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Food and Waterborne Parasitology 2017Fishborne heterophyid trematodes infecting humans are at least 29 species worldwide and belong to 13 genera. Its global burden is much more than 7 million infected... (Review)
Review
Fishborne heterophyid trematodes infecting humans are at least 29 species worldwide and belong to 13 genera. Its global burden is much more than 7 million infected people. They include (. , . , . , . , and . ), (. , . , . , and . ), (. , . , . , and . ), (. and . ), (. ), (. ), (. , . , . , and . ), (. and . ), (. and . ), (. ), (. ), (. ), and (. ). Human infections are scattered around the world but the major endemic areas are located in Southeast Asia. The source of human infection is ingestion of raw or improperly cooked fish. The pathogenicity, host-parasite relationships, and clinical manifestations in each species infection are poorly understood; these should be elucidated particularly in immunocompromised hosts. Problems exist in the differential diagnosis of these parasitic infections because of close morphological similarity of eggs in feces and unavailability of alternative methods such as serology. Molecular diagnostic techniques are promising but they are still at an infant stage. Praziquantel has been proved to be highly effective against most of the patients infected with heterophyid flukes. Epidemiological surveys and detection of human infections are required for better understanding of the geographical distribution and global burden of each heterophyid species. In this review, the most updated knowledge on the morphology, biology, epidemiology, pathogenesis and pathology, immunology, clinical manifestations, diagnosis and treatment, and prevention and control of fishborne zoonotic heterophyid infections is provided.
PubMed: 32095640
DOI: 10.1016/j.fawpar.2017.09.001 -
The Korean Journal of Parasitology Aug 2017The prevalence of Centrocestus formosanus metacercariae was investigated in ornamental fish purchased from a pet shop in Chiang Mai, Thailand, including Carassius...
The prevalence of Centrocestus formosanus metacercariae was investigated in ornamental fish purchased from a pet shop in Chiang Mai, Thailand, including Carassius auratus (goldfish), Cyprinus carpio (Koi), Poecilia latipinna (Sailfin Molly), Danio rerio (Zebrafish), and Puntigrus tetrazona (Tiger barb). The parasite species was identified by the morphology of worms as well as by a molecular approach using ITS2. The results showed that 50 (33.3%) of 150 fish examined were infected with the metacercariae. The highest prevalence was found in C. auratus (83.3%), and the highest intensity was noted in C. carpio (70.8 metacercariae/fish). The most important morphological character was the presence of 32-34 circumoral spines on the oral sucker. The phylogenetic studies using the rRNA ITS2 region revealed that all the specimens of C. formosanus in this study were grouped together with C. formosanus in GenBank database. This is the first report on ornamental fish, C. carpio, P. latipinna, D. rerio, and P. tetrazona, taking the role of second intermediate hosts of C. formosanus in Thailand. Prevention and control of metacercarial infection in ornamental fish is urgently needed.
Topics: Animals; Databases, Genetic; Fish Diseases; Genes, Helminth; Heterophyidae; Host-Parasite Interactions; Metacercariae; Phylogeny; Prevalence; Thailand; Trematode Infections
PubMed: 28877579
DOI: 10.3347/kjp.2017.55.4.445 -
The Korean Journal of Parasitology Jun 2017During civil engineering construction near Sejong-ro, Jongro-ku, Seoul, cultural sites were found that are thought to have been built in the 15th century. This area was...
During civil engineering construction near Sejong-ro, Jongro-ku, Seoul, cultural sites were found that are thought to have been built in the 15th century. This area was home to many different people as well as the leaders of the Yi dynasty. To gain further insight into the life styles of the inhabitants of the old capital, soil samples were collected from various areas such as toilets, water foundations, and drainage ways. Parasite eggs were examined by microscopy after 5 g soil samples were rehydrated in 0.5% trisodium phosphate solution. A total of 662 parasite eggs from 7 species were found. Species with the highest number of eggs found were (n=483), followed by (138), (21), (8), (6), (4), and (2). These findings indirectly indicate the food habits of the people in Yi dynasty.
