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Parasitology Research Oct 2021Trematode larvae (metacercariae) causing black spot disease occur frequently in gills, fins, skin and the superficial muscle layers of marine fish. Species within the...
Morphological and molecular identification of Cryptocotyle lingua metacercariae isolated from Atlantic cod (Gadus morhua) from Danish seas and whiting (Merlangius merlangus) from the English Channel.
Trematode larvae (metacercariae) causing black spot disease occur frequently in gills, fins, skin and the superficial muscle layers of marine fish. Species within the genus Cryptocotyle Lühe, 1899 are frequently associated with this disease. Descriptions of the metacercarial stage are relatively limited and none has hitherto been reported from fish from the English Channel. The present study reports the morphological and molecular identifications of encysted black spot-inducing parasites from whiting (Merlangius merlangus) and Atlantic cod (Gadus morhua) caught respectively from the north coast of France (English Channel) and from Danish sea waters. Metacercariae were characterised morphologically based on microscopic observations and molecularly using Sanger sequencing of fragments of the mitochondrial cox1 gene and rDNA ITS region. Morphological data were compared with available data in the literature. Phylogenetic trees including reference sequences were built to confirm morphological and molecular identifications. This survey constitutes the first description of C. lingua metacercariae in the English Channel ecosystems.
Topics: Animals; Denmark; Ecosystem; Gadus morhua; Metacercariae; Phylogeny
PubMed: 34448921
DOI: 10.1007/s00436-021-07278-6 -
The Journal of Parasitology Apr 2020Adults of a species of Cryptocotyle were found infecting the intestine of the kelp gull, Larus dominicanus Lichtenstein, 1823, and metacercariae were found in the fins...
A New Species of Cryptocotyle (Digenea: Heterophyidae) Infecting Kelp Gull and a Galaxiid Fish in Patagonian Freshwater Environments: Morphological and Molecular Analyses.
Adults of a species of Cryptocotyle were found infecting the intestine of the kelp gull, Larus dominicanus Lichtenstein, 1823, and metacercariae were found in the fins and muscle of the galaxiid fish, Galaxias platei Steindachner, 1898 (local name "puyen grande"), in Nahuel Huapi National Park (Patagonia). Morphometrics and genetic markers of mitochondrial cytochrome oxidase (COI) and ribosomal internal transcribed spacer 1 (ITS1) confirmed that adults and metacercariae were conspecific and represent a new species, Cryptocotyle dominicana n. sp. The only congener known from South America (Cryptocotyle thapari McIntosh, 1953) matures in river otters (Lutra spp. and Pteronura spp.) in Brazil and Bolivia and differs from the new species in the arrangement of the testes, which are located in tandem in the species from otters. Adults of the new species resemble Cryptocotyle lingua (Creplin, 1825) Fischoeder, 1903 from marine environments of the Northern Hemisphere, both species being characterized by having a linguiform body, oblique testes, and vitelline follicles that extend posteriorly to the level of the ventral sucker. Considering the morphological findings that differentiate the new species from other Cryptocotyle, as well as the molecular analysis that shows significant differences from C. lingua, we conclude that these specimens represent a new species, the first of the genus Cryptocotyle to be described from birds in South America.
Topics: Animals; Argentina; Bayes Theorem; Bird Diseases; Charadriiformes; Fish Diseases; Fresh Water; Heterophyidae; Likelihood Functions; Osmeriformes; Trematode Infections
PubMed: 32164027
DOI: 10.1645/18-44 -
Zebrafish Dec 2019This study reports the presence of cartilaginous cysts in zebrafish gills, purchased at the end of 2012 before the application of the Italian Legislative Decree 26/2014...
