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-Diplostomum pseudospathaceum (A, B); Australapatemon burti (C, D); Australapatemon minor (E, F); Tylodelphys clavata (G, H); Cotylurus cornutus (I); A, C, E, G, I-detail of body, scale bars: A, C, E, I-50 µm, G-100 µm; B, D, F, H-whole cercaria, scale bars: B, H-100 µm, D, F-50 µm.
Source publication
A survey of cercariae and metacercariae (Trematoda, Digenea) from the great pond snail (Lymnaea stagnalis) in Central Europe (Austria, Czech Republic, South-East Germany, Poland and Slovak Republic) is presented, based on a study of 3,628 snails examined from 1998 to 2005. A total of 953 (26.3%) L. stagnalis were infected with 24 trematode species...
Contexts in source publication
Context 1
... Grabda-Kazubska (1969), Nezvalová (1970), Gelnar (1980), Dimitrov et al. (1989) (Fig. 5B, C) Cercariae larger; stylet with anterior thickening (see Fig. 5E Two pairs of large postacetabular penetration glands; anterior organ with large conspicuous spines; caeca long, reach to body end; flame cell formula 2 [(1 + 1 + 1) + (1 + 1 + 1) + (2) Fig. 2A, B) Four pairs of small, poorly visible postaceta- bular penetration glands; anterior organ with fine spines; caeca short, reach to posterior end of ventral sucker; flame cell formula 2 [2 + (2 + 2 + (1) (Fig. 2C, D) Whole body spinose ............................... Australapatemon minor (Fig. 2E, F Metacercaria small (about 140 mm in ...
Context 2
... anterior organ with large conspicuous spines; caeca long, reach to body end; flame cell formula 2 [(1 + 1 + 1) + (1 + 1 + 1) + (2) Fig. 2A, B) Four pairs of small, poorly visible postaceta- bular penetration glands; anterior organ with fine spines; caeca short, reach to posterior end of ventral sucker; flame cell formula 2 [2 + (2 + 2 + (1) (Fig. 2C, D) Whole body spinose ............................... Australapatemon minor (Fig. 2E, F Metacercaria small (about 140 mm in diameter) .... 5 4 Collar of excysted metacercaria narrower than long body, with 35 spines of same length; three spherical anlagen of reproductive organs ... (Fig. 6C) Cercaria with 45 collar spines; excretory ...
Context 3
... cell formula 2 [(1 + 1 + 1) + (1 + 1 + 1) + (2) Fig. 2A, B) Four pairs of small, poorly visible postaceta- bular penetration glands; anterior organ with fine spines; caeca short, reach to posterior end of ventral sucker; flame cell formula 2 [2 + (2 + 2 + (1) (Fig. 2C, D) Whole body spinose ............................... Australapatemon minor (Fig. 2E, F Metacercaria small (about 140 mm in diameter) .... 5 4 Collar of excysted metacercaria narrower than long body, with 35 spines of same length; three spherical anlagen of reproductive organs ... (Fig. 6C) Cercaria with 45 collar spines; excretory granules smaller ..... Echinoparyphium recurvatum (Fig. 6B) 6 Refractile granules in ...
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Citations
... Isthmiophora melis develops with the involvement of the gastropod Lymnaea stagnalis (Linnaeus, 1758). The second intermediate hosts of this parasite are amphibians and freshwater fish [183][184][185]. ...
