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Jong-yil Chai - One of the best experts on this subject based on the ideXlab platform.

  • Survey on Intestinal Helminthic Infection Status of Students in Two Counties, Hadong-gun and Goseong-gun, Korea.
    The Korean Journal of Parasitology, 2018
    Co-Authors: Young Yil Bahk, Woon-mok Sohn, Jong-yil Chai, Yun-kyu Park, Sungjong Hong, Tongsoo Kim
    Abstract:

    This study was conducted to investigate the prevalence of intestinal parasites among students from Goseonggun, Gangwon-do and Hadong-gun, Gyeongsangnam-do as typical low and high endemic counties. From May to July 2017, a total of 2,033 fecal samples were collected at 27 elementary, 10 junior high, and 8 high schools from 2 counties and examined by the Kato-Katz technique for egg-positive surveys (Collection rate: 37.02% [2,033/5,492]). Of the participants examined, 13 (0.64%) were found to harbor eggs of 3 parasitic species, Trichuris trichiura, Clonorchis sinensis and Metagonimus Yokogawai. Based on the regional distribution, the egg-positive rate in Goseong-gun was 0% (0/550) and that in Hadong-gun was 0.88% (13/1,483). The positive rates for C. sinensis, M. Yokogawai, and T. trichiura in Hadonggun were 0.20% (3/1,483), 0.61% (9/1,483), and 0.07% (1/1,483), respectively. The present survey showed that the prevalence of parasitic infection among students is currently very low even in remote, previously endemic areas, and the present status of parasitic diseases can be summarized as some transmission of fish/food-borne trematodes. Thus, it is necessary to carefully, continuously monitor the trematode infection status, particularly of C. sinensis and M. Yokogawai.

  • Representative reaction curves of the multiplex real-time PCR assay.
    2016
    Co-Authors: Eun Jeong Won, Jong-yil Chai, Soo Hyun Kim, Seung Jung Kee, Jong Hee Shin, Soon Pal Suh, Dong Wook Ryang, Myung Geun Shin
    Abstract:

    A) Multiple reaction curves indicate amplification of the positive controls and clinical samples obtained from patients with gastroenteritis. B) Positive curves of two positive controls for Cryptosporidium parvum (tube 1) and Metagonimus Yokogawai (tube 2) were observed in the Quasar 670 channel. Patient No. 106’s sample showed a positive curve within tube 1 according to Quasar 670 signals. C) Positive curves of two positive controls for Blastocystis hominis (tube 1), Entamoeba histolytica (tube 2), and Dientamoeba fragilis (tube 3) were observed in the VIC/HEX channel. Patient No. 112’s sample showed a positive curve within tube 1 according to the VIC/HEX signals. D) Positive curves of two positive controls for Gymnophalloides seoi (tube 1), Giardia lamblia (tube 2), and Clonorchis sinensis (tube 3) were observed in the FAM channel. Patient No. 35’s sample showed a positive curve within tube 3 according to FAM signals.

  • Epidemiology of trematode infections.
    Advances in Experimental Medicine and Biology, 2014
    Co-Authors: Jong-yil Chai
    Abstract:

    Human-infecting digenetic trematodes are approximately 70 species which belong to 60 genera over the world. According to their habitat in the definitive hosts, they are classified as blood flukes (Schistosoma japonicum. S. mekongi, S. mansoni, S. haematobium, and S. intercalatum), liver flukes (Clonorchis sinensis, Opisthorchis viverrini, O. felineus, Metorchis conjunctus, Dicrocoelium dendriticum, Fasciola hepatica, and F. gigantica), lung flukes (Paragonimus westermani, P. heterotremus, P. skrjabini, P. skrjabini miyazakii, P. kellicotti, P. mexicanus, P. africanus, and P. uterobilateralis), and intestinal flukes (Metagonimus Yokogawai, M. miyatai, M. takahashii, Heterophyes nocens, H. heterophyes, Haplorchis taichui, H. pumilio, H. Yokogawai, Centrocestus formosanus, Echinostoma revolutum, E. ilocanum, E. hortense, Echinochasmus japonicus, E. lilliputanus, Artyfechinostomum malayanum, A. oraoni, Clinostomum complanatum, Eurytrema pancreaticum, Fasciolopsis buski, Gymnophalloides seoi, Neodiplostomum seoulense, Prosthodendrium molenkampi, Phaneropsolus bonnei, and Plagiorchis muris). The mode of transmission to humans include contact with cercariae contaminated in water (schistosomes) or ingestion of raw or improperly cooked fish (liver flukes, heterophyids, and echinostomes), snails (echinostomes and gymnophallids), amphibians, and reptiles (neodiplostomes). Praziquantel has been proved to be highly effective against most species of trematode infections except fascioliasis. Epidemiological surveys and detection of human infections are required for better understanding of the geographical distribution and endemicity of each trematode species.

