• Parasites, Hosts and Diseases
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• v.58 no.4
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• pp.475-479
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• 2020

Tegumental and excretory-secretory proteins are reported as diagnostic antigens for human opisthorchiasis. Rhophilin associated tail protein1-like (OvROPN1L) protein of Opisthorchis viverrini sperm tail showed potential as a diagnostic antigen. The OvROPN1L recombinant fragments were assayed for diagnostic antigenicity for human opisthorchiasis using indirect ELISA. The strongest antigenic region was a N-terminus peptide of M1 - P56. One synthetic peptide (P1, L3-Q13) of this region showed the highest antigenicity to opisthorchiasis. Sera from other parasitic infections including Strongyloides stercoralis, hookworm, Taenia spp, minute intestinal flukes, Paragonimus spp showed lower reactivity to P1. Peptide P1 is located in the disordered N-terminus of ROPN1L supporting its suitability as linear epitope. In the Platyhelminthes the N-terminal sequence of ROPN1L is diverging with taxonomic distance further suggesting that peptide P1 has potential as diagnostic tool in the genus Opisthorchis/Clonorchis. It should be further evaluated in combination with peptides derived from other O. viverrini antigens to increase its diagnostic power.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.43-50
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• 1984

Two cases of human infection by Stellantchasmus falcatus (Heterophyidae) were identified by collection of adult worms during the treatment of some tapeworm infections in Korea. The cases were 24 (Case 1) and 55-year old (Case 2) males residing in Seoul. The Case 1 had gastrointestinal troubles such as diarrhea and abdominal pain, and heart problems such as palpitation and arrhythmia, revealing the eggs of Diphyllobothrium latum in the feces. The Case 2 complained indigestion and discharge of tapeworm (Taenia saginata) segments. Praziquantel at the dose of 15-20mg/kg body weight and 30 g magnesium salt were given to them for treatment of the tapeworm infections and the discharged strobilae were identified. However, concommitantly with the tapeworms, 188 and 5 specimens of S. falcatus were collected from Case 1 and Case 2 respectively through stereomicroscopy of the diarrheal stools. The Case 1 was infected also with 3 other kinds of heterophyid flukes. They said to have eaten raw brackish water fish such as mullets which are considered to be the source of heterophyid fluke infections.

• Parasites, Hosts and Diseases
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• v.42 no.1
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• pp.41-44
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• 2004

The pond smelt Hypomesus olidus and minnow Zacco platypus were collected from the Soyang and Daechung Lakes in January 2003, and their metacercarial infections was examined by the muscle compression and artificial digestion techniques. In the Soyang Lake, 161 metacercariae of Clonorchis sinensis (0.35 per fish) were harvested from 459 pond smelts examined. Also, 13 metacercariae of C. sinensis (0.43 per fish), 1 of Metagonimus sp., 4 of Echinostoma sp., 148 of Centrocestus armatus and 44 unidentified species were collected from 30 minnows. In the Daechung Lake, 369 metacercariae of C. sinensis (3.69 per fish) and 51 unidentified species were recovered from 100 pond smelts. The metacercariae of C. sinensis were fed to experimental rats, in which the adult flukes were identified. The pond smelts and minnows collected from the Soyang and Daechung Lakes were verified to be the second intermediate hosts and the sources of human C. sinensis infection.

• Parasites, Hosts and Diseases
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• v.58 no.1
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• pp.67-72
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• 2020

Human infection with Echinostoma aegyptica Khalil and Abaza, 1924 (Trematoda: Echinostomatidae) is extremely rare. In this study, we confirmed E. aegyptica infection in 5 riparian residents living along the Mekong River in Savannakhet Province, Lao PDR. The patients revealed eggs of Opisthorchis viverrini/minute intestinal flukes, echinostomes, and other parasites in fecal examinations using the Kato-Katz technique. Following treatment with praziquantel 30-40 mg/kg and pyrantel pamoate 10-15 mg/kg in a single dose and purging with magnesium salts, adult specimens of various helminth species were collected. Among the trematodes, echinostome flukes of 4.5-7.6 mm in length (n = 134; av. 22.3 specimens per case) were of taxonomic interest and subjected in this study. The flukes were morphologically characterized by having total 43-45 collar spines arranged in 2 alternating rows (corner spines usually 5 on each side) and compatible with previous descriptions of E. aegyptica. The patients were mixed-infected with other helminths, so specific clinical manifestations due to this echinostome fluke were difficult to determine. The present paper describes for the first time human E. aegyptica infections in Lao PDR. This is the second report of human infection (2nd-6th cases) with E. aegyptica in the world following the first one from China.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.6-10
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• 1983