Insectivores (Eulypotiphla) are a substantial component of Russian forest ecosystems. The parasites of these animals also form an important part of natural biocenoses and act as one of the factors in the formation of biodiversity. The Mordovia Nature Reserve and National Park “Smolny” are large, forested areas located in the center of European Russia. We studied the helminth fauna of insectivores in these protected areas in 2018–2022. In total, using the method of complete helminthological necropsy, we examined 478 individuals of shrews, moles, and hedgehogs and recorded 34 species of parasitic worms, i.e., 8 trematode, 7 cestode, 1 acanthocephalan, and 18 nematode species. The most diverse helminth fauna was found in Sorex araneus (22 species). The composition of helminths in S. isodon (12), Neomys fodiens (9), Sorex minutus, and Erinaceus roumanicus (8 species each) turned out to be less diverse. The lowest species diversity of helminths was observed in Neomys milleri (3) and Talpae europaea (2 species). Taking into account the newly obtained data, we conducted a review of the helminth diversity in shrews, hedgehogs, and moles in the Middle Volga region. According to our literature data, the helminth fauna of insectivores in this region consists of 52 species, including 14 cestodes, 13 trematodes, 22 nematodes, and 3 acanthocephalans. Most of them belong to the Palearctic faunal complex (36 species). The helminth fauna of insectivores in the studied protected areas was compared with the helminth fauna of micromammals in other areas of the Middle Volga region. Our comparative analysis showed a high and average degree of similarity in the helminth fauna within individual species and genera of Eulipotyphla.
... The snails infected with D. pseudospathaceum were kept at 4 °C until the start of the experiment to prevent cercariae shedding. Parasite species were initially identified using morphological criteria (Faltýnková et al., 2007). This identification was selectively verified by sequencing of the ITS1-5.8S-ITS2 ...
Polyclonal infections are widespread and provide evidence of facilitation, competition, and neutral interactions between parasite clones, even within the same host-parasite system. The outcome of co-infections is usually assessed by parasite infection intensities, while other important fitness-related traits, e.g. larval growth rates, are often ignored. We studied both infectivity and the growth rate of different clones of the common trematode Diplostomum pseudospathaceum in the fish host ( Salvelinus malma ) and tested how these fitness-related traits changed in double-clone infections compared to single-clone ones. We found that the growth rates of the parasite’s clones were more variable than their infectivity. The relationships of these D. pseudospathaceum traits with host mass were clone-specific. Some clones demonstrated higher infection intensities and growth rates in larger fish. It hints that specialization on different size groups of hosts may occur in this parasite species. In addition, we found positive density-dependent growth (Allee effect), rarely reported for parasites. Interestingly, it was observed only in mixed infections and we discuss the reasons for it. In double-clone infections, both evidence of facilitation and competition between D. pseudospathaceum clones were found. The outcome of co-infections varied not only between genotype combinations but also between tested traits. Clones either ‘cooperated’ when infecting the host or competed when growing. There were no clone pairs, in which interactions changed their type with time or were observed constantly during parasite development.
... In the laboratory, snails were placed individually in plastic beakers filled with lake water and left under a light source for at least 48 h to stimulate cercarial emergence. Snails shedding cercariae of Plagiorchis (identified to genus level using the key of Faltýnková et al. [47]) were then separated, live cercariae were photographed using a Diversity 2024, 16, 158 5 of 28 digital camera Promicam 3-5CP (Promicra, Prague, Czech Republic) attached to an Olympus BX51 light microscope (Olympus Optical Co., Ltd., Tokyo, Japan), and representative samples of cercariae were fixed in molecular-grade ethanol (Penta, Prague, Czech Republic). Several samples of cercariae were additionally fixed in a 'cold' (i.e., unheated) 4% formaldehyde solution (formalin) to obtain morphometric data. ...
... Penetration gland-cells large, asymmetric, in two groups of seven and eight on each side of body, antero-and postlateral to ventral sucker. Lipid droplets (also called spherical fat droplets, fat inclusions or refractile granules [40,47,87]) not numerous, small and medium-sized scattered throughout body parenchyma; small droplets form clusters in both oral (few present) and ventral suckers (more numerous). ...
Cercariae of Plagiorchis spp. are frequently reported in European freshwater snails, but their true diversity is difficult to estimate due to subtle differences in morphology. We molecularly characterized 67 isolates of Plagiorchis cercariae collected from four lymnaeid snail hosts, Ampullaceana balthica, Ampullaceana lagotis, Radix auricularia and Lymnaea stagnalis in freshwater ecosystems in the Czech Republic and Poland. Based on mitochondrial cox1 and nuclear 28S sequences, ten species or species-level lineages were identified, including the first molecular evidence of P. vespertilionis from snail hosts and two species-level lineages reported for the first time. Previously undescribed species and species-level lineages are characterized morphometrically. We confirm the overlapping spatial distribution of Plagiorchis spp. in their snail hosts from Central Europe with those from Western and sub-Arctic Europe. Our results increase the known diversity of Plagiorchis spp. in Europe to 25 species/lineages in snails, but further research is needed to establish links between life cycle stages and to assess the host specificity of these parasites.
