• Parasites, Hosts and Diseases
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• v.23 no.2
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• pp.203-213
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• 1985

The in situ posture of anterior body of Metagonimus yokogawai was observed in experimental metagonimiasis of dog. The metacercariae were collected from naturally infected sweetfish by peptic digestion; a total of 8 dogs was orally infected with 10,000 metacercariae respectively. Two dogs were killed on 3 days, 9 days, 4 weeks and 10 weeks after the infection. The postures of worms in histological section of small intestine and of whole worms collected from the fixed intestinal mucosa were examined by light and scanning electron microscope. The results were summarized as follows: 1. The recovery rates of worms were 42.6% on 3 days, 55.0% on 9 days, 33.2% on 4 weeks and 9. 8% on 10 weeks after the infection respectively. 2. In histological sections of small intestine, most of worms were found at intervillous spaces as ovoid sections of posterior body. However, many worms, especially in 3 day-old worms, revealed protruded anterior body in glandular lumens of crypt. Some sections of anterior body were bifurcated or sacculated. 3. The worms collected from fixed intestinal mucosa under dissecting microscope exhibited a variety of postures. Many worms showed flat shapes with a concavity or curvatures. However, in many worms, the anterior body made a single or multiple protrusions. 4. By SEM observation of protruded anterior body, a longitudinal groove was found. 5. The frequency of worms with protruded anterior body decreased in 9 days, 4 weeks and 10 weeks than in 3 day-old worms. The above findings indicated that the anterior body of juvenile and adult M. yokogawai protruded to lumens of glandular crypt by folding their lateral portions to make a reversible tubelike structure. Frequent multiple protrusions were considered to be made to adapt the microniche of glandular crypts of dog intestine.

• Parasites, Hosts and Diseases
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• v.21 no.2
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• pp.193-204
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• 1983

The Jinyang Lake is dammed up Nam River, and surrounded by Jinju city and four counties; Jinyang, Sanchong, Hading, and Sachon in kyongsang-Nam-Bo, Korea. The areas around this man-made lake have been known as an endemic focus of clonorchiasis in Korea. The present study was first aimed to know the distribution of freshwater mollusks including medically important snails, and larval trematodes shed from Parafossarulus manchouricus and Semisulcospira libertina. In addition to above studies, water analyses in each snail habitat were carried out in order to figure out a part of their environmental factors. This malaco-ecological survey was done at the sirs areas around upper, middle and lower parts of the lake for 4 months, August-November, 1983. Total nine species of freshwater mollusks were collected throughout the study: 4 species of gastropods: Semisulcospira libertina, Cipangopaludina chinensis, Parafossarulus manchouricus and Radin auricularia, and 5 species of bit.alves; Unio dcuglasiae, Ancdonta woodiana, Lamprotula gottschei, Corbicula yuminea and Limncperma lucustris. Out of nine species of freshwater mollusks, three species of gastropods; S. Zibertina, p. manchouricus and R. auricularia were medically important in terms of the transmission of digenetic trematodes to humans. P. manchouricus and R. auricularia were mainly collected from the shallow ponds and the irrigation channels with the muddy basin, but S. libertine and the bivalves were only collected from the stream of Nam River where the gravels and rocks were dominant. The levels of dissolved oxygen (D.O.) and biochemical oxygen demand \(B.O.D._5)\ of the water specimens sampled from the study areas ranged from 6.0 to 9.6 ppm and from 0.4 to 1.6 ppm respectively. As a result, it is considered that water system around the Jinyang Lake might be relatively clean without any heavy pollution of aquatic microorganisms and organic materials during the period of this study. On the other hand, eight metalic constituents from the water samples were also assayed, and all metalic ions detected were remarkably low below the legal criteria. However, calcium ion in the water samples from the habitats of P. manchouricus was considerably higher than others. Infection rates of digenetic trematodes in the snails were 6.9% in P. manchouricus and 4.8% in S. libertine, respectively. P. manchouricus snails harboring with thc cercariae of Clonorchis sinensis were only 0.14% among the snails examined, and other trematode cercariae except cercaria of C. sinensis were: furcocercus cercariae, cercaria of Loxogenes liberum type I and II. S. libertine snails parasitized with the cercariae of Metagonimus yokogawai were 1, 5% out of the snails examined, and no cercaria of Paragonimus westermani was found in S. libertine snails in the present study. Digenetic trematode cercariae other than M. yokogawai observed in S. libertina snails were: Cercaria yoshidae (B type) , Cercaria cristata, Cercaria innominatum, Cercaria of Centrocestus formosanus and Cercaria nipponensis.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.109-115
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• 1984