Topics: Animals; Archaeology; Ascaris lumbricoides; Clonorchis sinensis; Fasciola hepatica; Feeding Behavior; Heterophyidae; History, 15th Century; Humans; Life Style; Paragonimus westermani; Parasite Egg Count; Parasitology; Republic of Korea; Soil; Trichuris
PubMed: 28719964
DOI: 10.3347/kjp.2017.55.3.357 -
The Korean Journal of Parasitology Feb 2017The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual...
The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.
Topics: Animals; Cluster Analysis; DNA, Helminth; DNA, Ribosomal Spacer; Fresh Water; Microscopy; Phylogeny; Prevalence; Sequence Analysis, DNA; Snails; Thailand; Trematoda
PubMed: 28285506
DOI: 10.3347/kjp.2017.55.1.47 -
The Korean Journal of Parasitology Feb 2017This study aimed to investigate the morphology and reconstruct the phylogenetic relationships of originating from 5 species of freshwater fish, i.e., , and , in Chiang...
This study aimed to investigate the morphology and reconstruct the phylogenetic relationships of originating from 5 species of freshwater fish, i.e., , and , in Chiang Mai province, Thailand. Sequence-related amplified polymorphism (SRAP) and phylogeny based on internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (CO1) were performed. The results showed similar morphologies of adult from day 5 after infection in chicks. originated from 4 species of freshwater fish had the same number of circumoral spines on the oral sucker, except for those from which revealed 34 circumoral spines. The phylogenetic tree obtained from SRAP profile and the combination of ITS2 and CO1 sequence showed similar results that were correlated with the number of circumoral spines in adult worms. Genetic variability of also occurred in different species of freshwater fish hosts. However, more details of adult worm morphologies and more sensitive genetic markers are needed to confirm the species validity of with 34 circumoral spines originating from in the future.
Topics: Animals; Cluster Analysis; DNA, Helminth; DNA, Ribosomal Spacer; Electron Transport Complex IV; Fish Diseases; Fishes; Fresh Water; Heterophyidae; Microscopy; Phylogeny; Sequence Analysis, DNA; Thailand; Trematode Infections
PubMed: 28285504
DOI: 10.3347/kjp.2017.55.1.31 -
Nutricion Hospitalaria Feb 2017To investigate the species of zoonotic trematodes and the endemic infection status in the domestic animals in Huainan areas, north Anhui province of China, we intent to...
BACKGROUND
To investigate the species of zoonotic trematodes and the endemic infection status in the domestic animals in Huainan areas, north Anhui province of China, we intent to provide evidences for prevention of the parasitic zoonoses.
METHODS
The livestock and poultry (definitive hosts) were purchased from the farmers living in the water areas, including South Luohe, Yaohe, Jiaogang and Gaotang Lakes, and dissected the viscera of these collected hosts to obtain the parasitic samples. Then the specimens were microscopically identified, with reference to the descriptions in previous literatures for counting the zoonotic species found in these areas.
RESULTS
A total of 41 species were detected in the domestic samples, in which 23 were zoonotic trematodes, and 18 were internal trematodes of animals. Of the 41 species, 38 were novel records in Huainan areas, and 12 were newly detected in Anhui province, including Metorchis anatinus, Echinostoma hortense, E. cinetorchis, E. angustitestis, E. lindoensis, E. nordiana, E. ilocanum, Metagonimus yokogawai, Prosthogonimus gracilis, P. skrjabini, P. anatinusand Trichobilharzia sp. which generally occurred in definitive hosts of chicken, ducks, geese, dogs, cattle, buffaloes, sheep, goats and pigs, respectively.
CONCLUSION
A large quantity of livestock and poultry are fed by the local farmers living along the river banks in Huainan area, suggesting that the population in that area are at higher risks of natural focus of zoonotic infections, since these animals are favorable definitive hosts to the zoonotic trematodes.
Topics: Animals; Animals, Domestic; China; Host-Parasite Interactions; Humans; Livestock; Trematoda; Zoonoses
PubMed: 28244789
DOI: 10.20960/nh.994 -
Asian Pacific Journal of Tropical... Feb 2017To examine the taxonomic boundaries in the Stellantchasmus populations in different hosts and reveal the cryptic speciation of the Stellantchasmus in Thailand based on...