... The predator-induced dilution of trematode cercariae was in our study represented by E. aconiatum, which is one of the most common echinostome species infecting the first intermediate hosts Lymnaea stagnalis (Linnaeus, 1758) (Gastropoda: Pulmonata) in European freshwater bodies (Faltýnková et al., 2007;Faltýnková & Haas, 2006;Loy & Haas, 2001;Marszewska et al., 2016Marszewska et al., , 2018Soldánová et al., 2011). Cercariae of this species are a suitable research model for observing complex ecological digenean interactions in benthic communities inhabiting shallow littoral waters . ...
... Secondly, the low specificity for the second intermediate molluscan host (Keeler & Huffman, 2009;Stanicka et al., 2020), in which cercariae transform into metacercariae awaiting for the ingestion by a definitive host, represents an increased transmission success compared to many other trematode taxa infecting a wide range of aquatic invertebrates (Galaktionov & Dobrovolskij, 2003). Lastly, the cercariae of E. aconiatum have a relatively large body size (500-600 μm) (Faltýnková et al., 2007), and predators are generally attracted to a larger prey as they may offer higher nutritional resources (Born-Torrijos et al., 2021;Catania et al., 2016;Orlofske et al., 2015). ...
1. Predation is considered one of the key drivers shaping the relationships between animals. There is increasing evidence that non-host aquatic taxa use free-living parasite stages as prey, including motile cercariae of digenean trematodes. However, species-specific predator differences in cercarial consumption are poorly understood, especially when invasive consumers are involved.
2. We used experimental approaches to investigate the possible predator-induced reduction in trematode-host encounters in freshwater benthic communities. Four gammarid species, two native European (Gammarus jazdzewskii and G. pulex) and two invasive Ponto-Caspian (Dikerogammarus villosus and Pontogammarus robust-oides), were selected as predators of echinostomatid cercariae (Echinoparyphium aconiatum).
3. We hypothesised that (i) all predators will prey on cercariae, but the amount of prey consumed will vary, the invaders will be more voracious than native species, and (ii) the effect of predator-induced dilution of cercariae will depend on the environmental condition, i.e., the presence of the natural target host (the planorbid snail Planorbarius corneus) and alternative food resource; the exposure of predators to these two basic environmental factors will reduce their consumption rates of cercariae.
4. The extent of the dilution effect caused by gammarids was highly predator species-dependent and also varied depending on experimental conditions. Overall, all gammarids preyed on cercariae and reduced infection levels in the target snail host, but the invaders were more efficient than the native species. Furthermore, decreased consumption rates of cercarial prey were observed in the presence of both the target snail hosts and alternative food resources, except for invasive P. robustoides consuming more cercariae when a snail host was present.
5. The observed differences among predators in the consumption of cercariae may be a result of complex interaction traits of parasites, predators and target hosts, such as different predatory behaviour of invasive and native amphipods, change in parasite behaviour in response to the presence/chemical signals of the target host and a predator-induced “ecology of fear” interfering with the dilution effect of parasites.
6. We provided evidence that gammarids can cause a significant reduction in parasite- host encounters. The high consumption rates, especially in the presence of easily available alternative food resources, emphasise the importance of free- living cercariae as an energy resource in aquatic food webs. The observed preda-tor differences in the consumption of cercariae are further evidence of the higher competitive ability of invasive species. Simultaneously, our results indicate that the appearance of new predators in the environment may interfere with estab-lished host- parasite interactions.
... (20). Morphometry of 20 cercariae of Echinostoma spp. was done. ...
Background:
Identification of the larval stages of Echinostoma spp. in freshwater snails is an essential guide to continue monitoring the possibility of their transmission and the potential of echinostomiasis in areas where trematodes are the primary agent of parasitic diseases. The aim of this study was investigate Echinostoma using morphological and molecular techniques.
