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PubMed1989

A human case of Stellantchasmus falcatus infection.

A human case infected with Stellantchasmus falcatus(Heterophyidae) is reported based on the adult worms collected after praziquantel treatment. The patient is a 33-year old male residing in Seoul. For several months he experienced vague abdominal discomfort and hunger pain. Praziquantel at a single dose of 600 mg was given followed by purgation with magnesium salt, and 17 adult S. falcatus specimens were collected from the diarrheal stools. He recalled he had eaten raw flesh of several kinds of brackish water fishes. This is the 4th human case of S. falcatus infection in Korea.

Adult↗
PubMed1990

Intestinal trematodes of humans in Korea: Metagonimus, heterophyids and echinostomes.

Ten species of the trematode family Heterophyidae (Metagonimus yokogawai, M. takahashii, Heterophyes nocens, H. heterophyes, H. dispar, Heterophyopsis continua, Pygidiopsis summa, Stellantchasmus falcatus, Centrocestus armatus and Stictodora fuscatum), and 3 species of the family Echinostomatidae (Echinostoma hortense, E. cinetorchis and Echinochasmus japonicus) have been found to infect humans in Korea. Biological and epidemiological studies on the above species have shown that Metagonimus, heterophyids and echinostomes are all prevalent indigenously in Korea except H. heterophyes and H. dispar, of which the human cases were infected when they came to the Middle East. Various kinds of fish have been proven to be the source of human infection with these flukes. For example, fresh water fish such as the sweetfish, carp, loach, etc., were found to carry the metacercarial stage of M. yokogawai, M. takahashii, C. armatus, E. hortense, E. cinetorchis and/or E. japonicus. Brackish water fish such as the mullet, perch and goby, were verified to be the second intermediate host of H. nocens, H. continua, P. summa, S. falcatus and/or S. fuscatum. Among the intestinal flukes, M. yokogawai is the most prevalent species in Korea.

Animals↗
PubMed1993

Mucosal mast cell responses to experimental Metagonimus yokogawai infection in rats.

Intestinal mucosal mast cell (MMC) responses were studied in rats experimentally infected with Metagonimus yokogawai (Digenea: Heterophyidae). Twenty Sprague-Dawley rats were fed each 2,500 metacercariae isolated from the sweetfish and sacrificed on the week 1, 2, 3 and 4 post-infection (PI). Recovery of worms was performed from the small intestine of each rat. To visualize the MMCs, duodenal and jejunal (upper, middle and lower) tissue sections were made and stained with alcian blue/safranine-0. The average worm recovery rates were 16.2% and 13.8% on the week 1 and week 2, respectively, but they decreased rapidly to 4.1% and 4.2% on the week 3 and week 4 PI, respectively, which indicate spontaneous worm expulsion after the week 2. The MMC number in the infected rats was, compared with uninfected controls, significantly increased in the whole small intestine, through the whole period of observation. The peak level of mastocytosis was observed on the week 3 PI. It is strongly suggested that MMCs might be involved in the expulsion process of flukes from the rat intestine.

Animals↗
PubMed1999

An incidental case of human Heterophyes nocens infection diagnosed by sectional morphology in a biopsy specimen of the small intestine.

A case of human infection with Heterophyes nocens (Heterophyidae) was incidentally found in a biopsy specimen of the Meckel's diverticulum at the upper part of the small intestine. The patient was a 58-year-old man living in a rural area of Talsonggun, Kyongsangbuk-do. He had gastrointestinal symptoms such as epigastric pain, indigestion, and abdominal discomfort for 3 months, and severe diarrhea, abdominal pain, and vomiting for about 1 month before hospitalization. Endoscopy of the upper part of the small intestine revealed a Meckel's diverticulum, and it was excised and histopathologically examined. Three adult flukes were incidentally found sectioned in the mucosa, and they were identified as H. nocens. The patient had a history of eating raw mullets at a fish market in Pusan 6 months ago, and the mullets were presumed to be the source of infection. This case brings a considerable interest in that specific diagnosis of heterophyid infections could be done by sectional morphology of the worms.

Animals↗
PubMed1999

Prevalence of trematode metacercariae in cyprinoid fish of Ban Pao district, Chiang Mai Province, northern Thailand.