  • Metagonimus Yokogawai: a 100-kDa somatic antigen commonly reacting with other trematodes.
    The Korean Journal of Parasitology, 2014
    Co-Authors: Eun-taek Han, Hyun-jong Yang, Young-jin Park, Jeong Hyun Park, Jong-yil Chai
    Abstract:

    This study was undertaken to characterize the properties of a 100 kDa somatic antigen from Metagonimus Yokogawai. Monoclonal antibodies (mAbs) were produced against this 100 kDa antigen, and their immunoreactivity was assessed by western blot analysis with patients' sera. The mAbs against the 100 kDa antigen commonly reacted with various kinds of trematode antigens, including intestinal (Gymnophalloides seoi), lung (Paragonimus westermani), and liver flukes (Clonorchis sinensis and Fasciola hepatica). However, this mAb showed no cross-reactions with other helminth parasites, including nematodes and cestodes. To determine the topographic distribution of the 100 kDa antigen in worm sections, indirect immunoperoxidase staining was performed. A strong positive reaction was observed in the tegumental and subtegumental layers of adult M. Yokogawai and C. sinensis. The results showed that the 100 kDa somatic protein of M. Yokogawai is a common antigen which recognizes a target epitope present over the tegumental layer of different trematode species.

  • The Changing Pattern of Parasitic Infection Among Korean Populations by Paleoparasitological Study of Joseon Dynasty Mummies
    Journal of Parasitology, 2014
    Co-Authors: Min Seo, Jong-yil Chai, Mi Sook Jeong, Sung Woo Hong, Young Min Seo, Dong Hoon Shin
    Abstract:

    In the coprolites of 4 recently discovered Joseon mummies of Korea, we found Ascaris lumbricoides, Trichuris trichiura, Metagonimus Yokogawai, Paragonimus westermani, and Clonorchis sinensis eggs. The current finding was compared with previous paleoparasitological data, and with recent national survey data from Korea. For A. lumbricoides and T. trichiura, similar patterns of infection prevalence were observed between the national survey of 1961 and our current Joseon data. Some of the trematode species (C. sinenesis and P. westermani) showed much higher infection prevalences among the Joseon Koreans than among their 1960s descendants. The present results indicate that the decrease in trematode infection rates might have begun earlier than was the case for nematode infection.

Soon-hyung Lee - One of the best experts on this subject based on the ideXlab platform.

  • A Nationwide Survey on the Prevalence of Intestinal Parasitic Infections in the Republic of Korea, 2004
    The Korean Journal of Parasitology, 2009
    Co-Authors: Tongsoo Kim, Woon-mok Sohn, Jong-yil Chai, Shinhyeong Cho, Yoon Kong, Soon-hyung Lee, Sun Huh, Seung Sik Hwang, Yun-kyu Park
    Abstract:

    National surveys on the prevalence of intestinal parasitic infections have been carried out every 5-7 years since 1971 in the Republic of Korea in order to establish control measures. The present nationwide survey was conducted from June to December 2004. The 10% population sampling data of Population and Housing Census by the Korean government in 2000 was used as the survey population. One sample was selected randomly from each of the 22,858 registered subjects, and a total of 20,541 people were ultimately included in this survey. Fecal examinations were performed by the cellophane thick smear and saturated brine flotation techniques. Pinworm infection was examined by cello-tape anal swab method. This survey also included a questionnaire study for a socioeconomic analysis. The total helminth egg positive rate was 3.7%, and the estimated total positive number among nationwide people was 1,780,000. The rates in urban and rural areas were 3.1% and 6.8%, respectively. As the total egg positive rate in the 6th survey in 1997 was 2.4%, the present survey showed that there was a considerable degree of increase in the prevalence rate of intestinal parasitic infections over the 7-year period following the 6th survey. The largest increases occurred in the egg positive rates of Clonorchis sinensis and heterophyids including Metagonimus Yokogawai.

