• Parasites, Hosts and Diseases
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• 제51권6호
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• pp.703-710
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• 2013

To increase public health awareness for prevention of opisthorchiasis caused by eating raw freshwater fish, the distribution and abundance of Opisthorchis viverrini metacercariae (OV MC) was investigated in freshwater fish obtained from 20 provinces in northeastern Thailand between April 2011 and February 2012. A cross-sectional survey was conducted on 12,890 fish consisting of 13 species randomly caught from 26 rivers, 10 dams, and 38 ponds/lakes. Fish, were collected in each of the rainy and winter seasons from each province. Fish were identified, counted, weighed, and digested using pepsin-HCl. Samples were examined for OV MC by a sedimentation method, and metacercariae were identified under a stereomicroscope. OV MC were found in 6 species of fish; i.e., Cyclocheilichthys armatus, Puntius orphoides, Hampala dispar, Henicorhynchus siamensis, Osteochilus hasselti, and Puntioplites proctozysron from localities in 13 provinces. Among the sites where OV MC-infected fish were found, 70.0% were dams, 23.7% were ponds/lakes, and 7.7% were rivers. The mean intensity of OV MC ranged from 0.01 to 6.5 cysts per fish (or 1.3-287.5 cysts per kg of fish). A high mean intensity of OV MC per fish (>3 cysts) was found in 5 provinces: Amnat Charoen (6.5 cysts), Nakhon Phanom (4.3), Mukdahan (4.1), Khon Kaen, (3.5) and Si Sa Ket (3.4). In conclusion, OV MC are prevalent in natural cyprinid fish, with the infection rate varying according to fish species and habitats.

• Parasites, Hosts and Diseases
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• 제23권1호
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• pp.95-101
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• 1985

Fascioliasis in cattle is one of the most common and very serious trematode diseases in Korea. In the present study, the enzyme linked immunosorbent assay (ELISA) was applied in the diagnosis of fascioliasis using antigen of Fasciela hepatica, perokidase of conjugate anti-cattle Is G and orthophenylenediamine as a substrate by micro-method technique of Volley et at. (1976b) and MacLaren (1978) with a slight modification. Results obtained from the present study are as follows. 1. In assay for optimal dilution of stock antigen, the antigen (protein contents; 0. Bmgymz) was diluted from 1150 to 1/600 with carbonate buffer (pH 9.6), and then absorbance values were measured with 1/100 diluted sera. The regression equations between the OD values of ELISA and dilution of antigen were log Y: -0.181-0.00127X in infected sera, and log Y: -0.578-0. 000879X in normal sera. The significantly higher (p<0.05) OD value was observed in the former. 2. In assay for optimal dilution of sera, the sera were diluted from 1125 to 1/400 with in PBSJ Tween 20 (pH 7.4), and absorbance values were measured with 1/200 diluted antigen. The regression equation between the OD values of ELISA and dilution of sera were log Y: -0.1540-0.0007238X in infected sera and log Y: -0.4834-0.00116X in normal sera. The former was higher than the latter (p<0.05). 3. In the 27 cases of negative intradermal test, OD values of the ELISA are $0.447{\pm}0.144$, the 95% confidence interval (Mean+2 H SD) of the values was 0.735, and there was no case over the values. Therefore, the sensitivity of the antigen to diagnose fascioliasis was 100% in the negative case. The OD value 0.7 which is designed as a criterion (detection level of positive one) is useful for the performance of the ELISA in fascioliasis. 4. According to the OD value of criterion in the regression equations, the optimal dilutions of stock antigen and serum were 1/250 and 1/100, respectively. 5. In the 58 cases of fascioliasis from which the adult could be found in the bile ducts, the OD value was $0.846{\pm}0.224$. The 75% (44 cattle) among them had higher value with compared to the criterion, and the 60% (20 cattle) of the cases of proliferative cholangitis of 33 cattle which had been infected previousely with Fasciola sp. is higher than the criterion. 6. Prevalence of fascioliasis was 43.4% in the application of the ELISA to 272 cattle which were reared in Jeonbug district.