The prevalence of trematode metacercariae in natural cyprinoid fish was carried out in Ban Pao district, Chiang Mai Province, northern Thailand. Fish were collected from both man-made water reservoirs and natural sources during July 1996-May 1997. Nine species of cyprinoid fish harbored the metacercariae of Opisthorchis viverrini and small intestinal flukes of the family Heterophyidae, ie Haplorchis taichui, H. pumilio and Centrocestus spp. Metacercariae of H. taichui were found approximately 384 times more than O. viverrini. Among the fish collected, Puntius leiacanthus contained the highest number of metacercariae of H. taichui (182 metacercariae/fish) whereas P. orphoides contained the highest number of metacercariae of O. viverrini (1.4 metacercariae/fish). Metacercariae of H. taichui found in this area were year-round, with the highest and lowest incidence rates being in winter and rainy season, respectively. The difference between H. taichui and O. viverrini with respect to their prevalences are discussed.

Animals↗
PubMed2001

Intestinal heterophyidiasis: an emerging food-borne parasitic zoonosis in southern Philippines.

Heterophyidiasis is an infection of the small bowel by minute intestinal flukes of the genus Heterophyes or related members of the family Heterophyidae. To provide a better understanding of this rarely reported condition, this study attempted to determine the infection rate, intensity of infection as well as the clinical spectrum of heterophyid infection. A stool survey was conducted in barangay San Isidro, Monkayo, Compostela Valley. Thirty-six percent of patients with history of bowel disturbance (abdominal discomfort/pain and/or diarrhea) in the past 4 weeks were found to have heterophyidiasis. All age groups were infected, with the youngest patient being 1 year 7 months of age, while the oldest patient was 73 years of age. Prevalence was highest in the 15 to 30 years old group at 55.3%. The most common clinical manifestations of heterophyidiasis were signs and symptoms of acid peptic or peptic ulcer disease. Early diagnosis and treatment are important to ensure prompt resolution of heterophyid infection, hence, decreased morbidity and decreased chances for complications like heart or brain involvement. Proficiency of laboratory staff should be enhanced to ensure accurate diagnosis which will then make appropriate treatment possible.

Adolescent↗
PubMed1991

Intestinal trematodes infecting humans in Korea.

Sixteen species of intestinal trematodes have been recovered from humans in Korea. They include 10 species of the family Heterophyidae (Metagonimus yokogawai, M. takahashii, Heterophyes nocens, H. heterophyes, H. dispar, Heterophyopsis continua, Pygidiopsis summa, Stellantchasmus falcatus, Centrocestus armatus, and Stictodora fuscatum); one species of Diplostomidae (Fibricola seoulensis); three species of Echinostomatidae (Echinostoma hortense, E. cinetorchis, and Echinochasmus japonicus); one species of Plagiorchiidae (Plagiorchis sp.), and one species of Gymnophallidae (Gymnophalloides sp.). Biological and epidemiological studies have shown that all of these species are endemic to Korea except H. heterophyes and H. dispar, which were imported from the Middle East, and Plagiorchis sp., which has not been found in Korea. Several fresh water fish were found carrying metacercarial stages of M. yokogawai, M. takahashii, C. armatus, E. hortense, E. cinetorchis and E. japonicus. Brackish water fish were found to be the second intermediate host of H. nocens, H. continua, P. summa, S. falcatus, and/or S. fuscatum. Terrestrial snakes were the second intermediate (or paratenic) host of F. seoulensis. Among these intestinal flukes, M. yokogawai is the most common one in Korea.

Animals↗
PubMed1995

Heterophyid eggs in human stool samples in Assam: first report for India.

Two cases from a Muslim family in upper Assam were found to pass trematode eggs morphologically similar to the members of the family Heterophyidae Odhner, 1914. The eggs characteristically yellowish brown in colour, ovoid, have a thick shell and are operculate. They measured 31.5 +/- 2.0 um SD x 22.4 +/- 1.9 um SD with well developed miracidium. This is the first record of human heterophyid infection from India.

Adult↗
PubMed1997

Metacercariae isolated from cyprinoid fishes in Khon Kaen District by digestion technic.

