• BMB Reports
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• v.48 no.2
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• pp.103-108
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• 2015

Trichomoniasis caused by the parasitic protozoan Trichomonas vaginalis is the most common sexually transmitted disease in the world. Dendritic cells are antigen presenting cells that initiate immune responses by directing the activation and differentiation of naive T cells. In this study, we analyzed the effect of Trichomonas vaginalis-derived Secretory Products on the differentiation and function of dendritic cells. Differentiation of bone marrow-derived dendritic cells in the presence of T. vaginalis-derived Secretory Products resulted in inhibition of lipopolysaccharide-induced maturation of dendritic cells, down-regulation of IL-12, and up-regulation of IL-10. The protein components of T. vaginalis-derived Secretory Products were shown to be responsible for altered function of bone marrow-derived dendritic cells. Chromatin immunoprecipitation assay demonstrated that IL-12 expression was regulated at the chromatin level in T. vaginalis-derived Secretory Products-treated dendritic cells. Our results demonstrated that T. vaginalis- derived Secretory Products modulate the maturation and cytokine production of dendritic cells leading to immune tolerance.

• Parasites, Hosts and Diseases
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• v.45 no.1 s.141
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• pp.33-38
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• 2007

To know the prevalence of heterophyid trematodes among inhabitants of a southern coastal village, i.e., Sacho-ri, Gangjin-gun, Jeollanam-do(Province), 82 stool samples were examined on helminth eggs and protozoan cysts using Kato-Katz and formalin-ether sedimentation techniques. Total 33 people(40.2%) were positive for trematodes(Heterophyes nocens; 15 people, Pygidiopsis summa; 3, Metagonimus sp.; 4, Clonorchis sinensis; 7, Gymnophalloides seoi; 6) and/or protozoa(Entamoeba coli; 3). Among intestinal trematode egg positive cases, 17 were treated with praziquantel and their whole diarrheic stools were collected after purgation. Adult flukes of H. nocens(number of specimens=1,294), P. summa(386), Stellantchasmus falcatus(5), Stictodora lari(4), and Heterophyopsis continua(1) were collected using a stereomicroscope. To know the source of human H. nocens infections in this village, metacercarial infections in mullets(10) were examined and most H. nocens metacercariae(101/105, 96.2%) were found in the trunk portion. From above results, the surveyed coastal village has been newly known as an endemic focus of human H. nocens infection and consuming raw mullets was the presumable source of human heterophyid infections.

• Parasites, Hosts and Diseases
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• v.56 no.2
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• pp.205-210
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• 2018

Waterborne parasitic protozoa, particularly Giardia lamblia and Cryptosporidium spp., are common causes of diarrhea and gastroenteritis worldwide. The most frequently identified source of infestation is water, and exposure involves either drinking water or recreation in swimming pools or natural bodies of water. In practice, studies on Cryptosporidium oocysts and Giardia cysts in surface water are challenging owing to the low concentrations of these microorganisms because of dilution. In this study, a 3-year monitoring of Cryptosporidium parvum, Giardia lamblia, and Naegleria fowleri was conducted from August 2014 to June 2016 at 5 surface water sites including 2 lakes, 1 river, and 2 water intake plants. A total of 50 water samples of 40 L were examined. Cryptosporidium oocysts were detected in 22% of samples and Giardia cysts in 32%. Water at the 5 sampling sites was all contaminated with Cryptosporidium oocysts (0-36/L), Giardia cysts (0-39/L), or both. The geometric mean concentrations of Cryptosporidium and Giardia were 1.14 oocysts/L and 4.62 cysts/L, respectively. Thus, effective monitoring plans must take into account the spatial and temporal parameters of contamination because they affect the prevalence and distribution of these protozoan cysts in local water resources.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.116-126
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• 1984

