• Journal of fish pathology
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• v.31 no.2
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• pp.123-129
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• 2018

Parvicapsula anisocaudata, a myxosporean parasite, is presumably one of causative agents of emaciation in olive flounder Paralichthys olivaceus in Korea. In this study, we report a case of unusual abdominal distension due to exceptionally enlarged liver in farmed olive flounder. For the identification of the causative agent, bacteria and nucleic acids of virus that are possibly present were attempted to isolate from internal organs of five fish sampled from a fish farm in Jeju. Although a few bacterial colonies were isolated from some samples, there was no evidence that fish were primarily affected by virus and/or bacteria. From histopathological analysis, myxosporean were found in almost all internal organs, particularly in the stomach. The causative agent was identified as P. anisocaudata by sequencing a part of small subunit rRNA. This study contains a very unusual case of olive flounder heavily and systemically infected with P. anisocaudata, showing excessively enlarged liver with a small amount of ascitic fluid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.539-546
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• 2019

The major cultured marine fishes in sea off the coast Gyeongsangnam-do Province, South Korea, were assessed and included 9.3% rockfish Sebastes schlegelii, 7.8% red seabream Pagrus major, and 2.1% rock bream Oplegnathus fasciatus. The number of insurance payments related to disease mortality in cultured fish in 2017 was fourfold that in 2016. Economic loss in aquaculture due to disease in cultured fish is high and represents an important inhibitory factor affecting marine fishery productivity. In 2018, diseases led to severe production losses in several aquaculture species: 40.0% in rockfish, 11.4% in olive flounder Paralichthys olivaceus, 10.0% in filefish Thamnaconus modestus, and 9.3% in red seabream. Fish-parasitic pathogens such as Microcotyle sebastis, Alella spp., and Dactylogyrus spp. enter mainly via the gills and skin surface. Among bacterial pathogens, Vibrio species were most common, with Vibrio harveyi being the dominant species causing infections in these fishes. The bacterium Lactococcus garvieae is thought to exhibit host specificity in fish. The fish species in the present study exhibited a higher tendency for infection by heterologous pathogens than by a single pathogen; therefore, it is necessary to devise new strategies for treating diseases in cultured fish.

• Journal of fish pathology
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• v.9 no.2
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• pp.119-126
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• 1996

We report on the variation of infection and histopathological change of Microcotyle sebastisci parasitic on cultured rockfish, Sebastes schlegeli, in Namhae Islands and Kamak Bay from April to October in 1995. Microcotylosis due to Microcotyle sebastisci occurred among cultured rockfish, Sebastes schlegeli. This parasite was not found on the host fish from June to July. Parasite sites were mainly consist of 2nd and 3rd gill arch`s filaments of rockfish. Also, the sites were secreted in large quantity of mucus with a very small bleeding. In Namhae Islands, maximum values of prevalence, relative density and mean intensity were found on September 1995, as 40.0%, 30.7 and 76.8, respectively. In Kamak Bay, maximum values of prevalence, relative density and mean intensity were obtained on October 1995, as 46.0%, 40.5 and 88.0, respectively. Histopathological changes of the heavily infested gills were showed necrosis, epithelium of the gill filaments underwent hyperplasia with fusion of the lamella and filamental clubbing. And a bacterial colony is invaded on the surface of lamella epithelium.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.171-176
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• 2001

Western blot analysis was performed to diagnose vivax malaria using stage-specific recombinant antigens. Genomic DNA from the whole blood of a malaria patient was used as templates to amplify the coding regions for the antigenic domains of circumsporozoite protein (CSP-1), meroxoite surface protein (MSP-1), apical merozoite antigen (AMA- 1), serine repeat antigen (SERA), and exported antigen (EXP- 1) of Plasmodium vivax. Each amplified DNA fragment was inserted into a pGEX-4T plasmid to induce the expression of GST fusion protein in Escherichia coli by IPTG. The bacterial cell extracts were separated on 10% SDS-PAGE followed by western blot analysis with patient sera which was confirmed by blood smear examination. When applied with patient sera, 147 (91.9%) out of 160 vivax malaria, 12 (92.3%) out of 13 falciparum malaria, and all 9 vivax/falciparum mixed malaria reacted with at least one antigen, while no reactions occurred with 20 normal uninfected sera. In the case of vivax malaria, CSP-1 reacted with 128 (80.0%) sera, MSP-1 with 102 (63.8%), AMA-1 with 128 (80.0%), SERA with 115 (71.9%), and EXP-1 with 89 (55.6%), respectively. We obtained higher detection rates when using S antigens (91.9%) rather than using each antigen solely (55.6 - 80%), a combination of 2 (76.3 - 87.5%), 3 (85.6 - 90.6%), or 4 antigens (89.4 - 91.3%). This method can be applied to serological diagnosis, mass screening in endemic regions, or safety test in transfusion of prevalent vivax malaria.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1992.07a
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• pp.7-19
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• 1992