Several kinds of fresh-water fishes collected from natural water resources in Khon Kaen District were digested with 0.25% pepsin A to obtain the infective stage or metacercariae of fish-borne trematodes. Most of them harbored at least 3 species of trematodes. Two families of medical trematodes, i.e., Family heterophyidae and Family Opisthorchiidae, were isolated. The heterophyid flukes consisted of Haplorchis taichui, H. pumilio and Centrocestus formosanus. Opisthorchis viverrini was the only parasite of the Family Opisthorchiidae found in these fish. Among these four species, H. taichui was predominant and found in all kinds of fish examined, especially Hampala dispar.

Animals↗
PubMed1998

Experimental host of Stellantchasmus falcatus.

The purpose of this research was to determine the incidence and intensity of infection in experimental host of minute intestinal trematode, Stellantchasmus falcatus (family Heterophyidae). Experimental hosts consisting of uninfected mice (Mus musculus) and one-day-old chicks (Gallus gallus domesticus) were orally force fed with a hundred metacercariae of S. falcatus obtained from the body cavity of the freshwater fish Dermogenys pusillus. The worms, then, were checked from 24 hours to 30 days post-infection. The heterophyid flukes were distributed in the ileum and jejunum of the chicks and small intestine of mice with 70% (21/30) and 80% (24/30) of incidence and intensity of infection range from 1-44 (24.6) and 1-67 (7.8), respectively. The body size of S. falcatus at 24 hours; was 0.1-0.15 (0.13) x 0.29-0.39 (0.33) mm in chicks and 0.14-0.17 (0.15) x 0.29-0.32 (0.3) mm in mice. The maximum length and width of the worms were found within 5 days post-infection, of 0.2-0.25 (0.22) x 0.49-0.62 (0.55) in chicks and 0.19-0.22 (0.2) x 0.38-0.52 (0.44) mm in mice. Developing egg was found in the second day after infection and the number of egg increase with the age of the parasite. Embryonated eggs were recovered in the feces of mice 9 day post-infection. S. falcatus infection in the other experimental host was done in rat (Rattus norvegicus), but rats were fed with whole number of metacercariae which found in a body cavity of fish, D. pusillus. The results appear to be the same as in the chicks and mice.

Animals↗
PubMed2005

Molecular-genetic analyses reveal cryptic species of trematodes in the intertidal gastropod, Batillaria cumingi (Crosse).

Cryptic species of the digeneans, Cercaria batillariae (Heterophyidae) and an undescribed philophthalmid, were detected using polymerase chain reaction-based restriction fragment-length polymorphism methodology and sequence analyses. These digeneans were all collected from the same species of gastropod first intermediate host, Batillaria cumingi (=Batillaria attramentaria). The mitochondrial cytochrome oxidase subunit 1 gene (approximately 800bp) and nuclear internal transcribed spacer 1 gene (approximately 400bp) were used for species level discrimination. Restriction fragment-length polymorphism analyses of cytochrome oxidase subunit 1 gene showed that C. batillariae included 10 distinguishable fragment patterns, and the philophthalmid included five patterns. On the basis of subsequent sequence analyses, the restriction fragment length polymorphism patterns of C. batillariae were grouped into eight phylogenetically distinct lineages and those of the philophthalmid into three phylogenetically distinct lineages. There was no evidence of gene flow among the different lineages due to the lack of heterozygosity within the observed internal transcribed spacer 1 gene fragment patterns. This suggests that all of these lineages are different species. Most of these species were widespread, but some exhibited restricted geographic distributions. We discuss the implications of these findings for host specificity of these trematodes. These results demonstrate the utility of genetic analysis to distinguish species of morphologically similar trematodes. Hence, trematode species diversity may often be underestimated when species identifications are limited to morphological features.

Animals↗
PubMed2006

Immunology and pathology of intestinal trematodes in their definitive hosts.

This review examines the significant literature on the immunology and pathology of intestinal trematodes in their definitive hosts. We emphasize information on selected species in six families for which the literature on these topics is extensive. The families are Brachylaimidae, Diplostomidae, Echinostomatidae, Gymnophallidae, Heterophyidae, and Paramphistomidae. For most of these families, coverage is considered under the following headings: (i) background; (ii) pathology of the infection; (iii) immunology of the infection; (iv) immunodiagnosis; and (v) human infection. Some of these heading have been subdivided further, based on the literature available on a particular topic. Following this coverage, we include a final section on the important topical literature on selected trematodes in families other than the six mentioned above.