  • high endemicity of Metagonimus Yokogawai infection among residents of samchok shi kangwon do
    Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p<0.05) for the males (46.6%) than the females (16.3%). From 11 cooperative cases in collection of adult flukes, a total of 242,119 adult specimens (average 22,010 per person, 367-119,650 in range) were collected (Table 2). All the flukes was identified as M. Yokogawai. Most of the infected people, especially those with more than 10,000 worms, recalled that they had experienced mild to severe degrees of gastrointestinal troubles including episodes of diarrhea and colicky pain. Many of the infected people admitted that they had eaten raw freshwater fish (Plecoglossus altivelis) caught around this area. Fig. 1 Metagonimus Yokogawai egg positive rates by age and sex of residents in Samchok-shi, Kangwon-do. Table 2 Number of M. Yokogawai specimens collected from egg positive cases after praziquantel treatment and purgation In Korea, three species of Metagonimus are known to occur; M. Yokogawai (Chai and Lee, 1990), M. miyatai (Chai et al., 1993; Saito et al., 1997), and M. takahashii (Ahn and Ryang, 1988; Chai et al., 1993). However, the majority of epidemiological studies have been conducted on M. Yokogawai (Seo et al., 1981; Song et al., 1985; Chai and Lee, 1990). Large and small rivers in the eastern and southern coastal areas, where sweetfish are available, have turned out to be endemic foci of M. Yokogawai infection (Chai and Lee, 1990; Chai et al., 1998). According to a survey along the five major rivers, the average egg positive rate of riverside people was 4.8% (Seo et al., 1981). Other studies have revealed that the Somjingang (River), Tamjingang (River), Bosonggang (River), and Kojedo (Island) were found to be highly endemic with 10-40% egg positive rates among the residents (Yeo and Seo, 1971; Soh et al., 1976; Chai et al., 1977; Seo et al., 1981). In general population, however, quinquennial national surveys showed 1.2% egg positive rate in 1981, 1.0% in 1986, and 0.3% in 1992 and 1997 (Ministry of Health and Welfare and Korea Association of Health, 1997). Around this area, two epidemiological surveys were performed on M. Yokogawai infection previously (Seo et al., 1981; Ahn, 1984). According to the former report (Seo et al., 1981), the egg positive rate was 28.5%, a figure very similar to the present study. Compared to the latter (Ahn, 1984) in which the rate was reported as 35.4%, only a little decrease was recognized in the present study. This persistent endemicity of M. Yokogawai in this area is undoubtedly related to a continued raw eating habbit of sweetfish by the local residents, especially among the adult age group. It is noteworthy, however, to mention that no school children were found to be infected, which could be a result from a successful health education among this age group. In other areas of the eastern coasts, variable infection rates of residents were reported previously; 9.4% in Ulchu-gun (Joo and Park, 1982), 23.1% in Ulchin-shi, and 6.7% in Miryang-gun (Seo et al., 1981), all of which showed lower prevalences than in the present study. As far as the intensity of infection in terms of the number of worms in each person is concerned, there have been a few reports in Korea. A report of two cases who expelled 17,560 and 154 worms after a treatment was the first which documented the intensity of infection (Seo et al., 1971). Near the basin of Tamjin River, where the egg positive rate of M. Yokogawai was 40.3%, the intensity of infection in average EPG (eggs per gram of feces) was 1,707 (Chai et al., 1977). It seems worthwhile to note that 2,886-63,587 adult flukes were collected individually from 14 infected people in Tamjin River basin (Seo et al., 1985), which became the most recent record on the worm burden of M. Yokogawai. Therefore, the worm burdens of 119,650 (patient No. 1) and 68,170 (patient No. 2) in this study are the heaviest record among the literature. The infected people experienced mild to severe degrees of gastrointestinal troubles including diarrhea, and the two heaviest cases recalled that they had repeated episodes of profuse diarrhea and colicky pain. Taken together, the results of the present study suggest that M. Yokogawai is still highly endemic along the Osib-chon (Stream), Samchok-shi. Proper control measures are urgently needed in this area.

  • High endemicity of Metagonimus Yokogawai infection among residents of Samchok-shi, Kangwon-do.
    The Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p

  • Effects of gamma-irradiation on the survival and development of Metagonimus Yokogawai metacercariae in rats.
    The Korean Journal of Parasitology, 1995
    Co-Authors: Jong-yil Chai, Sang-joon Kim, Jina Kook, Soon-hyung Lee
    Abstract:

    To evaluate the feasibility of irradiation as a control measure for metagonimiasis, the metacercariae of Metagonimus Yokogawai were irradiated with gamma ray, either after isolation from the sweetfish (Plecoglossus altivelis) or in situ of the fish, and their survival and development in rats were observed at 7 days post-infection. The radiation dose varied from 5 to 100 Gy for the metacercaria-irradiation group and from 5 to 500 Gy for fish-irradiation group. The results showed that the worm recovery rate from the irradiation groups decreased as the radiation dose was increased. Higher doses of radiation were required for the fish-irradiation group to obtain the same results as the metacercaria-irradiation group. The LD50 of the metacercaria-irradiation group was 4.5 Gy, whereas that of the fish-irradiation group 6.2 Gy. A few number of worms which survived until 7 days in rats were severely retarded especially in the growth of their reproductive organs, i.e., complete or partial failure in the development of testes and formation of uterine eggs. The present study revealed that irradiation of sweetfish by 200 Gy is effective to control infectivity as well as development of M. Yokogawai metacercaria in rats.

  • Invasion of Metagonimus Yokogawai into the submucosal layer of the small intestine of immunosuppressed mice
    The Korean Journal of Parasitology, 1995
    Co-Authors: Jong-yil Chai, Jin Kim, Soon-hyung Lee
    Abstract:

    Metosonimus yokosawai was found deeply invaded into the submucosa of the small intestine of mice (ICR) when they were immunosuppressed by prednisolone injection. Experimental groups consisted of control, fluke infection (1,800 metacercariae per mouse) and fluke infection plus immunosuppression. In fluke infection group, many worms were found sectioned in the intervillous space of the jejunum and ileum at 6 hrs, 12 hrs, and 1 day after infection, and pathological changes characterized by villous atrophy and crypt hyperplasia were observed. After 3 days, only a few worms were found in intestinal sections, and after 7 days, the pathological changes became minimal. No worm was found penetrated beyond the mucosal layer. On the other hand, in immunosuppressed mice, numerous worms were found sectioned in the duodenum and jejunum, irrespective of the infection period up to 14 days. Pathological changes of the mucosa were minimal until 3 days after infection, but at 5 days marked destruction of the mucosal layer was observed. At this time many flukes were found invaded deeply into the submucosa facing the muscular layer. Despite continuous immunosuppression, the mucosal damage was gradually recovered at 7-21 days post-infection. The results showed that immunosuppression of ICR mice can induce, for a short perid of time, severe mucosal damage, and allow deep invasion of M. yokogcuwai into the submucosa of the small intestine. Key words: Metngonimus Wokosaulai, prednisolone, immunosuppression, intestinal pathology, worm invasion

Jae-lip Kim - One of the best experts on this subject based on the ideXlab platform.