OBJECTIVE
To examine the taxonomic boundaries in the Stellantchasmus populations in different hosts and reveal the cryptic speciation of the Stellantchasmus in Thailand based on both morphological and molecular approaches.
METHODS
Stellantchasmus falcatus (S. falcatus) s.l. was collected from different hosts throughout Thailand. The worms were examined and measured. The nuclear ITS2 gene and the mitochondrial COI gene were used to investigate the S. falcatus s.l. from Dermogenus pusillus and Liza subviridis.
RESULTS
Stellantchasmus was one of food-borne trematode that widely distribute throughout Thailand. The comparison of S. falcatus s.l. from Dermogenus pusillus and Liza subviridis indicated a genetic divergence of nuDNA with 3.6% and mtDNA with 19.3%, respectively. Morphological characteristics were fairly different in the ratio of body size, length of prepharynx, and ratio of organ size.
CONCLUSIONS
Our results provide initial evidence that S. falcatus s.l. from different hosts tend to be a different species based on both molecular and morphological characters. Cryptic species complexes are generally found among parasites that tend to have large populations and/or rapid evolution. The degree of genetic diversity existing would suggest the practice of targeted regimes to design and minimize these lections of anthelmintic resistance in the future.
PubMed: 28237483
DOI: 10.1016/j.apjtm.2017.01.016 -
Parasites & Vectors Jan 2017Heterophyidiasis is now a major public health threat in many tropical countries. Species in the trematode family Heterophyidae infecting humans include Centrocestus...
The ribosomal transcription units of Haplorchis pumilio and H. taichui and the use of 28S rDNA sequences for phylogenetic identification of common heterophyids in Vietnam.
BACKGROUND
Heterophyidiasis is now a major public health threat in many tropical countries. Species in the trematode family Heterophyidae infecting humans include Centrocestus formosanus, Haplorchis pumilio, H. taichui, H. yokogawai, Procerovum varium and Stellantchasmus falcatus. For molecular phylogenetic and systematic studies on trematodes, we need more prospective markers for taxonomic identification and classification. This study provides near-complete ribosomal transcription units (rTU) from Haplorchis pumilio and H. taichui and demonstrates the use of 28S rDNA sequences for identification and phylogenetic analysis.
RESULTS
The near-complete ribosomal transcription units (rTU), consisting of 18S, ITS1, 5.8S, ITS2 and 28S rRNA genes and spacers, from H. pumilio and H. taichui from human hosts in Vietnam, were determined and annotated. Sequence analysis revealed tandem repetitive elements in ITS1 in H. pumilio and in ITS2 in H. taichui. A phylogenetic tree inferred from 28S rDNA sequences of 40 trematode strains/species, including 14 Vietnamese heterophyid individuals, clearly confirmed the status of each of the Vietnamese species: Centrocestus formosanus, Haplorchis pumilio, H. taichui, H. yokogawai, Procerovum varium and Stellantchasmus falcatus. However, the family Heterophyidae was clearly not monophyletic, with some genera apparently allied with other families within the superfamily Opisthorchioidea (i.e. Cryptogonimidae and Opisthorchiidae). These families and their constituent genera require substantial re-evaluation using a combination of morphological and molecular data. Our new molecular data will assist in such studies.
CONCLUSIONS
The 28S rDNA sequences are conserved among individuals within a species but varied between genera. Based on analysis of 40 28S rDNA sequences representing 19 species in the superfamily Opisthorchioidea and an outgroup taxon (Alaria alata, family Diplostomidae), six common human pathogenic heterophyids were identified and clearly resolved. The phylogenetic tree inferred from these sequences again confirmed anomalies in molecular placement of some members of the family Heterophyidae and demonstrates the need for reappraisal of the entire superfamily Opisthorchioidea. The new sequences provided here supplement those already available in public databases and add to the array of molecular tools that can be used for the diagnosis of heterophyid species in human and animal infections.
Topics: Animals; DNA, Helminth; DNA, Ribosomal Spacer; Female; Fish Diseases; Fishes; Heterophyidae; Male; Phylogeny; RNA, Ribosomal, 28S; Trematode Infections; Vietnam
PubMed: 28069063
DOI: 10.1186/s13071-017-1968-0 -
PloS One 2016Intestinal parasitic diseases occur worldwide and can cause diarrhea or gastroenteritis; however, their diagnosis is quite difficult, especially in low-endemism...