Animals↗
PubMed2002

Food-borne intestinal trematode infections in the Republic of Korea.

A total of 19 species of food-borne intestinal trematodes have been reported in humans in the Republic of Korea. They include 12 species of the Heterophyidae, Metagonimus yokogawai, M. takahashii, M. miyatai, Heterophyes nocens, H. heterophyes (imported), H. dispar (imported), Heterophyopsis continua, Pygidiopsis summa, Stellantchasmus falcatus, Centrocestus armatus, Stictodora fuscata, and S. lari; four species of the Echinostomatidae, Echinostoma hortense, E. cinetorchis, Echinochasmus japonicus, and Acanthoparyphium tyosenense; and one species each of the Neodiplostomidae, Neodiplostomum seoulense, Plagiorchiidae, Plagiorchis muris, and Gymnophallidae, Gymnophalloides seoi. Fresh water fish harbor the metacercarial stage of M. yokogawai, M. takahashii, M. miyatai, C. armatus, E. hortense, E. cinetorchis, E. japonicus, or P. muris. Brackish water fish serve as the second intermediate hosts for H. nocens, H. continua, P. summa, S. falcatus, S. fuscata, and S. lari. Brackish water bivalves are the source of infection with A. tyosenense. Tadpoles and frogs are the second intermediate hosts for N. seoulense, but the major source of human infection is the grass snake Rhabdophis tigrina, a paratenic host. The metacercariae of G. seoi are observed in oysters. The natural definitive hosts are, in most cases, mammals such as rats, cats and dogs. However, several species (C. armatus, S. lari, E. japonicus, A. tyosenense, and G. seoi) have birds as natural definitive hosts. Host-parasite relationships, pathogenesis and pathology, immunity, clinical aspects, differential diagnosis, treatment, prevention and control of these intestinal trematodes are briefly discussed.

Animals↗
PubMed1997

Centrocestus formosanus: surface morphology of metacercaria, adult and egg

The surface morphology of metacercariae isolated from Puntius spp., adult worms from infected hamsters and eggs of Centrocestus formosanus (Digenea: Heterophyidae) were studied using scanning electron microscopy. It was found that the surfaces of the metacercariae and adult worms were closely similar in appearance. The oral sucker was surrounded by a circumoral expansion with two rows of 32 spines (16 spines each). The ventral sucker, with six large nonciliated papillae on the lip, and the genital opening were located mid-ventrally. The excretory pore was terminal. The body surface was covered with pectinate scale-like spines of varying sizes. The scales in the middle area were larger than those in the anterior and posterior parts of the body. Sensory papillae, mostly uniciliated, were present in greater abundance at the anterior region of both stages. However, morphological variations were observed among the adults depending on the age of the worms. At 4 weeks, the oral sucker and circumoral expansion were cobblestone-like in structure and the grooves of spines split compared with their smooth surfaces at 10 days. In addition, the ventral sucker became depressed and its large papillae on the lip disappeared at 10 weeks post infection. Multiciliated papillae were also present in 10-week old worms. Each egg of this parasite possessed a prominent operculum and a latticed design on the egg shell.

Journal Article↗
PubMed1977

Pholeter anterouterus Fischthal & Nasir, 1974 (Digenea: Opisthorchiidae) redescribed, together with remarks on the genera Pholeter Odhner, 1914 and Phocitrema Goto & Ozaki, 1930 and their relationship to the centrocestine heterophyids.

Photoleter anterouterus Fischthal & Nasir, 1974, from Pelecanus occidentalis Linnaeus and Pelecanus erythrorhynchos Gmelin from Florida, USA and the ventro-genital complexes of Photeleter gastrophilus (Kossack, 1910) from Delphinus delphis Linnaeus from Queensland, Australia and of Phocitrema fusiforme Goto & Ozaki, 1930 from Alopex lagopus (Linnaeus) and Phoca vitulina Linnaeus from Alaska are redescribed. The genus Photoleter Odhner, 1914 is emended and compared with Phocitrema Goto & Ozaki, 1930 and both genera are compared with members of, and as a result transferred from the family Opisthorchiidae Looss, 1899 to, the subfamily Centrocestinae Looss, 1899, family Heterophyidae Odhner, 1914.