The present study was designed to elucidate the recent prevalence of the intestinal protozoa and to demonstrate the relationship on prevalence of the surveyed population with their academic career and living conditions. During the period from May to July 1981, total 2, 735 fecal specimens were collected from the inhabitants of 11 areas in Gyeong-gi Do(province) near by Seoul City, and 6 areas in Jeonra Bug Do, southwestern part of Korea. The samples were fixed with SAF solution and were examined by formalin-ether sedimentation technique. The results are summarised as follows: 1, Overall positive rate of intestinal protozoa was 11. l% : Gyeong-gi Do, 10.7%; Jeonra Bug Do, 11.7%. 2. Five species of intestinal protozoa were detected: Entamoeba histolytica 0.69% : Entamoeba cali 5.52%; Endolimax nana 2.71%, Giardia lamblia 2.23%; lodamoeba biitschlii 0.18%. 3. Highest positive rates among the examined areas were recognized: Incheon City of Gyeong-gi Do, 26.7%; Im-sil Gun(county) of Jeonra Bug Do, 19.9%. 4. By species, E. nana showed the highest prevalence rate (13.74%) in Incheon City, and E. histolytica (2.37%) and E. coli (9.95%) in Im-sil Gun. 5. Prevalence of E. histolytica in rural areas was higher than in urban areas. 6. No significant difference in the prevalence rate by sect and age was recognized, although the group under 10 years and over 60 years were lower than in other age groups. 7, The highest positive rate of E. histolytica was observed in pauper group and significant linearity of prevalence rate of E. histozytica by monthly income was observed. 8. The inhabitants who used conventional latrine showed higher prevalence, 11.5%, than the group of inhabitants who used modified privy. 9. Although no significant difference of positive rate was recognized by academic career, but the lowest prevalence rate was observed in college graduates. 10. Over half of the surveyed population, 64.8% has no experience on anthelmintic practice. Number of anthelmintic application resulted no difference in prevalence. In conclusion, prevalences of intestinal protozoa in Gyeong-gi Do and Jeonra Bug Do decreased remarkably in comparison with those of one decade before. However, economic level, academic career and anthelmintic administration seemed no essential reasons for such declination.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.645-650
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• 2019

Despite differences in virulence between strains of Toxoplasma gondii, rapid and accurate genotyping methods are lacking. In this study, a method was developed to detect and genotype T. gondii in food and environmental samples using PCR and a novel peptide nucleic acid (PNA) melting array. An alignment of genome sequences for T. gondii type I, II, and III obtained from NCBI was generated, and a single nucleotide polymorphism analysis was performed to identify targets for PCR amplification and a PNA melting array. Prior to the PNA melting array, conventional PCR was used to amplify GRA6 of T. gondii. After amplification, the PNA melting array was performed using two different PNA hybridization probes with fluorescent labels (FAM and HEX) and quenchers. Melting curves for each probe were used to determine genotypes and identify mutations. A 214-bp region of the GRA6 gene of T. gondii was successfully amplified by PCR. For all T. gondii strains (type I, II, and III) used to evaluate specificity, the correct genotypes were determined by the PNA melting array. Non-T. gondii strains, including 14 foodborne pathogens and 3 protozoan parasites, such as Giardia lamblia, Cryptosporidium parvum, and Entamoeba histolytica, showed no signal, suggesting that the assay has a high specificity. Although this is only a proof-of-concept study, the assay is promising for the fast and reliable genotyping of T. gondii from food and environmental samples.

• 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.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1401-1408
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• 2017

Petiveria alliacea L. (Phytolacaceae) is a medicinal plant with a broad range of traditional therapeutic properties, including the treatment of dysentery and intestinal infections caused by protozoan parasites. However, its effects against Entamoeba histolytica have not been reported yet. We investigated the antiamoebic activity present in the leaves of P. alliacea Antiamoebic activity was evaluated in methanolic and aqueous extracts, as well as in the hexanic, methanolic, and EtOAc fractions. The P. alliacea methanolic extract showed a better antiamoebic activity than the aqueous extract with an $IC_{50}=0.51mg/ml$. Likewise, the hexanic fraction was the most effective fraction, showing a dose-dependent activity against E. histolytica, with an $IC_{50}=0.68mg/ml$. Hexanic subfraction 12-19 showed the highest antiamoebic activity at 0.8 mg/ml, producing 74.3% growth inhibition without any toxicity in mammal cells. A major component in subfraction 12-19 was identified as isoarborinol, which produced 51.4% E. histolytica growth inhibition at 0.05 mg/ml without affecting mammal cells. The P. alliacea leaf extract has antiamoebic activity that can be attributed to a major metabolite known as isoarborinol.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.677-681
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• 2003