Fish pathology is one of the main scientific bases upon which this expansion in aquaculture has been dependent and requires a wide knowledge of the environmental constraints, the physiology and characteristics of the various pathogens, the responses of the host and the methods by which they may be controlled. The primary disease and parasite problems in aquaculture animals relate to viral, bacterial, fungal and protozoan epizootics. Parasitic nematodes, trematodes and cestodes are commonly found in aquaculture animals, but seldom are they present in concentrations sufficinet to cause significant problems. When an epizootic does occur and chemical treatment is indicated, the appropriate chemical must be selected and properly applied. We have antibiotics, sulfa, nitrofuran and other chemicals for treatment of fish diseases. Some may be mixed with the fred during formulation, added to the pellets of feed as a surface coating, given in the dorm of an injection or used as a bath. Even though a drug or chemical has been officially approved for use in aquaculture, the substance should never be used unless there is a clear need. Some of the reasions for this view are as follows: (1) the constant use of antibiotics can lead to the development of resistant strains of bacteria, (2) biofilter efficiency may be impaired or destroyed by chemicals added to closed recirculating water systems, and (3) the injudicious use of chemicals can have a damaging effect on the environment as well as on human.

• The Journal of the Korean Society for Microbiology
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• v.35 no.1
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• pp.87-95
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• 2000

Staphylococcus aureus infections are often life-threatening. Relatively little is known about the host response to these infections, in particular, the implication of apoptosis induced by this microorganism. In this study, we have shown that S. aureus was cytotoxic to J774A.1 cell, a murine macrophage cell line. The cell death mediated by S. aureus occurred through apoptosis, as shown by increase in the proportion of fragmented host cell DNA. Although phagocytosis and NO production had important role in the induction of apoptosis, the contact between bacteria and host cells was not essential for this pathway. A certain bacterial product could also induce typical caspase-dependent apoptosis of J774A.1 cell. It is expected that new interpretation may be possible to host-parasite relationship based on these results.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3391-3394
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• 2016

Background: Helicobacter pylori is now recognized as a causative factor of chronic gastritis, gastroduodenal ulcers, gastric cancer and mucosa-associated lymphatic tissue lymphoma. Toll-like receptors are important bacterial receptors in gastric epithelial cell signaling transduction and play critical roles in gastric carcinogenesis. Materials and Methods: A total of 400 patients undergoing esophagogastroduodenoscopy for investigation of chronic abdominal pain were genotyped for single-nucleotide polymorphisms (SNPs) in TLR1 (rs4833095) using TagMan SNPs genotyping assay by real-time PCR hybridization. Relationships with susceptibility to H. pylori infection and pre-malignant gastric mucosa morphological patterns, classified by magnifying NBI endoscopy, were investigated. Results: The percentages of TLR1 rs4833095, CC homozygous, CT heterozygous and TT homozygous cases were 34, 46.5 and 19%, respectively. CC showed statistical differences between H. pylori positive and negative cases (P<0.001). CT and TT correlated with type 1 and type 2 gastric mucosal morphological patterns (P <0.01) whereas CC correlated with types 3 and 4 (P<0.01). Conclusions: This study demonstrated good correlation of TLR1 rs4833095 genotype with severity of inflammation in H. pylori infected gastric mucosa according to gastric mucosal morphologic patterns with magnifying NBI endoscopy.

