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Parasitology Research Oct 2023Trematodes of the genus Metagonimus Katsurada, 1912 (Digenea: Heterophyidae) are zoonotic parasites that cause infections in humans, with most cases reported in...
Trematodes of the genus Metagonimus Katsurada, 1912 (Digenea: Heterophyidae) are zoonotic parasites that cause infections in humans, with most cases reported in Southeast Asia. Larvae from the second intermediate host, called metacercariae, of one of human-infecting species, M. yokogawai (Katsurada, 1912), have been reported from cyprinoid fish in Europe. In the present study, we provided DNA-based evidence that metacercariae of Metagonimus, which are commonly found in the scales of various cyprinoids in Central Europe (Danube River in Hungary) do not belong to M. yokogawai. Sequence analysis of the ITS region, 28S rDNA, and cox1 genes showed that this species is clearly distinct from all Asian species, including M. yokogawai, which probably does not occur in Europe. Metacercariae from cyprinoids might belong to Metagonimus romanicus (Ciurea, 1915), an insufficiently known species described from Romania.
Topics: Heterophyidae; Animals; Rivers; Hungary; Cypriniformes; Phylogeny; RNA, Ribosomal, 28S; Electron Transport Complex IV
PubMed: 37572128
DOI: 10.1007/s00436-023-07932-1 -
Parasites, Hosts and Diseases May 2023The present study aimed to determine the infection status of trematode metacercariae and adults in cyprinoid fish from the Khun Thale Swamp in Surat Thani, Southern...
The present study aimed to determine the infection status of trematode metacercariae and adults in cyprinoid fish from the Khun Thale Swamp in Surat Thani, Southern Thailand, with epidemiologic and faunistic viewpoints. In 2020, 577 fish in 15 species were collected in the summer (February-April) and rainy (September-November) seasons. Fish were individually examined for trematode metacercariae in the whole body and adults in the gastrointestinal tract using a stereomicroscope. Three species of digenetic trematode metacercariae, i.e., Haplorchis taichui, Haplorchoides mehrai, and Centrocestus formosanus, were detected in the muscle, fin, and/or scale of fish. Two species of adult flukes, including Rohdella siamensis and Helostomatis cyprinorum, were collected in the intestines. The prevalence of overall trematode infections was 32.4% (187/577 fish), which was higher in the rainy season (41.4%; 118/285) than in the summer season (23.6%; 69/292). The metacercariae of H. taichui and H. mehrai were detected in 7 fish species each, and those of C. formosanus were found only in Rasbora toneri. The aspidogastrean trematode R. siamensis (adult) was detected in Babonymus gonionotus. A digenean species, H. cyprinorum (adult), was found in Labiobarbus siamensis and Osteochilus vittatus. The present study has first confirmed that the metacercariae of heterophyid flukes, including H. taichui, H. mehrai, and C. formosanus, and adults of R. siamensis (Aspidogastrea) and H. cyprinorum (Digenea) are infected in some species of the cyprinoid fish from the Khun Thale Swamp in Surat Thani, Thailand.
Topics: Animals; Metacercariae; Thailand; Wetlands; Fish Diseases; Trematoda; Heterophyidae; Cypriniformes
PubMed: 37258263
DOI: 10.3347/PHD.23030 -
Emerging Infectious Diseases Nov 2022A survey of intestinal helminths targeting 1,440 schoolchildren in 12 primary schools on Kome Island (Lake Victoria), Tanzania, revealed small trematode eggs in 19...
A survey of intestinal helminths targeting 1,440 schoolchildren in 12 primary schools on Kome Island (Lake Victoria), Tanzania, revealed small trematode eggs in 19 children (1.3%), seemingly of a species of Haplorchis or Heterophyes. The eggs were molecularly confirmed to be Haplorchis pumilio on the basis of 18S and 28S rDNA sequences.
Topics: Child; Animals; Humans; Heterophyidae; Lakes; Tanzania; Trematode Infections; DNA, Ribosomal
PubMed: 36286076
DOI: 10.3201/eid2811.220653 -
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 -
International Journal For Parasitology.... Apr 2022() n. sp. is described based on adults from experimentally infected ducklings () fed with metacercariae from the visceral serosa of the Mediterranean banded killifish,...
