying from 20-140 krad. Radiation had an adverse effect on the ability of the cysticerci to evaginate in vitro after a time lag of 9 days. This effect was most marked at doses of 100 krad and higher, thus no cysticerci exposed to 140, 120 and 100 krad evaginated after 12, 18 and 21 days, respectively. On Day +24, when 60% of the control cysticerci evaginated, 55%, 50%, 30% and 40% of the cysticerci exposed to 20, 40, 60, and 80 krad, respectively, evaginated in vitro. Cysticerci exposed to radiation doses of 20-120 krad are as infective to golden hamsters as are unirradiated cysticerci. Cestodes resulting from irradiated cysticerci, however, cannot maintain themselves indefinitely, and are excreted or digested at varying times from Day +12 onwards. Moreover, cestodes resulting from such irradiated cysticerci do not grow, but are resorbed, and finally consist of only a scolex. By Day +30 the mean length of the worms resulting from the unirradiated cysticerci is 173,8 mm, while those resulting from cysticerci exposed to 20 and 40 krad consist of scolices only and the hamsters fed material exposed to 60 krad were negative. It appears, therefore, that radiation inhibits the ability of the cells in the neck region to divide and thus form new proglottids. Carcasses infested with cysticercosis can possibly be rendered fit for human consumption by exposure to gamma radiation at doses between 20 and 60 krad.

Animals↗
PubMed1997

A comparison of the helminth communities in Anas undulata, Anas erythrorhyncha, Anas capensis and Anas smithii at Barberspan, South Africa.

Examination of the helminth communities in 25 yellow-billed ducks (Anas undulata), 21 red-billed ducks (Anas erythrorhyncha), ten Cape teal (Anas capensis) and seven Cape shovellers (Anas smithii) that had overwintered at Barberspan, revealed differences in community structure. Infracommunities in yellow-billed and red-billed ducks were characterized by low diversity and high eveness, and generally consisted of less than 100 helminths per duck. Similarity values (mean percent similarity and mean Jaccard's coefficients) were low. In contrast, infracommunities in Cape teal and Cape shovellers were more diverse, displayed low eveness values and consisted of far greater numbers of helminths. Mean similarity values for the infracommunities in Cape teal and Cape shovellers were much higher than those in yellow-billed or red-billed ducks. The component communities in all four duck hosts were species rich. Those in yellow-billed and red-billed ducks, however, consisted predominantly of satellite species and no core species were present, whereas those in Cape teal and Cape shoveller included several core species. Cape teal and Cape shovellers each had a group of recurrent species but there was not much of a tendency for species to co-occur in yellow-billed and red-billed ducks. Multivariate analysis revealed a greater similarity between the communities in Cape teal and Cape shovellers than between the latter and the communities in yellow-billed or red-billed ducks. Communities in Cape teal and Cape shovellers could be distinguished from each other by the presence or absence of particular cestode species. The communities in these two species could be distinguished from those in yellow-billed or red-billed ducks by a suite of cestode species that was absent in the latter two. Two recurrent groups, consisting of eight and two species, were identified in the compound community. Each group consisted of species found predominantly in Cape teal and Cape shovellers. Patterns seen in the helminth communities of the various hosts reflected differences in diet, but other factors, including feeding behaviour, spatial segregation and host specificity, may also have had an effect.

Animals↗
PubMed1976

Polymorphism of larvae of the genus Aploparaksis Clerc, 1903 (Hymenolepididae).

The larvae of 12 cestode species of the genus Aploparaksis have been studied. In order to confirm the determination, the definitive hosts, birds, were experimentally infected with 5 species and the intermediate hosts, oligochaetes, with 6 species of cestodes. A great variability was observed in the morphology of tail appendix of cysticercoids belonging to five types of larvae. It is assumed that the polymorphism of larvae of the genus Aploparaksis results from the morphological adaptation to the development under arctic conditions.

Animals↗
PubMed1998

[Helminth diagnosis in pathologic anatomy].