Methods:
The study was conducted in Gilan and Mazandaran Provinces, northern Iran, from April 2019 to October 2021. Overall, 5300 freshwater snails were randomly collected and were identified using external shell morphology. Meanwhile, snails infected with trematodes were studied via shedding and dissecting methods. Larvae stages of Echinostoma were identified and the genomic DNA of the samples was extracted. The PCR amplification of the ITSI gene was carried out for 17 isolates and products were sequenced. Seven sequences were deposited in GenBank.
Results:
Totally, 3.5% of snails containing three species (Stagnicola sp., Radix sp. and Planorbis sp.) were infected with two types of cercaria, E. revolutum with 37 and Echinostoma sp. with 45 spines in the collar. Moreover, 35% of the snails were infected with Echinostoma spp. metacercaria. Phylogenetic analysis illustrated that isolates were included in two ITSI haplogroups.
Conclusion:
Results showed the potential hazard of a zoonotic parasite as Echinostoma in northern Iran. The potential of disease environmental relationship investigation and resource control optimization is necessary for effective disease prevention and health management.
... They have been found in a wide Section Editor: Xing-Quan Zhu * Janelle Laura J. Gacad ov56jgacad@ec.usp.ac.jp * Natalia I. Yurlova yurlova@ngs.ru range of hosts, namely freshwater pulmonate gastropods as first intermediate hosts (Frolova 1975;Belyakova 1981;Belyakova and Tarmakhanov 1985;Butorina and Sinebokova 1987;Faltýnková et al. 2007;Soldánová et al. 2010;Vodyanitskaya and Yurlova 2013;Rastyazhenko et al. 2015), and a broad spectrum of second intermediate hosts, such as aquatic insects and their larvae, freshwater fish, and crustaceans (Guk et al. 2007;Boyce et al. 2013;Soldánová et al. 2017;Kudlai et al. 2021;Ponomareva et al. 2022). These parasites are dispersed through their definitive hosts, including birds and mammals and rarely in amphibians and reptiles (Boyce et al. 2013;Greani et al. 2014). ...
Plagiorchis multiglandularis Semenov, 1927 is a common fluke of birds and mammals, with significant impacts on animals and also human health. However, the systematics of Plagiorchiidae remain ambiguous. In the present study, the complete mitochondrial (mt) genome of P. multiglandularis cercariae was sequenced and compared with other digeneans in the order Xiphidiata. The complete circular mt genome of P. multiglandularis was 14,228 bp in length. The mitogenome contains 12 protein-coding genes and 22 transfer RNA genes. The 3′ end of nad4L overlaps the 5′ end of nad4 by 40 bp, while the atp8 gene is absent. Twenty-one transfer RNA genes transcribe products with conventional cloverleaf structures, while one transfer RNA gene has unpaired D-arms. Comparative analysis with related digenean trematodes revealed that A + T content of mt genome of P. multiglandularis was significantly higher among all the xiphidiatan trematodes. Phylogenetic analyses demonstrated that Plagiorchiidae formed a monophyletic branch, in which Plagiorchiidae are more closely related to Paragonimidae than Prosthogonimidae. Our data enhanced the Plagiorchis mt genome database and provides molecular resources for further studies of Plagiorchiidae taxonomy, population genetics and systematics.
... One of the fascinating examples of perch-parasite interactions involves diplostomids (Diplostomidae, Trematoda). This fluke family is a widespread and species-rich trematode group infecting aquatic gastropods and fishes before reaching birds or fish-eating mammals as definitive hosts (Chappell, 1995;Faltýnková et al., 2007). Ocular infection generally causes visual disturbances or even blindness in affected fish, reducing its ability to forage and avoid predation, which benefits parasite transmission (Faltýnková et al., 2007;Gopko et al., 2017;Vivas Muñoz et al., 2019). ...