This study reports the presence of cartilaginous cysts in zebrafish gills, purchased at the end of 2012 before the application of the Italian Legislative Decree 26/2014 and used for experimental research. It highlights the importance of using specific pathogen-free organisms from reliable production establishments to avoid obtaining false results in experiments. Of 20 samples analyzed, 4 showed cysts in gills, with abnormal tissue modification and cartilaginous metaplasia induced by prolonged parasitic insult. The results obtained from the periodic health monitoring program showed the presence of metacercariae of digenean trematodes, specifically identified as .
Topics: Animals; Female; Fish Diseases; Gills; Heterophyidae; Italy; Male; Prevalence; Trematode Infections; Zebrafish
PubMed: 31237524
DOI: 10.1089/zeb.2019.1744 -
The Journal of Parasitology Oct 2020Here we describe a new heterophyid species, Heterophyes yacyretana n. sp., and resolve its life cycle experimentally. We found the prosobranch snail Aylacostoma...
The Life Cycle of Heterophyes yacyretana n. sp. (Digenea, Heterophyidae), Parasitic in the Endemic Snail Aylacostoma chloroticum (Caenogastropoda, Thiaridae) in Argentina.
Here we describe a new heterophyid species, Heterophyes yacyretana n. sp., and resolve its life cycle experimentally. We found the prosobranch snail Aylacostoma chloroticum in Candelaria, Province of Misiones, Argentina (a sector of the High Paraná River affected by the Yacyretá Dam), naturally infected with opisthorchioid cercariae. These cercariae lacked pigmented eyespots as well as body pigment and possessed 7 pairs of penetration glands arranged in 2 lateral bands, together with 18 pairs of flame cells and a V-shaped excretory vesicle. We exposed specimens of 21 fish species to emerging cercariae and obtained metacercariae from the muscles of the caudal peduncle of 3 species of siluriform fish, and adults from chicks infected with experimentally obtained metacercariae from the albino variety of the bronce corydoras, Corydoras aeneus. The new species differs from other species in the genus by the number of sclerites on the genital sac, the distribution of the vitelline follicles, and the combination of the size relationship of the suckers and the genital sac with respect to the posterior extent of intestinal ceca. Heterophyes yacyretana is the first species of the genus reported from the Americas.
Topics: Animals; Argentina; Cercaria; Chickens; Fish Diseases; Fishes; Gastropoda; Heterophyidae; Life Cycle Stages; Metacercariae; Rivers
PubMed: 33027811
DOI: 10.1645/19-168 -
Journal of Fish Diseases Nov 2021Some trematode metacercariae, including marine digeneans belonging to the genus Cryptocotyle, induce black spots in target tissues due to the attraction of fish host...
Some trematode metacercariae, including marine digeneans belonging to the genus Cryptocotyle, induce black spots in target tissues due to the attraction of fish host melanophores. To promote precise quantification of infection, the counting of black spots has to be confirmed by reliable quantification of metacercariae after tissue digestion. This process ensures the isolation of undamaged parasites for morphological and molecular identification. The aim of this work was to optimize the pepsin digestion protocol and to assess the duration of viability of Cryptocotyle metacercariae in fish post-mortem (pm). Four digestion protocols were compared by measuring the viability rate of metacercariae. The present study shows that the orbital digestion method was the least destructive for metacercariae and allowed better quantification of Cryptocotyle infection. Moreover, morphological identification seemed reliable up to 8 days pm for Cryptocotyle infection.
Topics: Animals; Fish Diseases; Gadiformes; Heterophyidae; Metacercariae; Trematode Infections
PubMed: 34289140
DOI: 10.1111/jfd.13495 -
Diseases of Aquatic Organisms Nov 2019Acanthurus spp. of St. Kitts and other Caribbean islands, including ocean surgeonfish A. bahianus, doctorfish A. chirurgus, and blue tang A. coeruleus, frequently show...
