• Korean Journal of Veterinary Research
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• v.9 no.1
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• pp.71-78
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• 1969

The present studies were undertaken to determine accurately whether Korean native fresh-water shrimps can serve as the second intermediate host of Clonorchis sinensis. The experimental results obtained were as follows; 1. Metacercaria of Clonorchis sinensis was not discovered in 36 Macrobranchium nipponensis (De Hann), 1992 Palaemon paucidens (De Hann) and Palaemon madestus Heller, and 860 Caridina leucastica Stimpson, collected in Kimhae district, which were digested in artificial gastric juice, using binocular dissecting microscope. 2. Cercariae of the Chinese liver fluke could not approach the body wall of young shrimps due to streaming caused by their motion. 3. Young Palaemon spp. of 247 were divided into two groups and placed in two different room aquariums, one is at high temperature, the other is normal. Then they were contacted with the cercariae. Only 11 degenerated metacercariae were found in 9 Palaemon spp. It was suggested that they had died immediately or within a few days after penetration. Furthermore the temperature did not affect the infective ratio. 4. At the field experimental aquarium, no metacercaria of Clonorchis sinensis was discovered tn 100 Palaemon spp. which had been brought into contact with 5000 Parafossarulus manchouricus two trials. 5. Specific changes in the cercariae mixed with the extract of shrimps meat were not observed through the dissecting microscope. 6. These results suggest that the Korean native shrimps cannot serve as the intermediate host of Clonorchis sinensis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.47-53
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• 2018

The presence of pathogens in wild fish is a potential threat to the fish being raised nearby fish farm. Surveillance of these pathogens in the wild is, thus, highly important to keep fish in the farm safe from serious communicable diseases. Fish and crustacean were sampled 4 times at Soyang Lake in 2016. Pathogens for five reportable communicable diseases including KHVD (koi herpesvirus disease), SVC (spring viraemia of carp), EUS (epizootic ulcerative syndrome) and WSD (white spot disease), and parasites were investigated. In Soyang Lake, pale chub Zacco platypus was the most abundant. Forty seven pale chub, 8 Korea piscivorous chub Opsarichthys uncirostris, 3 oily shiner Sarcocheilichthys variegatus wakiyae and 2 crucian carp Cyprinus carassius were investigated for detection of target diseases of fish. Seventeen Caridina denticulata denticulata, 12 Oriental river prawn Macrobrachium nipponense and 1 Chinese mitten crab Eriocheir sinensis were used for detection of WSD. As the result, reportable communicable diseases were not detected in all the freshwater animals. Dactylogyrus was detected in Korea piscivorous chub. Copepoda was also detected in pale chub and Korea piscivorous chub. Metacercaria was detected in the pale chub sampled in September and October. Those were not metacercaria of liver fluke Clonorchis sinensis.

• Korean Journal of Veterinary Service
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• v.31 no.2
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• pp.207-217
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• 2008

This study was carried out to investigate the prevalence of fascioliasis of slaughtered and farmed cattle in Gwangju area from February to November in 2007. A total of 1,000 cattle fecal samples were collected from slaughter houses (n=805) and farms (n=185). Twelve (1.2%) were found as positive cases with excretion of the egg of Fasciola spp in the fecal specimens, and 128 (12.8%) were positive in intestinal parasitism using the flotation and sedimentation procedures. The infection rate of fluke larvae from the slaughtered cattle at abattoirs in Gwangju was 0.75% (6 out of 805 heads). In histopathology, there were several liver lesions such as inflammation with infiltration of eosinophil, polymorphonuclear cells, mononuclear cells and multinucleated giant cells, proliferation of connective tissue, calcification and abscess formation.

• Parasites, Hosts and Diseases
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• v.57 no.3
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• pp.299-302
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• 2019

A clonorchiasis case in a captive leopard cat, Prionailurus bengalensis euptilurus, was confirmed by ultrasonographic findings and egg morphologies found in the bile juice sample in the Korea. The leopard cat was introduced from the wild habitat of Gyeongsangnam-do, to Cheongju Zoo in Cheongju-si, Chungcheongbuk-do, Korea in August 2014. Physical examinations were basically performed for quarantine and check-up health. The cat was comparatively good in health except anorexia. The cyst-like bile duct dilation and the increased echogenicity of gall bladder wall and hepatic parenchyma were observed by ultrasonography. Ultrasound-guided needle biopsy was conducted for collecting bile juice and the specimens were observed under light microscope. The numerous small trematode eggs were detected in the bile juice sample of the light microscopy. The eggs were $25-33(28{\pm}3){\mu}m$ by $18-22(20{\pm}1){\mu}m$ in size and showed typical characteristics of Clonorchis sinensis egg, i.e., a dominantly developed operculum, shoulder rim and dust-like wrinkles in surface. To treat the liver fluke infection, 20 mg/kg of praziquantel was orally administered only once to the case. Follow-up studies including fecal examinations were conducted during 2 years after treatment. But no more eggs were detected from the case. In the present study, we described the first clonorchiasis case of leopard cat, which was confirmed by ultrasonographic findings and egg morphologies from the bile juice sample in Korea.

