Cercariae
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Notocotylus attenuatus (Digenea: Notocotylidae) is a monostome fluke parasitizing the intestinal caeca of waterfowl that uses an injection apparatus to infect its intermediate snail host. Morphology of the invading larva (a sporocyst), and the intramolluscan larval development of this fluke have not been characterized extensively. In this study, experimental infections of Lymnaea stagnalis using N. attenuatus eggs resulted in the development of sporocysts containing one germ ball or mother redia between 12 and 21 days post exposure (p.e.) within the hepatopancreas. Independent mother rediae and developing daughter rediae were present between day 25 and day 42 p.e. Cercariae, within the body of rediae, were detected 42 days p.e. The development of daughter rediae and cercariae started posteriorly in the body of parent redia and these larvae migrated anteriorly during development towards the birth pore. A cercaria was also observed emerging from the birth pore and released cercariae maturated further within the snail hepatopancreas prior to leaving the snail. The intramolluscan development was completed 45 days p.e. when the first fully formed cercariae were shed into the outer environment. These data detail the fascinating post-embryonic development of N. attenuatus and highlight the intricate nature of larval transitions within its snail host.
In the present study, we review the known zoogonid cercariae, summarise their life-cycles and first intermediate host distributions, and present a new cercaria, Cercaria capricornia XI (Digenea: Zoogonidae), which was found in one of three nassariid gastropods, Nassarius olivaceus (Bruguière), surveyed in the intertidal zone in the Capricornia region of Central Queensland, Australia. Morphological data and molecular analysis of the ITS2 rDNA region support placement of this cercaria in the family Zoogonidae but do not allow any further resolution of its identity. There are now fifteen cercariae described as belonging to the Zoogonidae; thirteen of these, including the present species, infect neogastropods as first intermediate hosts and two use vetigastropods. This study reinforces the pattern that the Nassariidae is by far the most commonly reported family for the Zoogonidae. Given its richness we predict that the Nassariidae will prove to harbour many more zoogonid species.
- MeSH
- cerkárie anatomie a histologie klasifikace genetika izolace a purifikace MeSH
- druhová specificita MeSH
- ekosystém MeSH
- fylogeneze MeSH
- interakce hostitele a parazita MeSH
- mezerníky ribozomální DNA genetika MeSH
- plži parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Queensland MeSH
Microcercous cercariae possess a very short tail and are produced by digenean species of several families including medically important species, such as members of the genera Paragonimus Braun, 1899, Nanophyetus Chapin, 1927 and Troglotrema Odhner, 1914. During our survey of cercariae of Paragonimus spp. in Vietnam, we found microcercous cercariae from ten (0.29%) out of 3,400 snails of Triculinae gen. sp. 2. They were morphologically and molecularly analysed for species identification. The molecular analysis, based on ITS2 sequences, revealed two distinct species: four specimens were identical to Paragonimus proliferus Hsia et Chen, 1964 (Paragonimidae Dollfus, 1939), and the other six specimens were closest to members of the family Troglotrematidae Odhner, 1914 and were temporarily named Troglotrematidae gen. sp. Morphologically, cercariae of the two species found in this study are similar to each other in their gross characteristics but can be distinguished from one another by subtle morphological details. The cercaria of P. proliferus has an I-shaped excretory bladder and does not have mucous gland cells. In contrast, that of Troglotrematidae gen. sp. has a Y-shaped excretory bladder and mucous gland cells. Besides, the redia of P. proliferus is elongate with a short intestine and contains 5-6 cercariae whereas that of Troglotrematidae gen. sp. is more round with a longer intestine and harbours 3-4 cercariae. Our results have shown the importance of the shape of the excretory bladder and the presence/absence of mucous gland cells of the cercaria as well as the shape and size of the redia, and its intestinal length as valuable taxonomic characters of intramolluscan trematode larvae. In addition, the finding of similar microcercous cercariae of different species in the same snail species suggests that careful attention to morphological details is required in the differentiation of Paragonimus cercariae and those of closely related species.
- MeSH
- cerkárie klasifikace genetika růst a vývoj izolace a purifikace MeSH
- DNA helmintů analýza MeSH
- fylogeneze MeSH
- hlemýždi parazitologie MeSH
- mezerníky ribozomální DNA analýza MeSH
- Paragonimus klasifikace růst a vývoj izolace a purifikace MeSH
- sekvenční analýza RNA MeSH
- Troglotrematidae klasifikace genetika růst a vývoj izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Vietnam MeSH
During late summer in 1995 to 1997, repeated outbreaks of maculopapular skin eruptions were noted on the legs of children after wading in the pond in the Family Park in Laugardalur, Reykjavik, Iceland. Clinical symptoms developing on the legs resembled those of cercarial dermatitis. An examination of Lymnaea peregra snails from this pond and from the adjacent Lake Tjornin resulted in detection of previously undescribed schistosome cercariae. This is the first report of schistosomes in Iceland and also the most northern occurrence of these parasites in Europe.
- MeSH
- dermatitida * parazitologie MeSH
- dítě MeSH
- lidé MeSH
- Lymnaea parazitologie MeSH
- myši inbrední ICR MeSH
- myši MeSH
- parazitární onemocnění kůže * parazitologie patologie MeSH
- plavání * MeSH
- pruritus * parazitologie MeSH
- Schistosoma anatomie a histologie izolace a purifikace MeSH
- schistosomóza * parazitologie patologie MeSH
- zvířata MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Geografické názvy
- Island MeSH
Bird schistosomes and cases of human cercarial dermatitis occur worldwide, but the number of cases is not monitored. Experiments with two schistosomes, namely Trichobilharzia szidati and T. regenti, show that they possess potent tools to penetration bird and mammalian skin, as well as exhibit species-specific migration patterns within vertebrate bodies. Therefore, the infections may affect different organs/tissues e.g. lungs or spinal cord. In this minireview, the adaptations and pathogenic effects of bird schistosomes in experimental mammals are discussed, and some ideas/hypotheses on risks to humans from exposure to bird schistosome cercariae are expressed.
- MeSH
- druhová specificita MeSH
- financování organizované MeSH
- fyziologická adaptace MeSH
- infekce červy třídy Trematoda parazitologie veterinární MeSH
- lidé MeSH
- Lymnaea parazitologie MeSH
- nemoci míchy parazitologie veterinární MeSH
- parazitární onemocnění plic parazitologie veterinární MeSH
- ptáci MeSH
- Schistosomatidae fyziologie patogenita MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