Animals↗
PubMed1992

Larval stages of medically important flukes (Trematoda) from Vientiane province, Laos. Part II. Cercariae.

The cercariae of five flukes, which are potential human parasites, Opisthorchis viverrini (family Opisthorchiidae), Haplorchis taichui (Heterophyidae), Schistosoma spindale (Schistosomatidae), Fasciolopsis buski, and Fasciola gigantica (Fasciolidae) were found in freshwater snails from Laos. The cercariae of the above species, recorded in Laos for the first time, are illustrated and their morphology is briefly described. The snail Helicorbis umbilicalis represents a new intermediate host of F. buski. The occurrence of medically important snails in the Vientiane province will also be discussed.

Animals↗
PubMed2003

Identification of trematode cercariae carrying Neorickettsia risticii in freshwater stream snails.

We provide evidence of Neorickettsia (Ehrlichia) risticii Holland, the agent of Potomac horse fever, in trematode larval stages found in aquatic snails and insects collected from a stream in Korea, using nested polymerase chain reaction (PCR) and sequence analysis of the 16S rRNA gene fragment amplified from several cercaria species. It was observed that of 423 (13.1%) of 3,219 snails infected with cercariae, 77 (20.8% of the 371) were infected with N. risticii. Five families of trematode cercariae, Schistosomatidae, Echimostomatidae, Heterophyidae, Microphallidae, and Acanthocopidae were identified morphologically within Semisulcospira libertina, Radix auricularia coreana, and S. gottschei snails. Echinostoma cinetorchis, E. hortense, and Metagonimus sp. were identified based on both the cercarial morphology as well as by phylogenetic analysis of the amplified 18S rRNA gene sequences. Adult aquatic insects were also collected from the same sites and were sorted into five species, Ischnura asiatica in Coenagrionidae and Calopteryx japonica, Sympetrum darwinianum, Symptrum eroticum, and Symptrum parvulum in Calopterygoidae. One thousand and two hundred eighty five metacercariae (classified into groups A through F) were isolated from 310 adult aquatic insects, and the average number of metacercariae per aquatic insect was 4.1. However, there was no amplification of N. risticii from these metacercariae.

Anaplasmataceae Infections↗
PubMed2002

Component community of larval trematodes in the mudsnail Hydrobia ventrosa: temporal variations in prevalence in relation to host life history.

Temporal variations in the prevalence of larval trematodes in the short-lived prosobranch mudsnail Hydrobia ventrosa (Montagu) were investigated in relation to host life history and season for 4 successive years in temperate windflats of the southern Baltic Sea. The component community of trematode larvae in H. ventrosa comprises at least 10 species; families (and species) represented include Notocotylidae (1), Echinostomatidae (1 or 2), Heterophyidae (2), Monorchidae (1), Microphallidae (3 or 4), Psilostomatidae (1), and Hemiuridae (1). The notocotylid Paramonostomum alveatum was the most prevalent species, followed by the microphallids Maritrema subdolum and Microphallus sp. Trematode prevalence in H. ventrosa fluctuated seasonally. Prevalence usually peaked in summer between July and September-October and decreased in late winter-early spring. This seasonal change is chiefly explained by the life history patterns of the semelparous snail host. Hydrobia ventrosa has a maximum life span of about 2 yr and reproduces between June and November of its second calendar year. The first trematode infections appeared annually in May when the most abundant cohort of H. ventrosa, the second-calendar-year snails, mature. The prevalence continued to increase until August-September, throughout the reproductive period of the second-calendar-year snails, Prevalence decreased during winter, when most of the second-calendar-year snails died after reproduction. On the basis of longterm laboratory experiments, it has been shown that the late autumn-winter mortality was not the result of trematode infections. Seasonal patterns of prevalence were similar among the trematode species except for the monorchid Asymphylodora demeli, the only one using fish definitive hosts. Species-specific differences in the seasonal occurrence of prepatent infections and the predominance of certain larval stages in winter are interpreted as different strategies of the trematode species to survive the harsh winter conditions, or to survive the death of the first intermediate host in autumn-winter, or both.

Animals↗