  • Decrease of Metagonimus Yokogawai endemicity along the Tamjin River basin.
    The Korean Journal of Parasitology, 2008
    Co-Authors: Jin-ju Lee, Hyo-jin Kim, Min Jae Kim, Jo Woon Yi Lee, Bong-kwang Jung, Jiyoun Lee, Eun-hee Shin, Jae-lip Kim, Jong-yil Chai
    Abstract:

    The Tamjin River which flows from Jangheung-gun via Gangjin-gun to the South Sea was reported to be a highly endemic area of Metagonimus Yokogawai infection in 1977 and 1985. However, there were no recent studies demonstrating how much change occurred in the endemicity, in terms of prevalence and worm burden, of metagonimiasis in this river basin. Thus, a small-scale epidemiological survey was carried out on some residents along the Tamjin River basin in order to determine the current status of M. Yokogawai infection. A total of 48 fecal samples were collected and examined by the Kato-Katz thick smear and formalin-ether sedimentation techniques. The egg positive rate of all helminths was 50.0%, and that of M. Yokogawai was 37.5%, followed by C. sinensis 22.9% and G. seoi 4.2%. To obtain the adult flukes of M. Yokogawai, 6 egg positive cases were treated with praziquantel 10 mg/kg in a single dose and purged with magnesium sulfate. A total of 5,225 adult flukes (average 871 specimens per person) of M. Yokogawai were collected from their diarrheic stools. Compared with the data reported in 1977 and 1985, the individual worm burdens appeared to have decreased remarkably, although the prevalence did not decrease at all. It is suggested that the endemicity of M. Yokogawai infection along the Tamjin River has been reduced. To confirm this suggestion, the status of infection in snail and fish intermediate hosts should be investigated.

  • SUSCEPTIBILITY OF INBRED MOUSE STRAINS TO INFECTION WITH THREE SPECIES OF Metagonimus PREVALENT IN THE REPUBLIC OF KOREA
    Journal of Parasitology, 2005
    Co-Authors: Sang-mee Guk, Eun-taek Han, Jae-lip Kim, Min Seo, Jin Young Park, Jong-yil Chai
    Abstract:

    Susceptibility of inbred mouse strains to Metagonimus Yokogawai, Metagonimus miyatai, and Metagonimus takahashii infections was studied using BALB/c, ddY, C57BL/6J, C3H/HeN, and A/J mice, with H-2 haplotypes d, s, b, k, and a, respectively. Two hundred metacercariae were orally fed to each mouse, and the worm recovery rates (WRR), worm dimensions, and intrauterine egg numbers were measured at days 3, 7, 14, 21, and 28 postinfection (PI). On day 14 PI, the WRR of M. Yokogawai was highest in ddY mice (average, 62.2%); those of M. miyatai and M. takahashii were highest in ddY (19.5%) and BALB/c mice (10.4%), respectively; worm maturation was best in C3H/HeN (M. Yokogawai), C57BL/6J (M. miyatai), and ddY mice (M. takahashii). All mouse strains showed higher susceptibility to infection with M. Yokogawai than with M. miyatai or M. takahashii. The results show that susceptibility of mice to Metagonimus infection varies according to mouse strain and parasite species but is suggested to be independent of the mouse H-2 haplotype.

  • high endemicity of Metagonimus Yokogawai infection among residents of samchok shi kangwon do
    Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p<0.05) for the males (46.6%) than the females (16.3%). From 11 cooperative cases in collection of adult flukes, a total of 242,119 adult specimens (average 22,010 per person, 367-119,650 in range) were collected (Table 2). All the flukes was identified as M. Yokogawai. Most of the infected people, especially those with more than 10,000 worms, recalled that they had experienced mild to severe degrees of gastrointestinal troubles including episodes of diarrhea and colicky pain. Many of the infected people admitted that they had eaten raw freshwater fish (Plecoglossus altivelis) caught around this area. Fig. 1 Metagonimus Yokogawai egg positive rates by age and sex of residents in Samchok-shi, Kangwon-do. Table 2 Number of M. Yokogawai specimens collected from egg positive cases after praziquantel treatment and purgation In Korea, three species of Metagonimus are known to occur; M. Yokogawai (Chai and Lee, 1990), M. miyatai (Chai et al., 1993; Saito et al., 1997), and M. takahashii (Ahn and Ryang, 1988; Chai et al., 1993). However, the majority of epidemiological studies have been conducted on M. Yokogawai (Seo et al., 1981; Song et al., 1985; Chai and Lee, 1990). Large and small rivers in the eastern and southern coastal areas, where sweetfish are available, have turned out to be endemic foci of M. Yokogawai infection (Chai and Lee, 1990; Chai et al., 1998). According to a survey along the five major rivers, the average egg positive rate of riverside people was 4.8% (Seo et al., 1981). Other studies have revealed that the Somjingang (River), Tamjingang (River), Bosonggang (River), and Kojedo (Island) were found to be highly endemic with 10-40% egg positive rates among the residents (Yeo and Seo, 1971; Soh et al., 1976; Chai et al., 1977; Seo et al., 1981). In general population, however, quinquennial national surveys showed 1.2% egg positive rate in 1981, 1.0% in 1986, and 0.3% in 1992 and 1997 (Ministry of Health and Welfare and Korea Association of Health, 1997). Around this area, two epidemiological surveys were performed on M. Yokogawai infection previously (Seo et al., 1981; Ahn, 1984). According to the former report (Seo et al., 1981), the egg positive rate was 28.5%, a figure very similar to the present study. Compared to the latter (Ahn, 1984) in which the rate was reported as 35.4%, only a little decrease was recognized in the present study. This persistent endemicity of M. Yokogawai in this area is undoubtedly related to a continued raw eating habbit of sweetfish by the local residents, especially among the adult age group. It is noteworthy, however, to mention that no school children were found to be infected, which could be a result from a successful health education among this age group. In other areas of the eastern coasts, variable infection rates of residents were reported previously; 9.4% in Ulchu-gun (Joo and Park, 1982), 23.1% in Ulchin-shi, and 6.7% in Miryang-gun (Seo et al., 1981), all of which showed lower prevalences than in the present study. As far as the intensity of infection in terms of the number of worms in each person is concerned, there have been a few reports in Korea. A report of two cases who expelled 17,560 and 154 worms after a treatment was the first which documented the intensity of infection (Seo et al., 1971). Near the basin of Tamjin River, where the egg positive rate of M. Yokogawai was 40.3%, the intensity of infection in average EPG (eggs per gram of feces) was 1,707 (Chai et al., 1977). It seems worthwhile to note that 2,886-63,587 adult flukes were collected individually from 14 infected people in Tamjin River basin (Seo et al., 1985), which became the most recent record on the worm burden of M. Yokogawai. Therefore, the worm burdens of 119,650 (patient No. 1) and 68,170 (patient No. 2) in this study are the heaviest record among the literature. The infected people experienced mild to severe degrees of gastrointestinal troubles including diarrhea, and the two heaviest cases recalled that they had repeated episodes of profuse diarrhea and colicky pain. Taken together, the results of the present study suggest that M. Yokogawai is still highly endemic along the Osib-chon (Stream), Samchok-shi. Proper control measures are urgently needed in this area.