• Parasites, Hosts and Diseases
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• 제28권4호
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• pp.235-240
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• 1990

1989년 8∼9월에 강원도 양양군 현북면에서 잡은 집쥐 2마리에서 Echinostoma hortense, E. cinetorchis, E. revolutum, Echinoparyphium recurvatum, Fibricola seoulensis 및 Plagiorchis tsuris 등 모두 6종류의 장흡충을 검출하였다. 이들 중 E. revolutum과 E. recurvatum은 국내산 집쥐에서는 처음 발견되었기에 형태학적 특징의 기술과 더불어 보고하고자 한다. E. revolutum은 충체가 길쭉하며 채장 5.3∼6.0mm, 체폭 1.0∼1.3mm이었다. 두극의 수는 모두 35∼37개이었으며 end group spine이 좌우에 각각 5개씩 있었다. 길다란 자궁은 굽어져 있었고 충란이 가득 들어 있었다. E. recurvatum도 충체가 긴쭉하였으며 체장 3.5∼4.7mm이었고 체폭 0.50∼0.65mm이었다. 두극의 수는 모두 45개이었으며, 복측 양단에 위치한 end group spine이 각각 4개씩 있었다. 짧은 자궁 내에는 소수(10개 미만)의 충란이 들어 있었다. 이상의 결과로 국내의 집쥐가 자연계에서 E. revolutum과 E. recurvatum의 종숙주 역할을 하고 있음을 확인하였다.

• Parasites, Hosts and Diseases
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• 제32권4호
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• pp.215-222
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• 1994

요코가와흡충 감염시 장상피내 림프구(inkaepithelial Iympho%rotes: IEL)의 증감과 장 병변의 상관관계를 알아보기 위하여 흰쥐(Sprague-Dawley)에 피낭유충을 실험 감염시킨 다음 5일 부터 70일까지 소장 점막에서 IEL 수와 위치, V/C ratio(villus/crypt ratio; 융모/선와의 비) 등을 관찰하였다. 피낭유충은 은어(Plecoglossus altivelis)에서 획득하여 흰쥐 15마리에 각각 3,000개씩 경구 감염시켰고 동일계 흰쥐 3마리를 비감염 대조군으로 사용하였다 감염 5일, 10일, 15일, 24 일 및 70일에 각각 3마리씩 희생시킨 다음 소장 여러 부위에서 조직을 획득하여 절편으로 제작하였고, Giemsa 염색한 후, 병리학적 관찰과 함께 IEL수 및 위치의 변동을 경시적으로 관찰하였다. 응모 위축과 선와 증식. V/C ratio의 감소 등을 특징으로 하는 장병변은 감염 후 5일에서 15일 사이에 가장 심하였으며 감염 24일째부터는 점차 회복되었다. IEL은 감염 초기에 일시적으로 증가하였으나, 장병변이 진행되면서 대조군보다 감소하였다가, 장병변의 회복과 함께 다시 증가하였다 대조군에서 IEL은 대부운 장상피층의 기저부에 위치하였으나, 감염 초기에는 많은 IEL이 장상괴세포의 핵주변부와 상층부에 분포하는 점이 특이하였다 이와 같이 요코가와흡충 감염시 나타나는 IEL수 및 위치의 변동은 장병변의 진행 과정과 밀접한 관련이 있음을 알 수 있었다.

• Parasites, Hosts and Diseases
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• 제50권2호
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• pp.173-176
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• 2012

Opisthorchis viverrini infection was found to be highly prevalent in 3 riverside villages (Ang Svay Chek A, B, and C) of the Prey Kabas District, Takeo Province. This area is located in the southern part of Cambodia, where the recovery of adult O. viverrini worms was recently reported. From May 2006 until May 2010, fecal examinations were performed on a total of 1,799 villagers using the Kato-Katz thick smear technique. In the 3 villages, the overall positive rate for helminth eggs ranged from 51.7 to 59.0% (av. 57.4%), and the percentage positive for O. viverrini was 46.4-50.6% (47.5%). Other helminths detected included hookworms (13.2%), echinostomes (2.9%), Trichuris trichiura (1.3%), Ascaris lumbricoides (0.6%), and Taenia spp. (0.06%). The prevalence of O. viverrini eggs appeared to reflect a lower infection in younger individuals (<20 years) than in the adult population (>20 years). Men (50.4%) revealed a significantly higher (P=0.02) prevalence than women (44.3%). The Ang Svay Chek villages of the Prey Kabas District, Takeo Province, Cambodia have been confirmed to be a highly endemic area for human O. viverrini infection.

• Parasites, Hosts and Diseases
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• 제54권4호
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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.

• 한국패류학회지
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• 제2권1호
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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.