In order to estimate the recent patterns of intestinal helminth infections among the residents in Taegu City, Korea, a survey based on discovery of helminth eggs by formalin-ether sedimentation and modified Graham's scotchtape anal swab techniques, were performed during the period from March to September in 1983. A total of 1, 697 fecal specimens were collected from 854 male and 843 female residents from 5 village (Dong), each of whom were selected randomly to represent 1, 000 persons referred to the census in 1982. Among the specimens examined, one or more species of helminth parasites were found in 473, revealing the overall positive rate of 27.9 per cent. Of them, Trichuris trichiura was found most frequently, in 13.2 percent, followed by Enterobius vermicularis in 7.0 per cen t. Hookworm was the least prevalent. The sex-specific rate of overall helminth infections was a little higher in females than in males, while in cases of Clonorchis sinensis, Metagonimus yokogawai and Taenia species, the infection rates in males was higher than in females. T. trichiura was most prevalent in the 20~29 age group and showed about the same prevalence in males and females of all age groups. C. sinensis infection rate increased with age while those of Ascaris lumbricoides decreased. Single infections were 82.5 per cent of all positive cases. Of these, T. trichiura revealed the highest prevalence in 31.7 per cent, followed by E. vermiculasis in 20.1 per cent and A. lumbricoides in 14.8 per cent. Of the double infections, the percentage of T. trichiura in combination with other intestinal helminths was higher than that of A. lumbricoides. It was concluded that although the infection rates of intestinal helminths among the residents in Taegu City, Korea is still high, eradication of these parasitic diseases seems to be possible with twice-a-year administration of specific anthelmintics, in combination with extensive public health education and improvement of the dietary life.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.213-220
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• 1990

The employees at the Pohang industrial area, where Clonarchis sinensis has been known to be endemic along the Hyungsan River, were examined parasitologically for clonorchiasis and a part of the infected cases were surveyed with a questionaire to outline the recent infection status of C. sinensis and epidemiological parameters in the area. Total of 3, 180 cases were tested by intra- dermal inoculation of C. sinensis antigen (Green Cross Co., Korea), and 834(26.2%) were found positive. Out of the positive cases, 598 were subjected to (ecal examination for helminth ova. The examination revealed 129(21.6%) ova Positive cases of C. sinensis, and Trichuris trichiura 1.7%, Ascaris lumbricoides 0.3%, and Metagonimus yokogawai 0.2%. The questionaire analysis showed some significant difFerences between the infected and non-infected(control) groups. The infected cases were less educated than the control, and they lived at the closer area to the river, and most of them lived there over 20 years. Also they preferred eating raw fresh water fish. Most of the detected cases were treated with prasiquantel and found negative for the eggs in 85.3% of them 1 year after the treatment. The present data reveal markedly decreased endemicity of clonorchiasis compared with previous prevalence rates but still clonorchiasis is endemic in the Hyungsan river basin. A comprehensive measure including case detection, treatment and education for parasite control should be applied to control clonorchiasis in such endemic areas.

• Biomedical Science Letters
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• v.2 no.2
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• pp.267-274
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• 1996

This study was performed to observe the present status of intestinal parasitic infections among the children in Iksan, Jeonbuk, Korea. During the period from February to June 1996, total 510 fecal samples(male 276, female 234) were collected and examined by formalin-ether sedimentation technique and trichrome stain for intestinal helminths and protozoan cysts. Of 510 samples examined, 62(12.2%) were positive for intestinal parasites. Helminth egg positives were 3(0.6%), and protozoan cyst positives were 59(11.6%). The female group showed higher positive rate(13.2%) than males(11.2%), and the highest positive rates were observed in 7 age group(17.5%), and lowest positive rates were 4 age group(9.5%). 3 species of helminths egg and 6 species of protozoan cyst were detected; Metagonimus yokogawai 0.4%, Enterobius vermicularis 0.2%, Trichuris trichiura 0.2%, Endolimax nana 4.1%, Entamoeba coli 3.9%, Ciardia lamblia 2.0%, Entamoeba histolytica 1.4%, Iodamoeba butschilii 0.8%, and Chilomastix mesnili 0.4%, respectively. In 3 helminth egg positive cases, single infection was 2(66.7%), and double infection 1(33.3%), among 59 protozoan cyst positives, single infection was 54(91.5%), and double infection was 5(8.5%). The highest positive rate of protozoan cyst was 7 age group(14.3), and lowest positive rate was 4 age group(9.5%).