Most publications devoted to diagnosis of helminths emphasize characteristic parasitological features. Histological feature are seldom described in detail. The purpose of this study was to propose a diagnostic method suitable for use by histologists who, unlike parasitologists, do not visualize the whole worm but rather pieces randomly scattered over a slide. It is relatively easy to distinguish helminths which have smooth muscle, no respiratory or circulatory system, and no coelom from arthropods which have striated muscle, both respiratory and circulatory systems, and coelom. At the adult stage, roundworms or nemathelminths present an external cuticle that may have patterned markings. The visceral cavity is empty. Adults can dwell either in the intestine in which case they are oviparous (oxyuris, ascaris, Ancylostoma, Strongyloides stercoralis, Trichuris...) or in tissue in which case they are viviparous (filaria). Larva of some species can be found in tissues. Adult tape-worms are devoid of cuticle and have a mesenchymatous visceral cavity. Cestodes which are segmented and have no digestive tract (taenias) are readily distinguishable from trematodes which are not segmented and have a digestive tract (faciolasis) Some cestodes unable thrive in man can cause cyst formation (hydatidosis, sparganosis, cysticercosis, coenurosis). On the basis of symptoms and histological features, it is usually possible to diagnose the genus and even the species of the offending helminth provided that the parasite has not been excessively damaged and that a sufficient number of sections are available.

Animals↗
PubMed2005

Microtriches of tetraphyllidean metacestodes from Western Mediterranean striped dolphins (Stenella coeruleoalba).

The tegumental structures of two types of tetraphyllidean plerocercoids and two types of merocercoids (Phyllobothrium delphini and Monorygma grimaldii) from Mediterranean striped dolphins, Stenella coeruleoalba, are described for the first time using scanning electron microscopy. The tegument of all of the specimens was fully covered with microtriches. Four basic types were found: filitriches, blade-like spinitriches of different sizes and shapes, cone-shaped spinitriches (with two parallel small projections of equal length at the apex), and crowned cylindrical spinitriches (with 6-7 small papillae forming a crown at the apex); the two latter types are newly described. The two types of plerocercoids had a similar morphology and distribution of microtriches; in addition, cilium-like projections appeared interspersed among the microtriches on the apical sucker, accessory suckers, and distal bothridial loculus. Merocercoids exhibited a greater variety of tegumental structures, especially on the distal bothridial loculus. Both merocercoid types had regularly spaced papillae or "buttons" on the accessory suckers and the distal bothridial loculus that were composed of a central cilium-like projection surrounded by numerous filitriches. However, crowned cylindrical spinitriches were specific to P. delphini and cone-shaped spinitriches were specific to M. grimaldii. Differences in the morphology and distribution of scolex microtriches of adult cestodes have been considered useful for species identification. A previous molecular study has suggested that P. delphini and M. grimaldii are actually different congeneric species. Our study has shown that significant differences in the morphology and distribution of microtriches occur between these species at the merocercoid stage.

Animals↗
PubMed1977

Cerebral coenurosis. Report of a case with arteritis.

A case of the unusual clinical condition of cerebral coenurosis, the unique parasitic disease that is localized only in the CNS, is reported. The patient had repeated attacks of transient hemiparesis due to intracranial arteritis which was demonstrated by several angiographic studies. The CSF showed a discreet lymphocytosis and increased immunoglobulins. This inflammatory reaction which preceeded the manifestations of the intracranial mass can be explained by the parasitic foreign bodies, the liberation of somatic and metabolic parasitic toxins and the immunological reaction of the organism. The arteritis of the basal intracranial vessels was probably secondary to the inflammatory reaction of the leptomeninges. In presence of the rare association of meningovascular disease and an expanding intracranial lesion a parasitic condition due to a larval stage of Cestodes (Hydatidosis, Cysticercosis, Coenurosis) should be always considered.

Adult↗
PubMed1981

Circulating antigens in infections of mice by tetrathyridia of Mesocestoides corti Hoeppli, 1925.