• Parasites, Hosts and Diseases
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• v.59 no.3
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• pp.227-233
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• 2021

Eosinophilic meningitis is defined as the presence of more than 10 eosinophils per µl in the cerebrospinal fluid (CSF), or eosinophils accounting for more than 10% of CSF leukocytes in patients with acute meningitis. Parasites are the most common cause of eosinophilic meningitis worldwide, but there is limited research on patients in Korea. Patients diagnosed with eosinophilic meningitis between January 2004 and June 2018 at a tertiary hospital in Seoul, Korea were retrospectively reviewed. The etiology and clinical characteristics of each patient were identified. Of the 22 patients included in the study, 11 (50%) had parasitic causes, of whom 8 (36%) were diagnosed as neurocysticercosis and 3 (14%) as Toxocara meningitis. Four (18%) patients were diagnosed with fungal meningitis, and underlying immunodeficiency was found in 2 of these patients. The etiology of another 4 (18%) patients was suspected to be tuberculosis, which is endemic in Korea. Viral and bacterial meningitis were relatively rare causes of eosinophilic meningitis, accounting for 2 (9%) and 1 (5%) patients, respectively. One patient with neurocysticercosis and 1 patient with fungal meningitis died, and 5 (23%) had neurologic sequelae. Parasite infections, especially neurocysticercosis and toxocariasis, were the most common cause of eosinophilic meningitis in Korean patients. Fungal meningitis, while relatively rare, is often aggressive and must be considered when searching for the cause of eosinophilic meningitis.

• Food Science and Preservation
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• v.14 no.1
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• pp.35-41
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• 2007

As the consumption of environmentally friendly agricultural products increases, food safety is at the forefront of public health concerns. We analyzed the biological hazards of 26 species of leaf vegetables and 4 species of fruit according to types of cultivation (conventional or organic filming) and distribution system (giant retailers or organic food stores) using various culture media, automatic bacterial identification systems, and microscopy, Total bacterial count of unwashed agricultural product ranged from $5.2{\times}10^{3}\;to\;1.5{\times}10^{5}\;CFU/mL$ (from 0.1 g of agricultural products), and the average count dropped 25-fold (range, 8-60-fold) after water washing. Microbial levels of washed organic agricultural products were $6.0{\times}10^{2}-1.9{\times}10^{4}\;CFU/mL$, and were not significantly different f개m the microbial loads on conventionally farmed produce. There was no significant difference in bacterial count from agricultural produce purchased from giant retailers or organic food stores. Total microbial count of Chinese cabbage, welsh onion, red chicory and kale were comparatively high, and Enterobacter cloacae was isolated most frequently. Parasites were detected in agricultural products purchased from conventional farm products in the stores of giant retailers, and in organic food stores, and parasite prevalence was especially high in Chinese cabbages and welsh onion. The study indicated that cultivation methods and distribution systems did not cause significant differences in biological contamination levels of agricultural produce. Some vegetables and fruits were highly contaminated effective sanitizing methods to reduce these biological hazards are needed.

• The Journal of the Korean Society for Microbiology
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• v.34 no.6
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• pp.519-532
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• 1999

Helicobacter pylori is a causative agent of type B gastritis and plays a central role in the pathogenesis of gastroduodenal ulcer and gastric cancer. To elucidate the host-parasite relationship of the H. pylori infection on the basis of molecular biology, we tried to evaluate the genomic diversity of H. pylori. An ordered overlapping bacterial artificial chromosome (BAC) library of a Korean isolate, H. pylori 51 was constructed to set up a genomic map. A circular physical map was constructed by aligning ApaI, NotI and SfiI-digested chromosomal DNA. When the physical map of H. pylori 51 was compared to that of unrelated strain, H. pylori 26695, completely different restriction patterns were shown. Fifteen known genes were mapped on the chromosome of H. pylori 51 and the genetic map was compared with those of strain 26695 and J99, of which the entire genomic sequences were reported. There were some variability in the gene location as well as gene order among three strains. For further analysis on the genomic diversity of H. pylori, when comparing the genomic structure of 150 H. pylori Korean isolates with one another, genomic macrodiversity of H. pylori was characterized by several features: whether or not susceptible to restriction digestion of the chromsome, variation in chromosomal restriction fingerprint and/or high frequency of gene rearrangement. We also examined the extent of allelic variation in nucleotide or deduced amino acid sequences at the individual gene level. fucT, cagA and vacA were confirmed to carry regions of high variation in nucleotide sequence among strains. The plasticity zone and strain-specific genes of H. pylori 51 were analyzed and compared with the former two genomic sequences. It should be noted that the H. pylori 51-specific sequences were dispersed on the chromosome, not congregated in the plasticity zone unlike J99- or 26695-specific genes, suggesting the high frequency of gene rearrangement in H. pylori genome. The genome of H. pylori 51 shows differences in the overall genomic organization, gene order, and even in the nucleotide sequences among the H. pylori strains, which are far greater than the differences reported on the genomic diversity of H. pylori.