  • High endemicity of Metagonimus Yokogawai infection among residents of Samchok-shi, Kangwon-do.
    The Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p

Yun-kyu Park - One of the best experts on this subject based on the ideXlab platform.

  • Survey on Intestinal Helminthic Infection Status of Students in Two Counties, Hadong-gun and Goseong-gun, Korea.
    The Korean Journal of Parasitology, 2018
    Co-Authors: Young Yil Bahk, Woon-mok Sohn, Jong-yil Chai, Yun-kyu Park, Sungjong Hong, Tongsoo Kim
    Abstract:

    This study was conducted to investigate the prevalence of intestinal parasites among students from Goseonggun, Gangwon-do and Hadong-gun, Gyeongsangnam-do as typical low and high endemic counties. From May to July 2017, a total of 2,033 fecal samples were collected at 27 elementary, 10 junior high, and 8 high schools from 2 counties and examined by the Kato-Katz technique for egg-positive surveys (Collection rate: 37.02% [2,033/5,492]). Of the participants examined, 13 (0.64%) were found to harbor eggs of 3 parasitic species, Trichuris trichiura, Clonorchis sinensis and Metagonimus Yokogawai. Based on the regional distribution, the egg-positive rate in Goseong-gun was 0% (0/550) and that in Hadong-gun was 0.88% (13/1,483). The positive rates for C. sinensis, M. Yokogawai, and T. trichiura in Hadonggun were 0.20% (3/1,483), 0.61% (9/1,483), and 0.07% (1/1,483), respectively. The present survey showed that the prevalence of parasitic infection among students is currently very low even in remote, previously endemic areas, and the present status of parasitic diseases can be summarized as some transmission of fish/food-borne trematodes. Thus, it is necessary to carefully, continuously monitor the trematode infection status, particularly of C. sinensis and M. Yokogawai.

  • Discovery of Parasite Eggs in Archeological Residence during the 15th Century in Seoul, Korea
    The Korean Journal of Parasitology, 2017
    Co-Authors: Pyo Yeon Cho, Tongsoo Kim, Yun-kyu Park, Jung-min Park, Myeong Ki Hwang, Seo Hye Park, Bo-young Jeon, Hyeong Woo Lee
    Abstract:

    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 Ascaris lumbricoides (n=483), followed by Trichuris trichiura (138), Trichuris vulpis (21), Fasciola hepatica (8), Clonorchis sinensis (6), Paragonimus westermani (4), and Metagonimus Yokogawai (2). These findings indirectly indicate the food habits of the people in Yi dynasty.

  • Development of a polymerase chain reaction applicable to rapid and sensitive detection of Clonorchis sinensis eggs in human stool samples
    Pathogens and Global Health, 2013
    Co-Authors: Pyo Yun Cho, Shinhyeong Cho, Yun-kyu Park, Kyung Mi Choi, Jin Su Kim, Won-ja Lee, Sung-bin Lim, Seok Ho Cha, Jhang Ho Pak
    Abstract:

    Microscopic examination of eggs of parasitic helminths in stool samples has been the most widely used classical diagnostic method for infections, but tiny and low numbers of eggs in stool samples often hamper diagnosis of helminthic infections with classical microscopic examination. Moreover, it is also difficult to differentiate parasite eggs by the classical method, if they have similar morphological characteristics. In this study, we developed a rapid and sensitive polymerase chain reaction (PCR)-based molecular diagnostic method for detection of Clonorchis sinensis eggs in stool samples. Nine primers were designed based on the long-terminal repeat (LTR) of C. sinensis retrotransposon1 (CsRn1) gene, and seven PCR primer sets were paired. Polymerase chain reaction with each primer pair produced specific amplicons for C. sinensis, but not for other trematodes including Metagonimus Yokogawai and Paragonimus westermani. Particularly, three primer sets were able to detect 10 C. sinensis eggs and were applicable to amplify specific amplicons from DNA samples purified from stool of C. sinensis-infected patients. This PCR method could be useful for diagnosis of C. sinensis infections in human stool samples with a high level of specificity and sensitivity.