() n. sp. is described based on adults from experimentally infected ducklings () fed with metacercariae from the visceral serosa of the Mediterranean banded killifish, (Cyprinodontiformes: Aphaniidae), from coastal lagoons in northeastern Italy (Emilia-Romagna Region). The new species is placed into the subgenus because of the presence of a single row of circumoral spines, vitelline follicles being confined between the ventral sucker and testes, and uterine loops not reaching anterior to the ventral sucker. () n. sp. differs from other members of the subgenus , as well as other species of , by the number (27-33) of circumoral spines which are 13.5-17 μm long and 3.5-5 μm wide, and by the morphology of a gonotyl which is composed of about 8 large refractile pockets. The occurrence of metacercariae in indicates that the life cycle of the new species is completed in brackish water lagoons. It is the fourth species of described in Europe and may be endemic to the Mediterranean region because its second (fish) intermediate host is endemic to this region.
PubMed: 36117855
DOI: 10.1016/j.ijppaw.2021.10.003 -
Journal of Helminthology Jul 2022The assassin snail genus is widespread in Southeast Asia, and is distributed all over the world via the aquarium trade. One species of genus , , is known to act as...
The assassin snail genus is widespread in Southeast Asia, and is distributed all over the world via the aquarium trade. One species of genus , , is known to act as intermediate host of parasitic trematodes. This study investigates the taxonomic diversity of larval trematodes infecting . and in Thailand. Larval trematodes were identified by combining morphological and DNA sequence data (cytochrome oxidase I and internal transcribed spacer 2). Species delimitation methods were used to explore larval trematode species boundaries. A total of 1107 specimens of sp. were collected from 25 localities in Thailand. Sixty-two specimens of . ( = 33) and . ( = 29) were infected by zoogonid cercariae, heterophyid metacercariae and echinostome metacercariae, with an overall prevalence of 5.6% (62/1107) and population-level prevalences in the range of 0.0-22.3%. DNA sequence data confirmed that the larval trematodes belong to the families Echinostomatidae, Heterophyidae and Zoogonidae. As such, this is the first report of zoogonid cercariae and heterophyid metacercariae in . , and echinostome metacercariae in . . Moreover, this study provides evidence of tentative species-level differentiation between Thai sp. and Cambodian , as well as within , and .
Topics: Animals; Cercaria; Echinostoma; Humans; Larva; Metacercariae; Snails; Thailand; Trematoda
PubMed: 35894430
DOI: 10.1017/S0022149X22000463 -
Parasitology International Oct 2022A nationwide fish survey was conducted in Japan to detect metacercariae of the genus Metagonimus (Trematoda: Heterophyidae). The metacercariae were subjected to DNA...
A nationwide fish survey was conducted in Japan to detect metacercariae of the genus Metagonimus (Trematoda: Heterophyidae). The metacercariae were subjected to DNA barcoding for molecular species identification. A phylogeny inferred from the sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) prompted us to recognize three cryptic species complexes (i.e., the M. miyatai complex, the M. takahashii complex, and the M. katsuradai complex). Each complex included one or two undescribed species. For morphological description, adult flukes of each species were raised through the experimental infections of immunosuppressed mice. We propose M. saitoi n. sp., M. kogai n. sp., M. shimazui n. sp., and M. kinoi n. sp., based on their phylogeny, morphology, biogeography, and ecology (host-parasite relationships). The originally described species, M. miyatai, was split into M. miyatai sensu stricto and M. saitoi n. sp. The former is distributed mainly in eastern Japan and uses the sweetfish (Plecoglossus altivelis) and daces (Pseudaspius hakonensis and Ps. sachalinensis) as principal second intermediate hosts, while the latter is in western Japan and its principal fish hosts are the dark chub (Nipponocypris temminckii) and the pale chub (Opsariichthys platypus). The present survey resolves a long-standing controversy on the microtaxonomy of Metagonimus in Japan since the first discovery of Metagonimus yokogawai in 1912, and shows that 10 species of Metagonimus are still distributed in Japan, although human metagonimiasis is almost eradicated.