Two circulating antigens were detected in the serum of ICR/Timco female mice infected intraperitonealy with tetrathyridia of the cestode Mesocestoides corti Hoeppli, 1925. One circulating antigen appeared by day 2 postinfection (p.i.) and remained in all mice until at least 90 days p.i. A second antigen appeared in the serum on day 14 p.i. and disappeared from all mice by day 28 p.i. Infected mouse serum also contained antibodies against one secretory/excretory antigen and two antigens in crude homogenate, as judged by double diffusion in two dimensions (Ouchterlony). Immune deposits were observed in the kidney tissue of Rockland mice by transmission electron microscopy, and their identity as products of tetrathyridia was confirmed by immunofluorescence. Further studies showed that the main antibody subclass associated with the mesangial immune deposits was 7S gamma l, and that other subclasses of IgG and IgM were not involved. Antigen was found in the proximal renal tubules of infected mice, as demonstrated by fluorescein-labeled IgG fraction of rabbit antitetrathyridia secretory/excretory antigen antisera. The presence of tetrathyridia antigen in the urine of infected mice was confirmed using the Ouchterlony technique.

Animals↗
PubMed1992

A double surface membrane in plerocercoids of Ligula intestinalis (Cestoda: Pseudophyllidea).

The tegument of Ligula intestinalis plerocercoids is delimited by a membrane complex that in electron microscopy appears heptalaminate. We suggest that the plerocercoids are covered by two closely apposed lipid bilayers. Double membranes, which are well known in schistosomes, are thus not a unique feature of blood parasitic Digenea but could be documented for the first time in a cestode species that lives in the peritoneal cavity of its host. The surface-membrane complex of plerocercoids was lost for the most part after conventional preparation for electron microscopy but could be completely retained by improved fixation using osmium tetroxide plus potassium ferrocyanide. Furthermore, one type of vesicle in the tegumental syncytium of plerocercoids has been found to be enclosed by at least two membranes, which might indicate that these vesicles contribute to the renewal of the surface-membrane complex. Adult Ligula intestinalis removed from the gut of the final host Anas platyrhnychos or obtained by in vitro transformation exhibited a single surface membrane and lacked double membrane vesicles. The elongate electron-dense caps of the microtriches of plerocercoids were replaced by short caps in the course of worm maturation. Thus, the tegumental surface of this parasite is fundamentally altered following the change in its environment from the peritoneal cavity of the intermediate host to the intestine of the final host.

Animals↗
PubMed1989

Observations on the lipids of Oochoristica agamae (Cestoda).

An investigation of the lipids of Oochoristica agamae, an anoplocephalid cestode of the Agama lizard, was undertaken. Total lipids of the parasite accounted for 8.4% of the fresh weight; neutral lipids comprised 82.98% of the total, glycolipids, 5.01%, and phospholipids, 12.03%. The major lipid classes in O. agamae include triglycerides, cholesterol, phosphatidyl choline, and phosphatidyl ethanolamine. The 16- and 18-carbon fatty acids were predominant in the parasite. Hexadecenoic acid, usually found at low concentrations in the lipids of helminth parasites, was the most abundant of the 16-carbon fatty acids of O. agamae (notably in the neutral lipid fraction). Although octadecatrienoic acid occurred only in trace amounts in the intestinal contents of the host, significant amounts of this fatty acid were detected in the parasite. A lack of 20-carbon fatty acids was determined in the lipids of the host's intestinal contents and the neutral lipid fraction of the parasite. O. agamae is suspected to be capable of modifying fatty acids obtained from dietary sources by chain elongation.

Animals↗
PubMed1979

Chemotherapeutic effects of 4-isothiocyanato-4'-nitrodiphenylamine (C9333-Go/CGP 4540) on infections with Nematospiroides dubius, Hymenolepis diminuta, Hymenolepis nana and Spirometra mansonoides.

