• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.468-475
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• 2017

This study is for the consideration of the existence tendency of Kudoa septempunctata in olive flounder. In general, muscle has shown a strong PCR positive reaction in spores containing tissues rather than non-containing tissues. However, blood PCR results showed opposed tendency. In various organs of the tested fish containing spores in muscle tissue, heart had shown positive reaction along with muscle at PCR analysis. Muscle fiber necrosis was observed at the histological observation, and this degeneration was common in both samples. The one sample was the PCR positive muscle containing spore and the other was the PCR positive muscle non-containing spore. Both of muscle tissues indicated a positive reaction at ISH (in-situ hybridization) against K. septempunctata.

• Fisheries and Aquatic Sciences
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• v.24 no.8
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• pp.277-283
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• 2021

Kudoa septempunctata has been reported as a new parasite in aquacultured olive flounder Paralichthys olivaceus, and also as a causative agent of food poisoning in humans. This paper investigated the infection of K. septempunctata in 216 sashimi and 20 sushi made of olive flounders in Busan, Korea. Among 236 samples, K. septempunctata was detected in eleven sashimi with 6-7 polar capsules by the microscopy. Among eleven sashimi, five sashimi were positive in Polymerase Chain Reaction (PCR) assay with the targets of 18S rDNA and 28S rDNA. The genotype of all the five PCR results is identified as the genotype ST3 which is common in Korea. K. septempunctata was found in olive flounders sashimi from Samcheonpo and Wando outside of Jeju Island. These findings would contribute to establish the standard of K. septempunctata for preventing food-borne outbreaks in advance and providing further preventive management for the seafood safety.

• Journal of fish pathology
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• v.37 no.1
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• pp.89-96
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• 2024

Kudoa septempunctata, a myxozoan parasite, usually presents without any signs and primarily infects adult fish. The invasive diagnostic methods, such as tissue biopsy, can identify pathogens, but cause economic losses because they require killing the fish. In this study, we conducted a monitoring of four fish farms located on Jeju Island, to investigate the potential for non-invasive diagnosis of K. septempunctata using hyperspectral cameras. It provides spectral information from R000_B000_G000 to R255_B255_G255 for a total of 3,282 olive flounder (Paralichthys olivaceus). Each object is imaged with 2,000 data points, allowing comprehensive spectral analysis by comparing images obtained from negative control objects to positive control objects. Noticeable differences were observed in the brightness or pallor of the positive control images. This suggests the potential utility of hyperspectral imaging as a non-invasive diagnostic tool for detecting K. septempunctata infections in fish populations.

• BMB Reports
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• v.53 no.9
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• pp.478-483
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• 2020

Kudoa septempunctata is a myxozoan parasite that causes food poisoning in individuals consuming olive flounder. The present study aimed to investigate the currently insufficiently elucidated early molecular mechanisms of inflammatory responses in the intestine owing to parasite ingestion. After Kudoa spores were isolated from olive flounder, HT29 cells were exposed to spores identified to be alive using SYTO-9 and propidium iodide staining or to antigens of Kudoa spores (KsAg). IL-1β, IL-8, TNF-α and NFKB1 expression and NF-κB activation were assessed using real-time PCR, cytokine array and western blotting. The immunofluorescence of FITC-conjugated lectins, results of ligand binding assays using Mincle-Fc and IgG-Fc, CLEC4E expressions in response to KsAg stimulation, and Mincle-dependent NF-κB activation were assessed to clarify the early immune-triggering mechanism. Inflammatory cytokines (IL-1β, GM-CSF and TNF-α), chemokines (IL-8, CCL2, CCL5 and CXCL1) and NF-κB activation (pNF-κB/NF-κB) in HT29 cells increased following stimulation by KsAg. The immunofluorescence results of spores and lectins (concanavalin A and wheat germ agglutinin) suggested the importance of Mincle in molecular recognition between Kudoa spores and intestinal cells. Practically, data for Mincle-Fc and KsAg binding affinity, CLEC4E mRNA expression, Mincle immunofluorescence staining and hMincle-dependent NF-κB activation demonstrated the involvement of Mincle in the early immune-triggering mechanism. The present study newly elucidated that the molecular recognition and immune-triggering mechanism of K. septempunctata are associated with Mincle on human intestinal epithelial cells.

