trematode egg
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The vitellogenesis of the trematode Aspidogaster limacoides (Aspidogastrea: Aspidogastridae), a parasite of cyprinid fishes, is described here using transmission electron microscopy. Four different stages of vitellocytes are differentiated: immature vitellocytes, early maturing vitellocytes, advanced maturing vitellocytes and mature vitellocytes. The process follows the same general pattern already described in other free-living neoophorans and parasitic flatworms (i.e. Trematoda, Monogenea and Cestoda): differentiation into mature vitelline cells involves the development of mitochondria, granular endoplasmic reticulum, Golgi complexes, lipid droplets and shell-globules. Mature vitellocytes of A. limacoides are composed of numerous shell-globule clusters, few lipid droplets and glycogen granules. They differ from those of another aspidogastrean Rugogaster hydrolagi in that they possess numerous globules tightly packed and by the presence of only one type of vitelline material. The interstitial tissue of vitelline follicles of A. limacoides contains a peripheral nucleus and long cytoplasmic projections extending between vitelline cells. Since aspidogastreans are considered as an archaic group of parasitic flatworms and thus have a strategic phylogenetic position, future works needs to pay special attention to the ultrastructural and chemical composition of mature vitellocytes within this basal group of trematodes.
- MeSH
- Cyprinidae parazitologie MeSH
- infekce červy třídy Trematoda parazitologie veterinární MeSH
- nemoci ryb parazitologie MeSH
- ovum fyziologie ultrastruktura MeSH
- transmisní elektronová mikroskopie MeSH
- Trematoda klasifikace růst a vývoj metabolismus ultrastruktura MeSH
- vitelogeneze fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We have explored a large body of novel data focusing on small-scale temporal and spatial patterns in the composition and structure of larval trematode communities in Lymnaea stagnalis (L.) from a typical Central European agricultural landscape. The 5 eutrophic fishponds studied provide excellent environments for the development of species-rich and abundant trematode communities. Nine prevalent species were consistently present in component communities, but had differential contribution to the parasite flow in the 5 ponds resulting in significant contrasting patterns of community similarity and the prevalence of the 3 major transmission guilds driving this similarity. Component communities split into 2 groups: (i) those from the large pond dominated by anatid and larid generalists with active miracidial transmission; and (ii) those from the smaller ponds dominated by 2 plagiorchioideans infecting snails via egg ingestion. We put forward 3 hypotheses for the remarkable differences in larval trematode flow in the similar and closely located eutrophic ponds: (i) species-specific differences in parasite colonization potential displayed by an 'active-passive' dichotomy in miracidial transmission strategies of the species; (ii) top-down effects of pond context on transmission pathways of the trematodes; and (iii) competition as an important mechanism in eutrophic environments with a bottom-up effect on component community structure.
- MeSH
- biodiverzita * MeSH
- ekosystém * MeSH
- hlemýždi parazitologie MeSH
- interakce hostitele a parazita MeSH
- roční období MeSH
- rybníky parazitologie MeSH
- stadia vývoje MeSH
- Trematoda fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Polystomatid monogeneans have a wide diversity of life cycles correlated with the varied ecology and behaviour of their aquatic vertebrate hosts. Typically, transmission involves a swimming infective larva but most hosts are amphibious and invasion is interrupted when hosts leave water. A key life cycle adaptation involves a uterus that, in the most specialised cases, may contain several hundred fully-developed larvae prepared for instant host-to-host transmission. By contrast, one subfamily of the Polystomatidae - the Polystomoidinae, specific to chelonians (freshwater turtles) - has a simplified reproductive system without a uterus. Recently, Polystomoides nelsoni Du Preez et Van Rooyen, 2015 has been described with a uterus containing multiple eggs. The present study explores the exceptional interest of this parasite - for the functional biology of egg production, for the evolution of a reproductive system unique amongst ca 60 species in the subfamily, and for systematic relationships. A new genus is proposed, Uteropolystomoides gen. n., separate from the four currently-recognised genera Polystomoides Ward, 1917, Uropolystomoides Tinsley et Tinsley, 2016, Neopolystoma Price, 1939 and Polystomoidella Price, 1939 which lack a uterus. In addition, U. nelsoni (Du Preez et Van Rooyen, 2015) comb. n. has a suite of distinctive copulatory stuctures: a massive genital bulb with an exceptionally large number of very long genital spines and hyper-development of the vaginal openings. These characters set U. nelsoni apart from all other polystomoidines worldwide except Polystomoides multifalx Stunkard, 1924 and P. stunkardi Harwood, 1931. Missing data for these latter species preclude definitive assessment of inter-relationships but the distinguishing characters of U. nelsoni, especially the unique occurrence of the uterus, suggest a novel evolutionary pathway isolated from other lineages of polystomatids infecting chelonians.