  • A Nationwide Survey on the Prevalence of Intestinal Parasitic Infections in the Republic of Korea, 2004
    The Korean Journal of Parasitology, 2009
    Co-Authors: Tongsoo Kim, Woon-mok Sohn, Jong-yil Chai, Shinhyeong Cho, Yoon Kong, Soon-hyung Lee, Sun Huh, Seung Sik Hwang, Yun-kyu Park
    Abstract:

    National surveys on the prevalence of intestinal parasitic infections have been carried out every 5-7 years since 1971 in the Republic of Korea in order to establish control measures. The present nationwide survey was conducted from June to December 2004. The 10% population sampling data of Population and Housing Census by the Korean government in 2000 was used as the survey population. One sample was selected randomly from each of the 22,858 registered subjects, and a total of 20,541 people were ultimately included in this survey. Fecal examinations were performed by the cellophane thick smear and saturated brine flotation techniques. Pinworm infection was examined by cello-tape anal swab method. This survey also included a questionnaire study for a socioeconomic analysis. The total helminth egg positive rate was 3.7%, and the estimated total positive number among nationwide people was 1,780,000. The rates in urban and rural areas were 3.1% and 6.8%, respectively. As the total egg positive rate in the 6th survey in 1997 was 2.4%, the present survey showed that there was a considerable degree of increase in the prevalence rate of intestinal parasitic infections over the 7-year period following the 6th survey. The largest increases occurred in the egg positive rates of Clonorchis sinensis and heterophyids including Metagonimus Yokogawai.

  • high endemicity of Metagonimus Yokogawai infection among residents of samchok shi kangwon do
    Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p<0.05) for the males (46.6%) than the females (16.3%). From 11 cooperative cases in collection of adult flukes, a total of 242,119 adult specimens (average 22,010 per person, 367-119,650 in range) were collected (Table 2). All the flukes was identified as M. Yokogawai. Most of the infected people, especially those with more than 10,000 worms, recalled that they had experienced mild to severe degrees of gastrointestinal troubles including episodes of diarrhea and colicky pain. Many of the infected people admitted that they had eaten raw freshwater fish (Plecoglossus altivelis) caught around this area. Fig. 1 Metagonimus Yokogawai egg positive rates by age and sex of residents in Samchok-shi, Kangwon-do. Table 2 Number of M. Yokogawai specimens collected from egg positive cases after praziquantel treatment and purgation In Korea, three species of Metagonimus are known to occur; M. Yokogawai (Chai and Lee, 1990), M. miyatai (Chai et al., 1993; Saito et al., 1997), and M. takahashii (Ahn and Ryang, 1988; Chai et al., 1993). However, the majority of epidemiological studies have been conducted on M. Yokogawai (Seo et al., 1981; Song et al., 1985; Chai and Lee, 1990). Large and small rivers in the eastern and southern coastal areas, where sweetfish are available, have turned out to be endemic foci of M. Yokogawai infection (Chai and Lee, 1990; Chai et al., 1998). According to a survey along the five major rivers, the average egg positive rate of riverside people was 4.8% (Seo et al., 1981). Other studies have revealed that the Somjingang (River), Tamjingang (River), Bosonggang (River), and Kojedo (Island) were found to be highly endemic with 10-40% egg positive rates among the residents (Yeo and Seo, 1971; Soh et al., 1976; Chai et al., 1977; Seo et al., 1981). In general population, however, quinquennial national surveys showed 1.2% egg positive rate in 1981, 1.0% in 1986, and 0.3% in 1992 and 1997 (Ministry of Health and Welfare and Korea Association of Health, 1997). Around this area, two epidemiological surveys were performed on M. Yokogawai infection previously (Seo et al., 1981; Ahn, 1984). According to the former report (Seo et al., 1981), the egg positive rate was 28.5%, a figure very similar to the present study. Compared to the latter (Ahn, 1984) in which the rate was reported as 35.4%, only a little decrease was recognized in the present study. This persistent endemicity of M. Yokogawai in this area is undoubtedly related to a continued raw eating habbit of sweetfish by the local residents, especially among the adult age group. It is noteworthy, however, to mention that no school children were found to be infected, which could be a result from a successful health education among this age group. In other areas of the eastern coasts, variable infection rates of residents were reported previously; 9.4% in Ulchu-gun (Joo and Park, 1982), 23.1% in Ulchin-shi, and 6.7% in Miryang-gun (Seo et al., 1981), all of which showed lower prevalences than in the present study. As far as the intensity of infection in terms of the number of worms in each person is concerned, there have been a few reports in Korea. A report of two cases who expelled 17,560 and 154 worms after a treatment was the first which documented the intensity of infection (Seo et al., 1971). Near the basin of Tamjin River, where the egg positive rate of M. Yokogawai was 40.3%, the intensity of infection in average EPG (eggs per gram of feces) was 1,707 (Chai et al., 1977). It seems worthwhile to note that 2,886-63,587 adult flukes were collected individually from 14 infected people in Tamjin River basin (Seo et al., 1985), which became the most recent record on the worm burden of M. Yokogawai. Therefore, the worm burdens of 119,650 (patient No. 1) and 68,170 (patient No. 2) in this study are the heaviest record among the literature. The infected people experienced mild to severe degrees of gastrointestinal troubles including diarrhea, and the two heaviest cases recalled that they had repeated episodes of profuse diarrhea and colicky pain. Taken together, the results of the present study suggest that M. Yokogawai is still highly endemic along the Osib-chon (Stream), Samchok-shi. Proper control measures are urgently needed in this area.