4-Isothiocyanato-4'-nitrodiphenylamine possessed anthelmintic activity against Nippostrongylus dubius and Hymenolepis nana in mice and H. diminuta in rats as determined by both egg counts and recovery of parasites at autopsy. No activity was detected against the cestode. Spirometra mansonoides, in cats.

Aniline Compounds↗
PubMed2000

Otobothrium cysticum (Cestoda: Trypanorhyncha) from the muscle of butterfishes (Stromateidae).

On the basis of the tentacular armature, surface ultrastructure, and morphological measurements of plerocerci obtained from the musculature of butterfishes (Stromateidae), we corroborate an earlier proposal that Otobothrium crenacolle, a commonly reported trypanorhynch cestode from the northwestern Atlantic coast, is a junior synonym of O. cysticum. This action exemplifies at least an Atlantic Ocean and Indian Ocean distribution for O. cysticum. The infection in commercially important butterfishes shows that an otobothriid trypanorhynch may heavily infect fish flesh and influence the market value of some fish species yet also be restricted to the body cavity of other fish intermediate hosts. Infections of O. cysticum in the flesh of Peprilus burti (Gulf butterfish) and P. alepidotus (harvestfish) in the Gulf of Mexico has varied annually since 1970, with samples ranging in prevalence between 20% and 100% and in mean intensity between 1 and 3,500 or more plerocerci per fish. Comparative infections in P. burti from the Gulf of Mexico and P. triacanthus (butterfish) from the Atlantic Ocean demonstrate a present geographic difference in infections. The prevalence and mean intensity in 4 collections of butterfishes ranged from 9% to 98% of the fish and from 1 to 678 plerocerci in a subsample of tissue, respectively, with prevalent and heavy infections being observed in the Gulf of Mexico fish and relatively few individuals being infected with few worms in the Atlantic fish. A slight host response in the butterfishes involving some fatty infiltration and inflammatory infiltration was associated with the metacestode. In some larger fish, encapsulations were yellow, and in a few cases, worms had degenerated. This finding and an increase in intensity with fish weight suggest a continual accumulation of the worms in association with little host resistance.

Animals↗
PubMed2003

A general survey of the helminth parasites of fish from inland waters in the Fayoum Governorate, Egypt.

During the present investigation, 450 fishes belonging to seven genera and seven species were examined for helminth parasites. Of these, 216 fishes (48%) were found to harbour Acanthocephala (14%), cestodes (16.22%), Digenea (10.66%), Monogenea (1.77%), or nematodes (6.22%). The species richness and intensity of infections are given. Results summarized from nine studies on the helminth parasites of fish from inland waters are presented. The incidence of infection is reported and compared in host/parasite lists.

Acanthocephala↗
PubMed2003

Canine echinococcosis in northern Jordan: increased prevalence and dominance of sheep/dog strain.

A total of 112 stray and semi-stray dogs (Canis familiaris) from four different geographical areas in northern and middle Jordan were necropsied to evaluate the prevalence and intensity of intestinal helminthiasis. Of these, 33 dogs (29.5%) were infected with Echinococcus granulosus and 61 (54.5%) with other Taenia species. Other cestodes found included Dipylidium caninum in 36 dogs (32.1%), Diplopylidium in 6 dogs (5.4%), Mesocestoides sp. in 3 dogs (2.7%) and Joyuexiella in 1 dog (0.9%). Toxocara nematodes were found in 10 dogs (9.2%) and only 1 dog was positive for acanthocephalans. Among the dogs infected with E. granulosus, 8 dogs (24.2%) had a worm load higher than 1,000 worms. The ratio of infected male to female dogs was 1.9:1.0. Strain analysis of E. granulosus using random primers revealed the dominance of the G1 strain (sheep/dog strain) in the region. Only one dog harbored another E. granulosus strain, which resembled the G4 strain pattern.

Animals↗
PubMed2004

The phylogeny of diphyllobothriid tapeworms (Cestoda: Pseudophyllidea) based on ITS-2 rDNA sequences.

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.

Animals↗