• 농촌의학ㆍ지역보건
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• 제25권2호
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• pp.303-314
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• 2000

신안군 일부 섬지역에 거주하는 주민 224명에 대하여 장흡충 감염실태와 감염요인을 파악하기 위하여 설문조사와 대변에서의 장흡충 충란검사를 실시히여 다음과 같은 결과를 얻었다. 1. 조사대상자의 대변검사상 장흡충란양성률은 21.0%이었다. 2. 조사대상자의 장흡충란 양성률은 70세 이상에서 다른 연령군보다, 내륙지역보다 해안 지역에서, 농 수산에 종사하는자가 다른직업에 종사자보다 통계적요로 유의하게 높았다(P<0.05). 3. 연구대상자중 과거 음주자가 비음주자보다 장흡충 충란 양성률이 통계적으로 유의하게 높았고 현재 흡연자가 비흡연자에 비해 통계학적으로 유의하게 놓았다(P<0.05). 4. 장흡충 감염흡충은 장흡충의 중간 숙주인 숭어 생식자들에게서 통계학적으로 유의하게 높았다(P<0.01). 5. 연구대상자중 장흡충의 양성자 중에서 잦은 복통과 잦은 설사증상들이 통계학적으로 유의하게 높았다(P<0.05). 이상의 결과를 요약하면 전남 일부 섬지역의 장흡충 감염율은 여전히 높아 이에대한 진단 및 치료사업의 필요성이 충분하며, 해안지역 거주자, 고연령자, 음주, 흡연 그리고 생선회의 생식등이 관련이 있는 것으로 나타나 감염률을 낮추기 위해서는 이들 관련인자에 대한 우선적 접근이 필요하며 계속적인 관심과 관리가 이루어져야 할 것으로 생각한다.

• Parasites, Hosts and Diseases
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• 제55권5호
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• pp.523-532
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• 2017

A field survey studying intestinal parasites in humans and microbial pathogen contamination at environment was performed in a Laotian rural village to identify potential risks for disease outbreaks. A parasitological investigation was conducted in Ban Lak Sip village, Luang Prabang, Lao PDR involving fecal samples from 305 inhabitants as well as water samples taken from 3 sites of the local stream. Water analysis indicated the presence of several enteric pathogens, i.e., Aeromonas spp., Vibrio spp., E. coli H7, E. coli O157: H7, verocytotoxin-producing E. coli (VTEC), Shigella spp., and enteric adenovirus. The level of microbial pathogens contamination was associated with human activity, with greater levels of contamination found at the downstream site compared to the site at the village and upstream, respectively. Regarding intestinal parasites, the prevalence of helminth and protozoan infections were 68.9% and 27.2%, respectively. Eight helminth taxa were identified in fecal samples, i.e., 2 tapeworm species (Taenia sp. and Hymenolepis diminuta), 1 trematode (Opisthorchis sp.), and 5 nematodes (Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, trichostrongylids, and hookworms). Six species of intestinal protists were identified, i.e., Blastocystis hominis, Cyclospora spp., Endolimax nana, Entamoeba histolytica/E. dispar, Entamoeba coli, and Giardia lamblia. Questionnaires and interviews were also conducted to determine risk factors of infection. These analyses together with a prevailing infection level suggested that most of villagers were exposed to parasites in a similar degree due to limited socio-economic differences and sharing of similar practices. Limited access to effective public health facilities is also a significant contributing factor.

• Parasites, Hosts and Diseases
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• 제50권3호
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• pp.207-213
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• 2012

The egg morphology of minute intestinal flukes (MIF) that can occur as human infections in the Republic of Korea, i.e., Metagonimus yokogawai, M. miyatai, M. takahashii, Heterophyes nocens, Heterophyopsis continua, Stellantchasmus falcatus, Stictodora fuscata, Pygidiopsis summa, and Gymnophalloides seoi, was studied in comparison with Clonorchis sinensis. The adult worms were obtained from residents of endemic areas, and their intrauterine eggs were studied and measured using light microscopy; the length, width, length-width ratio (LWR), and Faust-Meleney index (FMI). Several specimens were processed for scanning electron microscopy (SEM), and before gold-coating, the uterine portion of each fluke was etched with a sharp pin in order to expose the eggs. The MIF eggs were ovoid, pyriform, or elliptical with a size range of $21-35{\times}12-21{\mu}m$. S. fuscata eggs revealed the highest FMI (largest in the area) and lowest LWR, whereas P. summa eggs showed the lowest FMI and medium LWR. SEM revealed that G. seoi and S. fuscata had remarkably clean shell surface lacking the muskmelon-like structure which is prominent in C. sinensis eggs. In Metagonimus spp., H. continua, H. nocens, and S. falcatus eggs, minute surface ridges were recognizable though less prominent compared with C. sinensis. On the surface of P. summa eggs, thread-like curly structures were characteristically seen. The results revealed that important differential keys for MIF eggs include the length, width, area (FMI), shape of the eggs, and the extent of the muskmelon-like structure or ridges on their shell surface and operculum.