Acanthurus spp. of St. Kitts and other Caribbean islands, including ocean surgeonfish A. bahianus, doctorfish A. chirurgus, and blue tang A. coeruleus, frequently show multifocal cutaneous pigmentation. Initial reports from the Leeward Antilles raised suspicion of a parasitic etiology. The aim of this study was to quantify the prevalence of the disease in St. Kitts' Acanthuridae and describe its pathology and etiology. Visual surveys demonstrated consistently high adjusted mean prevalence at 3 shallow reefs in St. Kitts in 2017 (38.9%, 95% CI: 33.8-43.9) and 2018 (51.5%; 95% CI: 46.2-56.9). There were no differences in prevalence across species or reefs, but juvenile fish were less commonly affected than adults. A total of 29 dermatopathy-affected acanthurids were sampled by spearfishing for comprehensive postmortem examination. Digenean metacercariae were dissected from <1 mm cysts within pigmented lesions. Using partial 28S rDNA sequence data they were classified as Family Heterophyidae, members of which are commonly implicated in black spot disease of other fishes. Morphological features of the parasite were most typical of Scaphanocephalus spp. (Creplin, 1842), and 2 genetic profiles were obtained suggesting more than 1 digenean species. Histologically, pigmented lesions had mild chronic perivascular dermatitis and increased melanophores and melanin density, often centered on encysted digenean metacercariae. In 1 affected A. chirurgus, similar metacercariae were histologically identified in skeletal and cardiac muscle. Further research is needed to clarify impact on host fitness, establish the number of heterophyid digenean species that cause black spots on Caribbean fishes and to determine the intermediate and definitive host species.
Topics: Animals; Caribbean Region; Dermatitis; Metacercariae; Perciformes; West Indies
PubMed: 31777400
DOI: 10.3354/dao03419 -
Journal of Helminthology Dec 2023is a small trematode genus belonging to the family Opistorchiidae. The genus currently contains only three species associated with marine fish as intermediate hosts and...
is a small trematode genus belonging to the family Opistorchiidae. The genus currently contains only three species associated with marine fish as intermediate hosts and fish-eating birds as definitive hosts. Here, specimens of were collected from the Osprey, , and the White mullet, in the Yucatán Peninsula, Mexico. We report for the first-time DNA sequences of adult specimens of , particularly , as well as a sequence of a different species sampled as metacercaria. Morphological comparisons of confirmed the identity of the adult specimens, with minor morphological variations; Scanning electron photomicrographs were included, and the species was re-described. Phylogenetic analysis based on 28S rDNA sequences showed that is monophyletic within Opisthorchiidae and consists of three independent lineages. Sequences of adults are identical to those of Instead, the sequence of the metacercaria sampled from the mesentery of nested with specimens reported as sp. from a labrid fish in the Mediterranean Sea, herein named it as sp. 2.
Topics: Animals; Mexico; Phylogeny; DNA, Helminth; Trematoda; Heterophyidae; Fishes; Smegmamorpha; Falconiformes; Metacercariae; Fish Diseases; Trematode Infections
PubMed: 38095098
DOI: 10.1017/S0022149X23000834 -
The Journal of Infectious Diseases Jan 2023We document that 3 human-infectious trematodes and their introduced first intermediate host snail (Melanoides tuberculata) are widespread throughout southern California....
We document that 3 human-infectious trematodes and their introduced first intermediate host snail (Melanoides tuberculata) are widespread throughout southern California. We surveyed 41 fishing localities, 19 of which harbored snails infected with zoonotic trematodes. Two of the parasites, Haplorchis pumilio and Centrocestus formosanus, are fishborne intestinal trematodes recognized as being important human pathogens in other areas of the world; the third, Philophthalmus gralli, can infect the human eye. An additional 5 species detected infecting M. tuberculata are likely of little direct threat to people; however, they may be recently introduced to the Americas, highlighting the risk that additional pathogenic trematodes transmitted by the snail in its native range could be introduced to the United States. The current, possible human-infection risk in California clarifies the need to consider the introduced snail and its parasites from a public health perspective anywhere in the United States the snail has been introduced.