Sang-mee Guk - One of the best experts on this subject based on the ideXlab platform.

  • Gymnophalloides seoi Eggs from the Stool of a 17th Century Female Mummy Found in Hadong, Republic of Korea
    Journal of Parasitology, 2008
    Co-Authors: Min Seo, Sang-mee Guk, Dong Hoon Shin, Eun Joo Lee, Myung Ho Shin, Myeung Ju Kim, Soong Deok Lee, Yi-suk Kim
    Abstract:

    It was previously reported that paleoparasitological clues for parasites infecting humans could be found in the feces of mummies of the Joseon Dynasty (1392–1910) in the Republic of Korea. Here, we report the presence of trematode eggs, including Clonorchis sinensis, Metagonimus Yokogawai, and Gymnophalloides seoi (a human parasite known in Korea since 1993) in the feces of a recently excavated female mummy in Hadong, Republic of Korea. This is the first report of the discovery of a G. seoi infection in a human mummy. Since Hadong is currently not an endemic area for G. seoi, we speculate that the parasite might have occurred frequently along coastal areas of the Korean peninsula several hundred years ago and that the endemic areas contracted to, more or less, restricted regions since that time.

  • SUSCEPTIBILITY OF INBRED MOUSE STRAINS TO INFECTION WITH THREE SPECIES OF Metagonimus PREVALENT IN THE REPUBLIC OF KOREA
    Journal of Parasitology, 2005
    Co-Authors: Sang-mee Guk, Eun-taek Han, Jae-lip Kim, Min Seo, Jin Young Park, Jong-yil Chai
    Abstract:

    Susceptibility of inbred mouse strains to Metagonimus Yokogawai, Metagonimus miyatai, and Metagonimus takahashii infections was studied using BALB/c, ddY, C57BL/6J, C3H/HeN, and A/J mice, with H-2 haplotypes d, s, b, k, and a, respectively. Two hundred metacercariae were orally fed to each mouse, and the worm recovery rates (WRR), worm dimensions, and intrauterine egg numbers were measured at days 3, 7, 14, 21, and 28 postinfection (PI). On day 14 PI, the WRR of M. Yokogawai was highest in ddY mice (average, 62.2%); those of M. miyatai and M. takahashii were highest in ddY (19.5%) and BALB/c mice (10.4%), respectively; worm maturation was best in C3H/HeN (M. Yokogawai), C57BL/6J (M. miyatai), and ddY mice (M. takahashii). All mouse strains showed higher susceptibility to infection with M. Yokogawai than with M. miyatai or M. takahashii. The results show that susceptibility of mice to Metagonimus infection varies according to mouse strain and parasite species but is suggested to be independent of the mouse H-2 haplotype.