- MeSH
- biologická evoluce MeSH
- infekce červy třídy Trematoda parazitologie veterinární MeSH
- ovarium anatomie a histologie MeSH
- počet parazitárních vajíček veterinární MeSH
- rozmnožování MeSH
- sladká voda parazitologie MeSH
- Trematoda anatomie a histologie klasifikace MeSH
- uterus anatomie a histologie MeSH
- želvy parazitologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Between March 2012 and April 2014, we performed post-mortem parasitological examinations of 11 Eurasian beavers (Castor fiber Linnaeus, 1758) from the basins of four main rivers (Dyje, Labe, Morava, Vltava) in the Czech Republic. The cause of death of five adult animals was unknown, three adult animals died after being hit by cars, while one young and one adult as a result of serious injuries and one juvenile male drowned. The trematode Stichorchis subtriquetrus (Rudolphi, 1814) Lühe, 1909 was only found in the caecum body and caecum apex of nine beavers (82%), with no significant differences in parasite intensity among beavers. The highest number of trematodes (271) occurred in an adult female in July 2013; while a range of 1-57 individuals were found in other positive beavers. S. subtriquetrus size in both parts of the caecum was 11.0-17.0 × 5.5-8.0 mm (mean 14.3 × 6.9 mm). Results demonstrated that for the optimal detection of eggs, it was necessary to examine at least 10 g of faeces with a new modified method of sedimentation. The size range of 30 eggs was 157.1-182.5 × 99.3-109.8 μm (mean 168.0 × 104.4 μm). There were no differences in prevalence and seasonal occurrence of S. subtriquetrus between male and female beavers. We did not find any other intestinal endoparasites or tissue parasites (Sarcocystis spp., Trichinella spp.).
- MeSH
- hlodavci parazitologie MeSH
- infekce červy třídy Trematoda epidemiologie parazitologie veterinární MeSH
- Trematoda klasifikace izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
An expedition was undertaken to French Guiana in search of amphibian parasites. Of the 23 anuran species collected and screened for polystomes, the toad Rhinella margaritifera (Laurenti) was the sole species found to be infected with a polystome, namely Wetapolystoma almae Gray, 1983. Of the two caecilian species collected, a new species of Nanopolystoma du Preez, Huyse et Wilkinson, 2008 was discovered from the urinary bladder of the aquatic caecilian Typhlonectes compressicauda (Duméril et Bibron). The small size of the mature worm, two non-diverticulated caeca of equal length that are non-confluent posteriorly, vitelline follicles in two dense lateral fields, a single follicular testis in the middle of the body, small ovary and a single operculated egg in utero, vaginae present and the caecilian host allowed the identification of the specimen as Nanopolystoma. Larger body size, hamulus length, egg diameter and occurrence in the caecilian family Typhlonectidae distinguishes the new species from the two other known polystomes in Nanopolystoma; thus, the description of Nanopolystoma tinsleyi sp. n. is provided within this paper.
- MeSH
- biodiverzita MeSH
- druhová specificita MeSH
- infekce červy třídy Trematoda epidemiologie veterinární MeSH
- obojživelníci parazitologie MeSH
- ploštěnci anatomie a histologie klasifikace MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Francouzská Guyana MeSH
Trematodes of the order Diplostomida are well known as serious pathogens of man, and both farm and wild animals; members of the genus Schistosoma (Schistosomatidae) are responsible for human schistosomosis (schistosomiasis) affecting more than 200 million people in tropical and subtropical countries, and infections of mammals and birds by animal schistosomes are of great veterinary importance. The order Diplostomida is also rich in species parasitizing other major taxa of vertebrates. The "Aporocotylidae" sensu lato are pathogenic in fish, "Spirorchiidae" sensu lato in reptiles. All these flukes have two-host life cycles, with asexually reproducing larvae usually in mollusks and occasionally in annelids, and adults usually live in the blood vessels of their vertebrate hosts. Pathology is frequently associated with inflammatory reactions to eggs trapped in various tissues/organs. On the other hand, the representatives of Diplostomidae and Strigeidae have three- or four-host life cycles in which vertebrates often serve not only as definitive but also as intermediate or paratenic hosts. Pathology is usually associated with migration of metacercariae and mesocercariae within the host tissues. The impact of these trematode infections on both farm and wild animals may be significant.
The functional ultrastructure and embryonic development of miracidia in naturally released eggs of the trematode Cardiocephaloides longicollis were studied using light and transmission electron microscopy. This species has operculated eggs and embryogenesis occurs in the marine environment before an actively infecting ciliated miracidium hatches. Six different developmental stages were identified. The lack of pores in the eggshell indicates its impermeability and the miracidium's dependency on glycogen nutritive reserves, contained in numerous vitellocytes in early embryos. As the development advances, these merge into larger vitelline vacuoles that encircle the miracidium and may aid its hatching. Tissue and primary organ differentiation were observed in advanced stages, i.e., terebratorium, glands, cerebral ganglion, peripheral sensory endings, and eyespots. The anterior part of the body contains a single apical and paired lateral glands, as well as two types of sensory endings, which permit location, adhesion, and penetration of the host. No previous studies describe the embryonic development and ultrastructure of miracidia in strigeids, however, some of the structural features shared with other, well described species with unknown life cycles are emphasised. This study highlights that ultrastructural data have to be interpreted in relation to parasite biology to understand the structural requirements of specific parasite strategies.