• Parasites, Hosts and Diseases
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• v.54 no.4
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• pp.497-502
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• 2016

To know the infection status of zoonotic trematode metacercariae in brackish water fish, we surveyed mullets collected from 18 coastal areas in the Republic of Korea. The metacercariae of Pygidiopsis summa were detected in 236 (68.2%) out of 346 mullets examined. They were found in mullets from 15 areas except for those from Boseong-gun (Jeollanam-do), Pohang-si, and Uljin-gun (Gyeongsangbuk-do). Especially in mullets from Taean-gun (Chungcheongnam-do) and Geoje-si (Gyeongsangnam-do), their prevalences were 100% and 95.5%, and the average metacercarial density was more than 1,000 per fish. They were also detected in mullets from 3 coastal lakes, Gyeongpoho, Songjiho, and Hwajinpoho, in Gangwon-do, and their average densities were 419, 147, and 672 per infected fish, respectively. The metacercariae of 5 other heterophyid species, including Heterophyes nocens, Heterophyopsis continua, Metagonimus sp., Stictodora fuscata, and Stictodora lari, were found in the mullets examined. The metacercariae of H. nocens were detected in 66.7, 100, 28.6, 81.6, 3.9, 61.5, and 27.3% of mullets from Muan-gun, Shinan-gun, Haenam-gun, Gangjin-gun, and Boseong-gun (Jeollanam-do), Hadong-gun, and Geoje-si (Gyeongsangnam-do), and their metacercarial intensities were 64, 84, 119, 99, 1, 24, and 24 per fish infected, respectively. From the above results, it has been confirmed that P. summa metacercariae are heavily infected in mullets from coastal areas of Korea. It is suggested that residents who frequently consume raw mullet dish can be easily infected with heterophyid flukes.

• The Korean Journal of Malacology
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• v.2 no.1
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• pp.13-25
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• 1986

One of the most medically important snail species of Korea is Semisulcospira spp., a member of the freshwater prosobranch family pleuroceridae. The parasites that these snails transmit to humans are mainly Paragonimus westermani and Metagonimus yokogawoi. On the other hand, Semisulcospira snails are edible as a foodstuff in Korea. The present study was first aimed to detect out residual pesticides in the snails collected at the endemic and non-endemic areas of paragonimiasis in Korea and to make relationship to the detectability of larval trematodes shed from the snails. In addition, water specimens from the habitats where the snails were collected were sampled and analysed to elucidate environmental conditions of the habitats. This malaco-ecological survey was done at 7 endemic and 3 non-endemic areas of paragonimiasis for about more than 2 years, May, 1984 through October, 1986. All the water smaples both from the endemic and non-endemic areas of paragonimiasis showed normal ranges of the criteria of upper freshwater streams, with lower B.O.D. (0.4~2.0 ppm) and higher D.O. values (9.5~11.0 ppm) than those in the large river systems Infection rate of digenetic trematodes in total snails collected was 6.7%, but no Paragonimus cercaria was detected out at all even in the endemic areas of paragonimiasis. The ecological factors affecting Paragonimus larvae in the snails were also discussed. A total of 9 chlorinated hydrocarbon pesticieds was targeted to detect out from the tissues of snails. Out of 9 pesticides, aldrin, beta-BHC, p, p-DDT, dieldrin, DDE, lindane, heptachlor and heptachlor epoxide were eluted from the snails. The highest levels of the pesticides were mostly detected out in the snails collected from the Donghae-Chun area of Haman and the Kangwha area of Kyongki-Do, where the lowest infection rates of trematode cercariae (0~0.5%) were revealed. The possibilities that the residual pesticides in the freshwater animals including Semisulcospira snails might be transferable to humans were also discussed.