... This fluke family is a widespread and species-rich trematode group infecting aquatic gastropods and fishes before reaching birds or fish-eating mammals as definitive hosts (Chappell, 1995;Faltýnková et al., 2007). Ocular infection generally causes visual disturbances or even blindness in affected fish, reducing its ability to forage and avoid predation, which benefits parasite transmission (Faltýnková et al., 2007;Gopko et al., 2017;Vivas Muñoz et al., 2019). Perch is infected by several diplostomid species and often has high infection prevalence as well as parasite load making it a popular subject for host-parasite investigations (Höglund & Thulin, 1990;Karvonen et al., 2009;Rellstab et al., 2011;Sobecka & Słomińska, 2007). ...
Eurasian perch Perca fluviatilis has been a popular model species for decades in the fields of aquatic ecology, community dynamics, behaviour, physiology and ecotoxicology. Yet, despite extensive research, the progress of integrating genomic perspective into existing ecological knowledge in perch has been relatively modest. Meanwhile, the emergence of high-throughput sequencing technologies has completely changed the methods for genetic variation assessment and conducting biodiversity and evolutionary research. During the last 5 years, three genome assemblies of P. fluviatilis have been generated, allowing substantial advancement of our understanding of the interactions between ecological and evolutionary processes at the whole-genome level. We review the past progress, current status and potential future impact of the genomic resources and tools for ecological research in Eurasian perch focusing on the utility of recent whole-genome assemblies. Furthermore, we demonstrate the power of genome-wide approaches and newly developed tools and outline recent cases where genomics have contributed to new ecological and evolutionary knowledge. We explore how the availability of reference assembly enables the efficient application of various statistical tools, and how genomic approaches can provide novel insights into resource polymorphism, host–parasite interactions and to genetic and phenotypic changes associated with climate change and harvesting-induced evolution. In summary, we call for increased integration of genomic tools into ecological research for perch, as well as for other fish species, which is likely to yield novel insights into processes linking the adaptation and plasticity to ecosystem functioning and environmental change. © 2023 The Authors. Ecology of Freshwater Fish published by John Wiley & Sons Ltd.
... Only lymnaeid snails from nine English sites were infected with echinostomatids (Table 1) and their identification was further evaluated using cox1 DNA barcoding and phylogenetic approaches employed by us previously [33,34] (S1 and S2 Tables). Representative samples of each cercarial isolate (a group of identical individuals collected from a single host at one point in time [26]) were examined live with neutral red stain under a stereomicroscope for initial identification using a key to larval digeneans [35] and~20 of each isolate were fixed in 4% formalin for morphological analysis. A pool of~30 cercariae was stored separately in molecular grade ethanol for DNA extraction. ...
... revolutum (s.s.) [14,27]; Ep. recurvatum: [19]), although morphometrics varied between studies (S6 Table). Ep. aconiatum morphology concurred with the key [35], but a detailed description associated with DNA sequences was not located in the published literature. Morphological identification agreed with molecular discrimination. ...
Echinostoma revolutum (sensu stricto) is a widely distributed member of the Echinostomatidae, a cosmopolitan family of digenetic trematodes with complex life cycles involving a wide range of definitive hosts, particularly aquatic birds. Integrative taxonomic studies, notably those utilising nad1 barcoding, have been essential in discrimination of E. revolutum (s.s.) within the 'Echinostoma revolutum' species complex and investigation of its molecular diversity. No studies, however, have focussed on factors affecting population genetic structure and connectivity of E. revolutum (s.s.) in Eurasia. Here, we used morphology combined with nad1 and cox1 barcoding to determine the occurrence of E. revolutum (s.s.) and its lymnaeid hosts in England for the first time, in addition to other echinostomatid species Echinoparyphium aconiatum, Echinoparyphium recurvatum and Hypoderaeum conoideum. Analysis of genetic diversity in E. revolutum (s.s.) populations across Eurasia demonstrated haplotype sharing and gene flow, probably facilitated by migratory bird hosts. Neutrality and mismatch distribution analyses support possible recent demographic expansion of the Asian population of E. revolutum (s.s.) (nad1 sequences from Bangladesh and Thailand) and stability in European (nad1 sequences from this study, Iceland and continental Europe) and Eurasian (combined data sets from Europe and Asia) populations with evidence of sub-population structure and selection processes. This study provides new molecular evidence for a panmictic population of E. revolutum (s.s.) in Eurasia and phylogeographically expands the nad1 database for identification of echinostomatids.