Currently, both the indirect fluorescent antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA) have been used to detect Neospora caninum antibodies. Several factors such as the buffers, the conjugate, the pattern of fluorescence, and the cross reactivity with other apicornplexan protozoan, may result in poorly correlated data. The present study was undertaken to develop and evaluate the Neospora agglutination test (NAT) for the detection and quantification of IgG antibodies to N. caninum from various animal species. Compared to the ELISA method, the NAT with a cutoff value of 1:512 gave a high index of coincidence (kappa=0.807) and no cross reactivity to Toxoplasma gondii antiserum. Hence, this NAT method, which did not require a species-specific secondary antibody and expensive tools, would be easily available for the detection of antibodies to N. caninllm of various animal species.

• Journal of agricultural medicine and community health
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• v.15 no.1
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• pp.49-55
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• 1990

Zoonoses are those diseases and infections that are naturally transmitted between vertebrate animals and man. At present, approximately 175 diseases caused by virus, rickettsia, bacteria, protozoa and helminthes as well as some of arthropods and the number is continually increasing. Although zoonoses are generally recognized as significant health problems, the actual prevalence and incidence of zoonotic infections is difficult to determine. Medical services in a rural area are scarce and ill persons may have little chance to see a physician. Furthermore, a lack of physician awareness and of appropriate diagnostic support is made often misdiagnosis. In rural Korea, parasitic disease is still important subject in the field of zoonotic infections considering its number and morbidity. Recently there was conspicuous reduction of soil-transmitted parasitic diseases (i.e. ascariasis. hookworms, trichuriasis), but clonorchiasis. intestinal trematodiases and taeniasis are a considerable problem. This is often significantly related to human behavioral patterns based on socio-economic and cultural conditions and linked with the local biologic and physical environment. The most of all parasitic zoonoses to man and animals are the food-transmitted parasitic diseases, and domestic animals such as dog, cat, pig, as well as fat and some mammals, ruminants and birds are act as reservoir hosts. In the present topics, current problems of parasitic zoonoses caused by protozoan infections (i. e. toxoplasmosis, pneumocystosis and cryptosporidiosis) which are the most common opportunistic in AIDS or immunocompromised persons, trematode infections (i.e. clonorchiasis, paragonimiasis and some intestinal tremadodiases). cestode infections such as cysticercosis and sparganosis, and some nematode infections of anisakiasis, thelaziasis and strongyloidiasis, are discussed here those on the occurrence in man and animals and the source of transmission as well as prevention and control measures in Korea.

• Journal of Aquaculture
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• v.18 no.3
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• pp.207-214
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• 2005

We report on the diagnosis, pathology, and taxonomy of Perkinsus sp. infection in Manila clams (Ruditapes philippinarum) from Korean waters. Amplimers were designed from internal portions of the non-transcribed spacer (NTS) of P. atlanticus for molecular diagnosis of Perkinsus infection. PCR-based identification methods and an in situ hybridization assay were developed for detection of Perkinsus sp. in live tissues as well as in histological preparations. Hybridization signals were observed around the nucleus of trophozoites. Positive results from PCR and in situ hybridization indicated that Korean Perkinsus sp. is genetically identical with P. atlanticus reported in Europe, which is currently synonymous with P. olseni reported from Australia. Microscopic morphological features of different lift stages of Perkinsus sp. appeared very similar to those of P. atlanticus. Severely infected clams often exhibited white nodules on their mantles and gills as a consequence of inflammation. In lightly to moderately infected clams, Perkinsus sp. was mainly found in gill tissues, whereas the protozoan parasites were found in digestive tracts, gonadal tissues, and foot tissues of heavily infected clams. It is likely that the gills are the portal of the infection and that P. olseni spreads to other tissues as the infection advances. In conclusion, by considering the taxonomic priority of P. olseni, Korean Perkinsus sp. is accepted as P. olseni. P. olseni appears to be common on tidal flats on the western and southern Korean coasts and is considered to be a pathogen capable of causing mass mortality of clams.