• Journal of agricultural medicine and community health
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• v.10 no.1
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• pp.36-41
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• 1985

To evaluate the parasitic infection rates among inhabitants in urban area of Seoul, Korea, a total of 5,275 stool and anal swab specimens was obtained from 2,527 male and Z,748 female living in 24 Dongs of 17 Kus. Cases were sampled randomely to represent 1,000 inhabitants refereed to the census in 1980. The methods employed were formalin ether technique to detect helminth ova and protozoan cysts and scotch tape anal swab technique to detect eggs of Enterobius vermicularis. The results obtained are as follows ; 1) Total positive rate of helminthes was 23.5% among 5,275 (male 22.5% and female 24.5%) specimens. Nine kinds of the helminthes were detected and infection rates of each helminth were; Ascaris lumbricoides 4.1%, Hookworm 0.1%, Trichuris trichiura 11.1%, Trichostrongylus orientalis 0.1%. Clonorchis sinensis 1.2%, Metagonimus yokogawai 0.1%, Taenia spp. 0.2%, Hymenolepis nana 0.3 and Enterobius vermicularis 9.6%. 2) Total positive rate of intestinal protozoa was 1.4%. Four kinds of the protozoan cysts were detected and the infection rates of each protozoa were; Entamoeba histolytica 0.15%, E. coli 0.4%, Endolimax nana 0.04% and Giardia lamblia 0.89%. 3) No significant differences in the parasitic infection rate by sex was noticed although male group showed lower infection rate than female group. However the incidence of C. sinensis, M. yokogawai and Taenia spp. was twice as much in female group as in male group. 4) No difference in the infection rate by age was found although E. vermicularis positive rate was highest in "0~9 years group" by 2.1% and C. sinensis infection rate was higher in over "30~39 years group". The parasitic infection rate of the present study was significantly lower than those of previous reports in Seoul area and other provinces.

• Parasites, Hosts and Diseases
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• v.31 no.1
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• pp.43-48
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• 1993

Antibody test is sometimes necessary for the diagnosis of acute human metagonimiasis because eggs may not be detected in stool. The antibody test (ELISA) was evaluated for its significance by reacting human sera from clinically diagnosed metagonimiasis, fascioliasis, clonorchiasis and paragonimlasis with 4 crude extracts of Metosonimn vokognwai (metacercariael , adults of Fosciola hepatica Cronorchis sinenis and Paragonimus westermoni. By ELISA, 10 of 11 metagonimlasis sera showed the highest absorbance (abs.) to the homologous antigen. Cross reactions to M. yokogawai antigen occurred most frequently in clonorchiasis sera. The antigenic protein fractions in M. vokogawai metacercarial extract were observed by SDS-PAGElimmunoblot using patients and control sera together with experimental cat sera. Out of 14 protein bands In the extract, 11 bands were reacting. Cross reacting bands to other trematodiasis sera were frequently observed. Of the reacting bands, 66 and 22 kDa proteuls were recognized as specific for metagonimiasis.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.9-20
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• 1991

The present study intended to evaluate the influences of MetagonimMi yokogawai on the activities of brush border membrane bound enzymes of the small intestine. Mice were infected with 500 metacercariae respectively, and the worm recovery, morphological changes and enzyme activities were observed chronologically. A part of them were followed after the treatment. Recovered worms decreased in number continuously after the infection, and they were less than 10% after 2 weeks and almost Bero after 28 weeks. Villous atrophy and stromal inflammation were found at two locations of the proximal jejunum from 2 weeks to 4 weeks after the infection. The enzymes, alkaline phosphatase, leucine aminopeptidase and disaccharidases (sucrase, lactase, maltase, and trehalase), showed lowered activities in the duodenum and proximal jejunum of the infected mice but they increased in the distal jejunum for the first two weeks. From three weeks after the infection, the activities were gradually recovered. In one week treated mice, they recovered the activities at 2 weeks from the treatment, but there found no differences of the activities between the 3 week treated group and infected controls. The present data reveal that M. yckogawai infection induces degenerative changes of the host's intestinal mucosa not only morphologically but functionally during the initial phase of infection. The lowered enzyme activities in acute metagonimiasis should be associated with malabsorption and diarrhea.