  • high endemicity of Metagonimus Yokogawai infection among residents of samchok shi kangwon do
    Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p<0.05) for the males (46.6%) than the females (16.3%). From 11 cooperative cases in collection of adult flukes, a total of 242,119 adult specimens (average 22,010 per person, 367-119,650 in range) were collected (Table 2). All the flukes was identified as M. Yokogawai. Most of the infected people, especially those with more than 10,000 worms, recalled that they had experienced mild to severe degrees of gastrointestinal troubles including episodes of diarrhea and colicky pain. Many of the infected people admitted that they had eaten raw freshwater fish (Plecoglossus altivelis) caught around this area. Fig. 1 Metagonimus Yokogawai egg positive rates by age and sex of residents in Samchok-shi, Kangwon-do. Table 2 Number of M. Yokogawai specimens collected from egg positive cases after praziquantel treatment and purgation In Korea, three species of Metagonimus are known to occur; M. Yokogawai (Chai and Lee, 1990), M. miyatai (Chai et al., 1993; Saito et al., 1997), and M. takahashii (Ahn and Ryang, 1988; Chai et al., 1993). However, the majority of epidemiological studies have been conducted on M. Yokogawai (Seo et al., 1981; Song et al., 1985; Chai and Lee, 1990). Large and small rivers in the eastern and southern coastal areas, where sweetfish are available, have turned out to be endemic foci of M. Yokogawai infection (Chai and Lee, 1990; Chai et al., 1998). According to a survey along the five major rivers, the average egg positive rate of riverside people was 4.8% (Seo et al., 1981). Other studies have revealed that the Somjingang (River), Tamjingang (River), Bosonggang (River), and Kojedo (Island) were found to be highly endemic with 10-40% egg positive rates among the residents (Yeo and Seo, 1971; Soh et al., 1976; Chai et al., 1977; Seo et al., 1981). In general population, however, quinquennial national surveys showed 1.2% egg positive rate in 1981, 1.0% in 1986, and 0.3% in 1992 and 1997 (Ministry of Health and Welfare and Korea Association of Health, 1997). Around this area, two epidemiological surveys were performed on M. Yokogawai infection previously (Seo et al., 1981; Ahn, 1984). According to the former report (Seo et al., 1981), the egg positive rate was 28.5%, a figure very similar to the present study. Compared to the latter (Ahn, 1984) in which the rate was reported as 35.4%, only a little decrease was recognized in the present study. This persistent endemicity of M. Yokogawai in this area is undoubtedly related to a continued raw eating habbit of sweetfish by the local residents, especially among the adult age group. It is noteworthy, however, to mention that no school children were found to be infected, which could be a result from a successful health education among this age group. In other areas of the eastern coasts, variable infection rates of residents were reported previously; 9.4% in Ulchu-gun (Joo and Park, 1982), 23.1% in Ulchin-shi, and 6.7% in Miryang-gun (Seo et al., 1981), all of which showed lower prevalences than in the present study. As far as the intensity of infection in terms of the number of worms in each person is concerned, there have been a few reports in Korea. A report of two cases who expelled 17,560 and 154 worms after a treatment was the first which documented the intensity of infection (Seo et al., 1971). Near the basin of Tamjin River, where the egg positive rate of M. Yokogawai was 40.3%, the intensity of infection in average EPG (eggs per gram of feces) was 1,707 (Chai et al., 1977). It seems worthwhile to note that 2,886-63,587 adult flukes were collected individually from 14 infected people in Tamjin River basin (Seo et al., 1985), which became the most recent record on the worm burden of M. Yokogawai. Therefore, the worm burdens of 119,650 (patient No. 1) and 68,170 (patient No. 2) in this study are the heaviest record among the literature. The infected people experienced mild to severe degrees of gastrointestinal troubles including diarrhea, and the two heaviest cases recalled that they had repeated episodes of profuse diarrhea and colicky pain. Taken together, the results of the present study suggest that M. Yokogawai is still highly endemic along the Osib-chon (Stream), Samchok-shi. Proper control measures are urgently needed in this area.

  • High endemicity of Metagonimus Yokogawai infection among residents of Samchok-shi, Kangwon-do.
    The Korean Journal of Parasitology, 2000
    Co-Authors: Jong-yil Chai, Eun-taek Han, Jae-lip Kim, Yun-kyu Park, Sang-mee Guk, Soon-hyung Lee
    Abstract:

    Of many species of heterophyid flukes known to occur in Korea, Metagonimus Yokogawai is the most important one with respect to general public health (Chai and Lee, 1990). In heavily infected patients the infection can cause severe gastrointestinal troubles and easy fatiguability. Metagonimus Yokogawai is widely distributed along the riverside areas of the southern and eastern coasts where sweetfish are available (Seo et al., 1982; Chai and Lee, 1990). In areas near Samchok-shi, Kangwon-do, a few epidemiological studies have been performed (Seo et al., 1981; Ahn, 1984; Song et al., 1985). However, worm collection studies that determine the intensity of infection have never been carried out along the eastern coasts including Samchok-shi. The present study was, therefore, aimed to investigate the prevalence and the intensity of M. Yokogawai infection among the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province). Fecal specimens were collected from 165 people, including both sexes and all age groups, residing in two small villages (Sanggoro-ri and Hagoro-ri) in Miro-myon, Samchok-shi, during the period from November 1997 through January 1998. They were examined by both cellophane thick smear and formalin-ether sedimentation techniques. After the fecal examination, some of the cases showing a high number of eggs were treated with 10 mg/kg single dose of praziquantel, followed by purgation with 30-40 g of MgSO4. Among the treated cases, 11 were cooperative in collection of diarrheic stools more than five consecutive times during 3-4 hr directly after the treatment. Diarrheic stools were washed several times with tap water, and the sediment was fixed with 1% formalin and transported to our laboratory. The flukes were collected under a stereomicroscope and the number was counted. Some of the specimens were flattened gently under a cover slip pressure, which were fixed with 10% neutral buffered formalin and stained with Semichon's acetocarmine. Through the fecal examination, various kinds of helminth eggs and protozoan cysts were detected (Table 1). Overall egg and/or cyst positive rate was 32.7% (54 out of 165 examined). The egg positive rate of helminths was the highest for M. Yokogawai (29.7%) followed by Trichuris trichiura (0.6%), Enterobius vermicularis (0.6%), and Clonorchis sinensis (0.6%). The cyst positive rate was relatively low; Entamoeba coli (1.6%) and Giardia lamblia (1.2%). Table 1 Results of fecal examination of the residents in Samchok-shi, Kangwon-do (1997-1998)a) In the case of M. Yokogawai infection, the highest egg positive rate was observed in the age group of 61-70 years (40.7%), followed by the forties (38.9%) and the fifties (33.3%) (Fig. 1). Among the younger age groups, less than 20 years, no infected cases were detected. The positive rate was significantly higher (p