Parasitological investigations carried out on birds in Iceland and France highlight the presence of four species of avian schistosomes from greylag geese (Anser anser L.): the european nasal species Trichobilharzia regenti and three visceral species, among which an unknown species isolated from blood vessels of the large intestine and liver. Morphological and molecular analyzes of different parasite stages (eggs, adults) revealed new species of Trichobilharzia genus – Trichobilharzia anseri sp. nov. Studies on host-parasite relationship under natural conditions, showed that the life-cycle includes the snail Radix balthica (syn. R. peregra) as intermediate host. The cercariae, already isolated in Iceland from two ponds of the Reykjavik capital area – the Family park and Tjörnin Lake – are the same as those isolated in 1999 by Kolářová et al. during the first study on Icelandic parasitic agents of cercarial dermatitis.
- MeSH
- DNA helmintů genetika MeSH
- fylogeneze MeSH
- hlemýždi parazitologie MeSH
- husy parazitologie MeSH
- infekce červy třídy Trematoda parazitologie veterinární MeSH
- infekce přenášené vektorem MeSH
- nemoci drůbeže parazitologie MeSH
- ovum ultrastruktura MeSH
- Schistosomatidae genetika izolace a purifikace ultrastruktura MeSH
- sekvenční analýza DNA MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Francie MeSH
- Island MeSH
Trematodes of the order Diplostomida are well known as serious pathogens of man, and both farm and wild animals; members of the genus Schistosoma (Schistosomatidae) are responsible for human schistosomosis affecting more than 200 million people in tropical and subtropical countries, infections of mammals and birds by animal schistosomes are of great veterinary importance. The order Diplostomida is also rich in species parasitizing other major taxa of vertebrates. The Aporocotylidae are pathogenic in fish, Spirorchiidae in reptiles. All these flukes have two-host life cycles, with asexually reproducing larvae usually in molluscs and occasionally in annelids, and adults usually live in the blood vessels of their vertebrate hosts. Pathology is frequently associated with inflammatory reactions to eggs trapped in various tissues/organs. On the other hand, the representatives of Diplostomidae and Strigeidae have three- or four-host life cycles in which vertebrates often serve not only as definitive, but also as intermediate or paratenic hosts. Pathology is usually associated with migration of metacercariae and mesocercariae within the host tissues. The impact of these trematode infections on both farm and wild animals may be significant.
- MeSH
- infekce červy třídy Trematoda * parazitologie přenos MeSH
- interakce hostitele a parazita MeSH
- lidé MeSH
- měkkýši parazitologie MeSH
- nemoci ryb parazitologie MeSH
- ryby parazitologie MeSH
- stadia vývoje MeSH
- Trematoda * fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Seven species of fishes, Catostomus commersonii (Lacépède), Etheostoma nigrum Rafinesque, Micropterus dolomieu Lacépède, Notemigonus crysoleucas (Mitchill), Notropis hudsonius (Clinton), Perca flavescens (Mitchill), and Percina caprodes (Rafinesque) from the St. Lawrence River, Quebec, Canada, were found infected with progenetic specimens of Neochasmus spp. in the orbits and/or the body musculature. Worms displayed varying degrees of maturation. Eggs occupied the entirety of the worm in late stages of development and persisted as distinct clusters in situ after worm death. Populations of parasites were studied monthly in E. nigrum from one site between May and October in order to follow parasite recruitment, development and maturation. Recruitment of parasites was observed in young-of-the-year fish primarily in July and continued through October. Worms matured rapidly, displaying egg production within a month. Later developmental stages, in which eggs occupied most of the worm, and clusters of eggs became abundant by September. Infections in overwintered fish collected in May consisted mainly of worms in early stages of egg production and of clusters of eggs. When hatched artificially, eggs from the clusters released viable miracidia, indicating that they survive beyond the lifespan of the adult worm. It is suggested that progenesis is a fixed characteristic of the life cycle of these species, that egg dispersal requires the death of the host and that it is facilitated by predation. All prior records of Neochasmus spp. are examined, leading us to conclude that the role of the putative definitive host (primarily basses) has been reduced to that of a dispersal agent. Current hypotheses concerning the evolution and maintenance of progenesis are considered, but it is concluded that they do not apply to this host-parasite system.
- MeSH
- infekce červy třídy Trematoda epidemiologie parazitologie veterinární MeSH
- nemoci ryb epidemiologie parazitologie MeSH
- oči parazitologie MeSH
- prevalence MeSH
- řeky MeSH
- roční období MeSH
- ryby MeSH
- stadia vývoje MeSH
- střeva parazitologie MeSH
- svaly parazitologie MeSH
- Trematoda růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- provincie Québec MeSH