... In the laboratory, each individual of L. stagnalis was placed in a 50 ml glass beaker filled with tap water and exposed to a light source (lamps) for 2 hours to stimulate cercariae shedding. The cercariae of E. aconiatum were recognized based on their morphological features (Cichy and Żbikowska 2016a;Faltýnková et al. 2007). ...
Abstract
The change in the distribution of organisms in freshwater ecosystems due to natural or manmade processes raises the question of the impact of alien species on local communities. Although most studies indicate a negative effect, the positive one is more difficult to discern, especially in multispecies systems, including hosts and parasites. The purpose of the study was to check whether the presence of an alien host, Potamopyrgus antipodarum, reduces the intensity of Echinoparyphium aconiatum metacercariae in a native host, Radix spp. We additionally tested the impact of water temperature and the biomass of the alien host on the dilution effect. We experimentally studied (1) the lifespan of echinostome cercariae in different temperatures, (2) the infectivity of cercariae toward the alien host and native host, and (3) the impact of different biomass of the alien host on the intensity of metacercariae in the native host. We found that cercarial survival and infectivity were temperature dependent. However, cercarial survival decreased with increasing temperature, contrary to cercarial infectivity. Echinostome cercariae entered the renal cavity of both the native host and alien host, and successfully transformed into metacercariae. The number of metacercariae in the native host decreased with the increasing biomass of the alien host. Our results indicate that lymnaeids may benefit from the co-occurrence with P. antipodarum, as the presence of additional hosts of different origins may reduce the prevalence of parasites in native communities. However, the scale of the dilution effect depends not only on the increased spectrum of susceptible hosts but also on the other variables of the environment, including water temperature and host density.
... Snails were transferred into small glass containers with a volume of 50 ml. The emergence of cercariae was stimulated by heating the containers with a lamp for 1-2 h (Faltýnková et al. 2007). The 0.05% neutral red stain was used for their vital staining (5-10 min). ...
... The final species identification of cercariae was performed after studying stained preparations using a stereodissecting microscope Zeiss Discovery V.8 (Carl Zeiss AG, Oberkochen, Germany) and microscope Axio Imager.A2 (Carl Zeiss AG, Oberkochen, Germany). The species identification of trematode cercariae was performed using keys provided by Combes (1980) and Faltýnková et al. (2007). Identification of S. robusta cercariae (hosts are mollusks Planorbis planorbis from Medvedevo) was carried out using molecular analysis in our previous laboratory experiments (Svinin et al. 2022). ...
The anomaly P is a widespread morphological anomaly, which occurs in some groups of amphibians, caused by the trematode parasite Strigea robusta (Digenea: Strigeidae). This anomaly has been previously recorded in water frogs of the genus Pelophylax and toads of the genera Bufo and Bufotes. The anomaly P includes symmetrical polydactyly cases as a mild attenuated form of the complex syndrome, which in severe cases includes strong deformations of hindlimbs and forelimbs. Strigea robusta has a complex 3-host life cycle using planorbid mollusks as the first intermediate hosts, amphibian larvae as the second intermediate hosts, and anatid birds as the definitive hosts. Herein, we described new records of the anomaly P syndrome in water frogs of the genus Pelophylax from the northeastern parts of their ranges. Symmetrical polydactyly (as a mild form of the anomaly P syndrome) was found in 30 individuals of three species of water frogs from seven localities: in 25 individuals of P. lessonae from four waterbodies, in four individuals of P. ridibundus from three waterbodies, and one individual of P. esculentus. In Gusevo pond, three individuals of P. lessonae with severe cases of the syndrome were found. This is the first record of the anomaly P in reliably identified hybridogenetic edible frogs (P. esculentus) that have been identified in nature. Additionally, we provided new data about the occurrence of the anomaly P and the prevalence of the trematode S. robusta in mollusks taken from two water bodies where anomalous water frogs were found.