• Pediatric Infection and Vaccine
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• v.8 no.1
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• pp.123-128
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• 2001

Clonorchiasis, known as the parasitic fluke in the intrahepatic bile ducts, occurs throughout Korea, Japan, Taiwan, and Vietnam with high frequency. Most of the infections follow the consumptions of raw or undercooked freshwater fish, which explains its rare occurrence to childhood even in those areas mentioned earlier above. The authors have experienced it with an 8 year old boy. Abdominal ultrasonogram revealed multiple low echogenic nodules in the right lobe of liver and lymph nodes proliferation around the porta hepatis area. And abdominal C.T. scan also found multiple low attenuated nodules with delayed enhancement in liver parenchyma with hepatomegaly and multiple conglomerated lymph nodes in porta hepatis. Both abdominal ultrasonogram and C.T. scan didn't show any dilatation of peripheral intrahepatic bile ducts. In repeated stool examination, Clonorchis sinensis eggs were found in feces and the result of the skin test for Clonorchis sinensis was positive. The patient had a history of having eaten raw pond smelt back in Cheongju a month before the symptom onset. On the basis of the patient's history and the fact that Clonorchis eggs were found in feces 3 weeks after eosinophilia and symptoms were noted, the authors estimated that the findings of the patient's abdominal sonogram and C.T. scan were the radiologic findings of the acute phase of clonorchiasis, of which no report had ever been made before. So the authors report a case of clonorchiasis with atypical radiologic findings in an 8 year old boy.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.306-315
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• 2019

The estuary of the Han River constantly suffers from pollutants and pathogenic microorganisms which could cause serious damage to aquatic organisms living there. Despite of this potential risk, it is hard to find any reliable scientific reports on the status of reportable disease infection to the organisms living in this area. In this study, cyprinid fish and crustaceans in Jeonryu-ri, a region of the Han River estuary, were investigated for the infection by representative reportable communicable diseases(SVC, spring viraemia of carp; KHVD, koi herpesvirus disease; EUS, epizootic ulcerative syndrome; WSD, white spot disease) and parasites. Peripheral fish and primary freshwater fish were observed in Jeonryu-ri with cyprinid caught most frequently. Crustaceans were mostly marine species. No positive bands to any of the reportable diseases were produced in any of the fish and crustacean examined in this study by PCR. No trace of Clonorchis sinensis, a liver fluke potential threat to human health, was detected in any of fish samples. However, many fish were infected by metacecaria of other flukes, and other various parasites such as nematode, cestode, copepod, monosite and acanthocephalan. These results suggest that important aquatic organisms in the Han River estuary is not seriously polluted yet. However, it is important to keep monitoring the diseases since the water quality in this region is constantly changing, and devastating influence of infectious diseases is unpredictable. Further, it is required to expand monitoring area toward upstream and increase the number of fish for examination.

• Parasites, Hosts and Diseases
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• v.51 no.6
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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.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.299-304
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• 2014

Cholangiocarcinoma (CCA), a malignancy of biliary duct with a very poor prognosis, is the leading cause of cancer death in countries of the Mekong subregion. Liver fluke infection is the main etiological factor, but genetic variation has been recognized as also important in conferring susceptibility to CCA risk. Nuclear factor (erythroid derived 2)-like 2 (NRF2) is a key transcription factor in detoxification and antioxidant defense. Emerging evidence has demonstrated that genetic polymorphisms in the NRF2 gene may be associated with cancer development. The objectives of this study were to investigate the association of NRF2 genetic polymorphism with CCA risk and to evaluate the influence of the NRF2 genotype on survival time of affected patients. Single nucleotide polymorphisms (SNPs) of the NRF2 gene, including rs6726395: A/G, rs2886161: C/T, rs1806649: C/T, and rs10183914: C/T, were analyzed using TaqMan$^{(R)}$ SNP genotyping assays. Among 158 healthy northeastern Thai subjects, the allele frequencies were 41, 62, 94, and 92%, respectively. The correlation of NRF2 SNPs and CCA risk was analyzed in the 158 healthy subjects and 198 CCA patients, using unconditional logistic regression. The results showed that whereas the NRF2 SNPs were not associated with CCA risk (p>0.05), Kaplan-Meier analysis of 88 intrahepatic CCA patients showed median survival time with rs6726395 genotypes of GG and AA/AG to be $344{\pm}138$ (95%CI: 73-615) days and $172{\pm}37$ (95%CI: 100-244) days, respectively, (p<0.006). On multivariate Cox proportional hazard analysis, the GG genotype of rs6726395 was found to be associated with longer survival with a hazard ratio of 0.54 (95%CI: 0.31-0.94). In addition, non-papillary adenocarcinoma was associated with poor survival with a hazard ratio of 2.09 (95%CI: 1.16-3.75). The results suggest that the NRF2 rs6726395 polymorphism can be a potential prognostic biomarker for CCA patients.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.21-30
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• 1991

An immunohistochemical study was performed to demonstrate comparative antigenicity of each body structure of the liver fluke, Clonorchis sinensis, such as the digestive tract, reproductive organs, excretory system, tegument and suckers. Indirect immunoperoxidase technique was applied, rising formalin-fixed and paraffin-embedded sections of C. sinensis as the antigen. Pooled cat sera obtained 10 weeks after an experimental infection with C. sinensis and peroxidase-conjugated goat anti-cat IgG were used as the primary and secondary antibodies, respectively. The intensity of immunohistochemical stain was very sensitive upon the titers of the primary and secondary antibodies, and their optimum dilutions were found to be 1:1,000∼1:2,000 and 1:1,000, respectively. The intestinal epithelial cells, intestinal content and excretory bladder showed strong positive coloring reactions even at lower titer (1 : 2,000) of the primary antibody, whereas the uterine wall and eggs, vitelline glands, and male reproductive organs showed only weak positive reactions despite an increase in the antibody titer (1:1,000). On the other hand, the suckers, tegument, subtegumental cells and other parenchyme portions did not reveal any positive immunoperoxidase reaction at the same antibody titers. From the above results, it is highly suggested that the most potent antigenicity of C. sinensis occur from their excretory-secretory substances originated from the digestive and excretory organs.