• Fisheries and Aquatic Sciences
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• v.20 no.8
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• pp.16.1-16.8
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• 2017

The exportation of cultured olive flounder (Paralichthys olivaceus) in Korea has been recently decreasing due to the infections with a myxozoan parasite Kudoa septempunctata, and there is a strong demand for strict food safety management because the food poisoning associated with consumption of raw olive flounder harbouring K. septempunctata has been frequently reported in Japan. The life cycle and infection dynamics of K. septempunctata in aquatic environment are currently unknown, which hamper establishment of effective control methods. We investigated sea water and marine invertebrates collected from olive flounder farms for detecting K. septempunctata by DNA-based analysis, to elucidate infection dynamics of K. septempunctata in aquaculture farms. In addition, live marine polychaetes were collected and maintained in well plates to find any possible actinosporean state of K. septempunctata. The level of K. septempunctata DNA in rearing water fluctuated during the sampling period but the DNA was not detected in summer (June-July in farm A and August in farm B). K. septempunctata DNA was also detected in the polychaetes Naineris laevigata intestinal samples, showing decreased pattern of 40 to 0%. No actinosporean stage of K. septempunctata was observed in the polychaetes by microscopy. The absence of K. septempunctata DNA in rearing water of fish farm and the polychaetes N. laevigata intestinal samples during late spring and early summer indicate that the infection may not occur during this period. N. laevigata was suspected as the possible alternate invertebrate host of K. septempunctata, but the actinosporean stage was not found by well plate method and further studies will be necessary. This research provides important baseline information for understanding the infection dynamics of K. septempunctata in olive flounder farms and further establishment of control strategies.

• Journal of Environmental Health Sciences
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• v.46 no.2
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• pp.184-191
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• 2020

Objectives: This study was performed to analyze cases of food poisoning outbreaks reported in Chungcheongnamdo Province in 2019 and report it as effective data for preventing food poisoning in the future. Methods: Food poisoning outbreaks were analyzed to detect virus, bacteria, and protozoa according to the Manual for Detection of Foodborne Pathogens in Outbreaks to clarify the causes of food poisoning that occurred in Chungcheongnam-do Province in 2019. Results: Among the 79 cases of food poisoning outbreaks, 59 cases (74.7%) were in general restaurants, 15 cases (19.0%) in food service institutions, three cases at banquets, and two cases in take-out food. The 42 cases at general seafood restaurants made up the majority of food poisoning in Chungcheongnam-do. Food poisoning pathogens were shown in 13 cases (86.7%) out of the 15 cases at food service institutions, and 10 cases were related to Norovirus. Among the 79 cases, food-borne pathogens were identified in 35 cases of outbreaks, accounting for 44.3%. The confirmed pathogens were as follows: bacteria (24 cases), Norovirus (12 cases) and Kudoa septempunctata. (five cases). The food-borne bacteria were pathogenic E. coli (12 cases), Staphylococcus aureus (six cases), Salmonella spp. (two cases), Campylobacter jejuni, Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus (one case). Conclusions: To prevent food poisoning, it is necessary to analyze regional characteristics and environments and to hold a campaign for the prevention of food poisoning based on that analysis. In addition, when food poisoning occurs, the results of analyzing its cause and spread based on accurate epidemiological survey need to be shared.

• Korea Trade Review
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• v.44 no.6
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• pp.119-134
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• 2019

This study focuses on a recent WTO SPS dispute related to Korea Import Bans and Testing and Certification Requirements for Radionuclides (DS495) in order to learn from the case and take proactive measures to prevent potential import restrictions by Japan on Korean seafood. Korean-Radionuclides (Japan) emphasizes the importance of sufficient scientific evidence, especially scientific information from relevant international organizations, in an effort to take preventive measures towards Japan's restrictions on Korean seafood imports. Japan claims that a novel parasite, Kudoa septempuctata, in Korean flatfish causes food poisoning. As food poisoning is a serious concern, there is a low possibility that Japan's enhanced monitoring measures would be more trade restrictive than required as prescribed in Article 5.6 of the WTO SPS Agreement. In addition, Korea is the biggest exporter of olive flounder to Japan. Hence, the possibility that similar conditions could be established is low in relation to non-discriminatory principles under the WTO SPS Agreement. Accordingly, we should collect relevant scientific evidence, improve domestic sanitary management of fishery products, and seek export diversification so that we prepare for potential import restrictions by Japan and minimize implications.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.660-667
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• 2021

In recent years, myxosporean infection from the cultured olive flounders Paralichthys olivaceus, have been frequently observed in Jeju island, South Korea. This study aimed to compare histopathological and molecular-biological methods of examining myxosporean infection from these flounders. Samples were obtained from affected individuals exhibiting emaciation or abdominal distention and a polymerase chain reaction (PCR) indicative of Parvicapsular anisocaudata, Enteromyxum leei and Kudoa septempunctata were initiated. Histopathological examination were conducted with H&E stained tissue sections, and then in-situ hybridization (ISH) reaction were processed with selected sections using P. anisocaudata, E. leei, K. septempunctata and Scuticociliate probes. Renal and intestinal tissue degeneration were common symptoms associated with all samples. Sever glomerular and renal tubular degeneration were evident, as were intestinal epithelial desquamation and spore formation in the epithelial cells. The results of conventional PCR analysis and ISH reactions revealed differences, and we suspect that various microparasites may have been associated with the symptoms manifested.