Topics: Animals; Fishes; Heterophyidae; Japan; Metacercariae; Mice; Trematoda; Trematode Infections
PubMed: 35643322
DOI: 10.1016/j.parint.2022.102605 -
Parasitology Sep 2022Foodborne trematodes (FBT) of public health significance include liver flukes ( and ), lung flukes ( and several other spp.) and intestinal flukes, which include... (Review)
Review
Foodborne trematodes (FBT) of public health significance include liver flukes ( and ), lung flukes ( and several other spp.) and intestinal flukes, which include heterophyids ( and ), echinostomes ( and ) and miscellaneous species, including and . These trematode infections are distributed worldwide but occur most commonly in Asia. The global burden of FBT diseases has been estimated at about 80 million, however, this seems to be a considerable underestimate. Their life cycle involves a molluscan first intermediate host, and a second intermediate host, including freshwater fish, crustaceans, aquatic vegetables and freshwater or brackish water gastropods and bivalves. The mode of human infection is the consumption of the second intermediate host under raw or improperly cooked conditions. The major pathogenesis of and spp. infection includes inflammation of the bile duct which leads to cholangitis and cholecystitis, and in a substantial number of patients, serious complications, such as liver cirrhosis and cholangiocarcinoma, may develop. In lung fluke infections, cough, bloody sputum and bronchiectasis are the most common clinical manifestations. However, lung flukes often migrate to extrapulmonary sites, including the brain, spinal cord, skin, subcutaneous tissues and abdominal organs. Intestinal flukes can induce inflammation in the intestinal mucosa, and they may at times undergo extraintestinal migration, in particular, in immunocompromised patients. In order to control FBT infections, eating foods after proper cooking is strongly recommended.
Topics: Animals; Echinostoma; Fascioliasis; Heterophyidae; Humans; Inflammation; Trematoda; Trematode Infections
PubMed: 35591777
DOI: 10.1017/S0031182022000725 -
Parasitology Research Mar 2022In this work, for the first time, the genetic variability of the Metagonimus suifunensis population in the Russian southern Far East was estimated based on the...
In this work, for the first time, the genetic variability of the Metagonimus suifunensis population in the Russian southern Far East was estimated based on the full-length sequences of the nad1 gene of mitochondrial DNA. In addition, for a sample of the same size, the sequences of cox1 and cytb genes, previously used for population studies for M. suifunensis, were reanalysed. Three markers were combined to a common sequence, and the obtained data were studied. Despite the higher level of variability, nad1 and cox1 mtDNA genes did not reveal subdivisions within the population. The combined dataset made it possible to determine that the sample from the Odyr River was the centre of the species' range formation and clarified the continental migration route of the parasite from south to north. According to the data obtained, it was presumed that piscivorous birds participate in the life cycle of the parasite. The subdivision within population revealed that using all three mitochondrial markers is consistent with the features of differentiation within populations of related species, but the reasons for its formation remain unclear due to the insufficient amount of data and the use of different markers in studies of different species.
Topics: Animals; DNA, Mitochondrial; Asia, Eastern; Genetic Variation; Heterophyidae; Mitochondria; Phylogeny; Russia
PubMed: 35133488
DOI: 10.1007/s00436-022-07456-0 -
Parasitology Research Feb 2022Freshwater snails play an essential role in the transmission of trematode parasitic flatworms that can infect wild and domestic animals, as well as humans. This study...
Freshwater snails play an essential role in the transmission of trematode parasitic flatworms that can infect wild and domestic animals, as well as humans. This study aimed to investigate the rate of cercarial infections in freshwater snails collected from two study areas, Inlay Lake and Yezin Dam, in Myanmar. A total of 4,740 snail samples were collected from Inlay Lake (n = 3,837) and Yezin Dam (n = 903), and infection rate by cercarial emergence was examined. Cercarial DNA samples were analysed by PCR. Based on morphological characteristics, eleven snail species and eight cercarial types were identified. Snails of Melanoides tuberculata in the family Thiaridae were found as the most abundant, followed by Indoplanorbis exustus of the family Planorbidae, in both study areas. The infection rate by cercarial emergence in snails in Inlay Lake and Yezin Dam was 5.8% (224/3,837) and 48.6% (439/903), respectively. Echinostome cercariae showed the highest infection rate in both study areas. Phylogenetic analysis of cercarial internal transcribed spacer 2 (ITS2) sequences revealed that at least seven cercaria types belonged to five digenean trematode families, two of which were zoonotic trematodes in the families of Opisthorchiidae/Heterophyidae and Schistosomatidae. Furthermore, cercarial 28S ribosomal RNA gene analysis showed that the furcocercous cercariae in Yezin Dam were identified as Schistosoma spindale, a causative agent of ruminant schistosomiasis. This is the first report on zoonotic trematode cercariae in snails in Myanmar. The findings indicate that various snail species act as intermediate host for trematode species that infect aquatic animals, mammals and humans in the country.
Topics: Animals; Cercaria; Humans; Lakes; Myanmar; Phylogeny; Schistosomatidae; Snails; Trematoda; Trematode Infections
PubMed: 35032219
DOI: 10.1007/s00436-022-07428-4