A study of infestation patterns for larval trematodes from fresh-water fish and brackish-water fish was carried out during the period from June to October in 1982. They were collected by netting, asking with rod and lino, and using the a bait of crushed oil cake in a transparent plastic bowls at the three localities, Daebon-dong, Kugil-dong, and Hoam-dong in the river Taechong, Kyungpook Province, Korea. Five species of fresh-water fish, the crussian carp, Carassius carassius Linnaeus, the bullhead, Coreobagrus brfvicorpus Mori, the fat minnow, Morose oxycephalus (Bleeker) , the flat bitterling, Paracheilognathus rhombea (Temminck et Schlegel) , and the catfish, Parasilurus asotus (Linnaeus), and two kinds of brackish-water fish, the grey mullet, Mugil cephalus(Linnaeus) and the sweet-fish, Plecoglossus aztivelis (Temminck et Schlegel) were examined. Four species of the metacercariae, Exorchis eviformis, Metacercaria hasegawai, Metorchis orientalis and undetermined larvae were found. Of these, the encysted larvae of the human intestinal fluke, Metagonimus yokegawai, were found from three kinds of fresh-water fish, the crussian carp, the bullhead and the fat minnow and one species of brackish-water fish, the sweets;sh and the infestation rates for the larvae varied appreciably from fish to fish. The intensity of infestation with the Metagonimus larvae in the three species of fresh-water fish was low, and the average number of the larvae per gram of flesh varied from 0.5 to 0.2. By comparison, the brackish-water fish wqs more heavily infested and the mean number of cysts per gram of flesh in Plecoglossus altivelis was 109.2. It was foung that infection with Metagonimus yokogawai os caused by consuming raw fresh-sater fish and brackish-water fish caught in the river Taechong, Kyungpook Province, Korea.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.24-32
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• 1985

The worm development and egg laying pattern of Echinostoma hortense (Trematoda; Echinosto-matidae) were studied in albino rats and the brief clinical course was observed in human volunteers. A total of 21 rats were infected with 20~69 metacercariae each and two humans were with 7 and 27 metacercariae, which were collected from the loaches. For recovery of worms, the rats were sacrificed at irregular intervals from the 6th to 150th day after infection and the human volunteers were treated with praziquantel and purged with magnesium salt on the 26~27th day. The stools of the rats and humans were examined for the eggs. The results were as follows: 1. The worm recovery rate from the rats was not affected by the increase of infection time but varied individually; 9.1~50.0% (31.1 % in average). From humans, 14.3% and 37.0% (32.4% in average) of challenged were recovered. 2. In the rats, it was revealed that the worms rapidly grew for the first 14 days to become 7.59mm in average length and 1.17mm in average width but the growth became much slower thereafter until the 150th day; 7.95mm in length on the 21 th day, 9.04mm on the 28th day, 10.21mm on the 49th day and 12. 62mm on the 150th day. During the early stage of infection, the growth of genital organs (male or female) was expressed as sigmoid curves whereas non-genital organs (such as suckers) was simply as straight lines. 3. The prepatent period of this fluke was 10~12 days in the rats and 16~17 days in men. After the start of oviposition, the egg production by the worms remarkably increased, reached maximum on the 32~33th day, followed by decrease thereafter. The maximum value of E.P.G./worm was 390. 4. The major subjective symptoms in human volunteers were abdominal pain and diarrhea during the early stage of infection. The results show that human is as susceptible as the rats to E. hortense infection and the amount of egg production in the rats is greatly affected by the age of worms.