Topics: Animals; Humans; Trematode Infections; Snails; Trematoda; Parasites; California
PubMed: 36214840
DOI: 10.1093/infdis/jiac413 -
Diseases of Aquatic Organisms May 2021In this study, Scaphanocephalus parasite (Platyhelminthes: Heterophyidae) metacercariae were found in Siganus argenteus (forktail rabbitfish or streamlined spinefoot) in...
In this study, Scaphanocephalus parasite (Platyhelminthes: Heterophyidae) metacercariae were found in Siganus argenteus (forktail rabbitfish or streamlined spinefoot) in the Arabian Gulf of Jubail province, Saudi Arabia. The findings may constitute new host and locality records for this parasite. Based on the number of black spots containing parasite cysts per fish, our study indicated that Siganus argenteus had high infection intensities of encysted metacercariae belonging to the genus Scaphanocephalus. Of the 3500 S. argenteus specimens examined, 800 (22.9%) showed multiple black cysts over the entire body surface, including the membranous parts of fins, while none were seen on the internal organs. The prevalence of infection was highest in summer (June-August) (8.8%). The excysted metacercariae differed morphologically from previously identified Scaphanocephalus spp. Molecular analysis of rDNA showed 100% identity with an unnamed Scaphanocephalus sp. reported in Caribbean fish. Therefore, our findings may indicate a new species of this previously rarely recorded fish parasite. The histopathological examination revealed that the encysted parasites were restricted to the dermal layer of the skin and surrounded by melanophores and a fibrous connective tissue capsule, with focal myositis and Zenker's necrosis in the underlying muscle tissue. The characteristically 'winged' parasite was clearly observed within the cysts. The high prevalence of Scaphanocephalus infection in siganid fish we detected requires further epidemiological study.
Topics: Animals; Caribbean Region; Fish Diseases; Heterophyidae; Metacercariae; West Indies
PubMed: 34042069
DOI: 10.3354/dao03586 -
Parasitology International Aug 2021The cryptic diversity of trematodes was evaluated in the Nagayama-Shinkawa River, an artificial canal of the Ishikari River System of Hokkaido, Japan. Numerous migratory...
Trematode diversity in freshwater snails from a stopover point for migratory waterfowls in Hokkaido, Japan: An assessment by molecular phylogenetic and population genetic analyses.
The cryptic diversity of trematodes was evaluated in the Nagayama-Shinkawa River, an artificial canal of the Ishikari River System of Hokkaido, Japan. Numerous migratory waterfowls use the canal as a stopover point in every spring season. The lymnaeid snail, Radix auricularia, and the semisulcospirid snail, Semisulcospira libertina, colonize the static and flowing water areas, respectively. The trematode fauna of the two snails was assessed by molecular phylogenetic and population genetic analyses. Each of distinctive clades in mitochondrial DNA trees was arbitrarily set as a species. In total, 14 species of the families Diplostomidae, Echinostomatidae, Notocotylidae, Plagiorchiidae, and Strigeidae occurred in R. auricularia, wherease S. libertina harbored 10 species of the families Echinochasmidae, Heterophyidae, Notocotylidae, and Lecithodendridae and Cercaria creta, an unclassified species whose adult stage is still unknown. The species diversity of the larval trematodes could be recognized as a "hot spot", suggesting that the seasonal visit of waterfowls is very important to spread trematodes and to keep their diversity. A high intraspecific genetic diversity was observed in the echinostomatid, notocotylid, echinochasmid, and heterophyid species, whose definitive hosts include birds. It seems likely that each of the parasite populations is always disturbed by repeated visits of waterfowls.
Topics: Animal Migration; Animals; Anseriformes; Host-Parasite Interactions; Japan; Phylogeny; RNA, Helminth; RNA, Ribosomal, 28S; Rivers; Seasons; Snails; Trematoda
PubMed: 33753234
DOI: 10.1016/j.parint.2021.102329