Multiplex Real-Time PCR Assay Targeting Eight Parasites Customized to the Korean Population: Potential Use for Detection in Diarrheal Stool Samples from Gastroenteritis Patients.
Intestinal parasitic diseases occur worldwide and can cause diarrhea or gastroenteritis; however, their diagnosis is quite difficult, especially in low-endemism countries. We developed a multiplex real-time PCR assay for detection of eight intestinal parasites and prospectively evaluated it for patients with gastroenteritis. The assay targeted Cryptosporidium parvum, Giardia lamblia, Entamoeba histolytica, Blastocystis hominis, Dientamoeba fragilis, Clonorchis sinensis, Metagonimus yokogawai, and Gymnophalloides seoi. Performance characteristics were evaluated based on recovery after DNA extraction, analytical sensitivity, specificity, reproducibility, cross-reactivity, and interference characteristics. Clinical performance was validated against microscopy on 123 diarrheal samples. The assay demonstrated strong correlations between DNA concentrations and Ct values (R2, 0.9924-0.9998), and had a high PCR efficiency (83.3%-109.5%). Polymerase chain reactions detected as few as 10-30 copies of genomic DNA, and coefficient of variance was 0-7%. There was no cross-reactivity to the other 54 microorganisms tested. Interference occurred only in presence of high concentrations of erythrocytes or leukocytes. This assay had a higher correct identification rate (100.0% vs. 90.2%) and lower incorrect ID rate (0.0% vs. 9.8%) when compared to microscopy. Overall, this assay showed a higher sensitivity (100.0%; 95% confidence interval [CI] of 80.5-100.0) than microscopy (29.4%; 95% CI 10.31-55.96), and the specificity levels were comparable for both methods (100.0%; 95% CI 96.58-100.0). This newly developed multiplex real-time PCR assay offers a potential use for detecting intestinal parasitic pathogens customized to the Korean population.
Topics: DNA, Protozoan; Diarrhea; Feces; Humans; Intestinal Diseases, Parasitic; Multiplex Polymerase Chain Reaction; Real-Time Polymerase Chain Reaction; Reproducibility of Results; Republic of Korea; Sensitivity and Specificity
PubMed: 27861635
DOI: 10.1371/journal.pone.0166957 -
The Korean Journal of Parasitology Aug 2016Stellantchasmus falcatus (Digenea: Heterophyidae) is first reported from Cambodia through recovery of the metacercariae from mullet fish and adult flukes from an...
Stellantchasmus falcatus (Digenea: Heterophyidae) is first reported from Cambodia through recovery of the metacercariae from mullet fish and adult flukes from an experimentally infected hamster. We purchased 7 mullets, Chelon macrolepis, in a local market of Phnom Penh, Cambodia, and each of them was examined by the artificial digestion method on May 2010. The metacercariae of S. falcatus were detected in all mullets (100%) examined, and their average density was 177 per fish. They were elliptical, 220×168 μm in average size. They were orally infected to an hamster to obtain adult flukes. Adults recovered at day 10 post infection were observed with a light microscope and a scanning electron microscope (SEM). They were small, 450×237 μm in average size, had a small oral sucker (41×50 μm), subglobular pharynx (29×21 μm), slender esophagus (57 μm), long and thick-walled expulsor (119×32 μm), spherical ovary (58×69 μm), and 2 ovoid testes (right: 117×74 μm; left: 114×63 μm). Eggs were small, yellow, and 23×12 μm in average size. In SEM observations, tegumental spines were densely distributed on the whole tegument, and single small type I sensory papillae were distributed around the lip of oral sucker. The small ventral sucker was dextrally located and had 8 type I sensory papillae on the left margin. It has been first confirmed in the present study that the mullet, C. macrolepis, is playing the role of a second intermediate host of S. falcatus in Cambodia.
Topics: Animal Experimentation; Animals; Cambodia; Cricetinae; Heterophyidae; Metacercariae; Microscopy; Parasite Load; Smegmamorpha; Trematode Infections
PubMed: 27658608
DOI: 10.3347/kjp.2016.54.4.537