• Parasites, Hosts and Diseases
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• v.57 no.4
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• pp.389-397
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• 2019

The infection status of Clinostomum complanatum metacercariae (CcMc) was broadly surveyed in fishes from water systems of Nakdong-gang (River) in the Republic of Korea (Korea) for 5 years. All 4,468 fishes collected were individually examined by the artificial digestion methods. No CcMc were detected in fishes from Naeseongcheon in Yecheongun, Gigyecheon in Gyeongju-si, Gyeongsangbuk-do, and Hamancheon in Haman-gun, Gyeongsangnam-do. In fishes from Wicheon in Gunwi-gun, Gyeongsangbuk-do, CcMc were detected in 180 (15.4%) out of 1,168 fishes and their intensity was 5.8 per fish infected. The prevalences with CcMc in positive fish species from 3 other surveyed areas, i.e., Banbyeoncheon in Yeongyang-gun, Nakdong-gang in Sangju-si and Hoecheon in Goryeong-gun, in Gyeongsangbuk-do were 19.3%, 33.3%, and 19.0% and their intensities were 1.5, 17.6, and 2.6 per fish infected respectively. In fishes from Yangcheon in Sancheong-gun, Gyeongsangnam-do, CcMc were detected in 811 (45.6%) out of 1,779 fishes examined and their intensity was 9.8 per fish infected. The prevalence was most high in Squalidus spp. (97.7%) and followed by acheilognathinid fish (66.8%), Pungtungia herzi (52.0%), rasborinid fish (39.6%) and Hemibarbus spp. (25.9%) from Yangcheon. The intensity was also most high in Squalidus spp. (27.0). The endemicity with CcMc was very low in fishes from water systems of Nakdong-gang in the east coast of Korea. Conclusively, it is confirmed that various fish species act as the second intermediate hosts of C. complanatum, and the endemicities of CcMc are more or less different by the fish species and group from Yangcheon, in Sancheong-gun, Gyeongsangnam-do, Korea.

• Entomological Research
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• v.48 no.6
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• pp.522-532
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• 2018

As the vector-borne diseases rapidly increased due to climate change, we investigated the incidence of flavivirus occurrence among female mosquito species in urban and rural study sites in Daegu and Gunwi, South Korea using Realtime PCR. We collected more individuals and more species of mosquito in 2016 than in 2015. In 2015, we recorded a total of 22,033 mosquitoes (Trap Index, 224.8) representing 10 species from 5 genera, whereas in 2016, a total of 27,137 mosquitoes (Trap Index, 278.7) representing 13 species from 6 genera were collected. The number of mosquitoes in 2016 was higher in all study sites, except in the migratory bird habitats where the number decreased. Of the 14 species collected over the two years, Aedes vexans nipponii and Anopheles spp. were dominant in the cowsheds in rural farmland; Culex pipiens complex, in urban residential areas; and, Anopheles spp. and Cu. pipiens complex in migratory bird habitats caught in a black light trap. Cu. pipiens complex and Ae. albopictus in urban parks and Ae. albopictus and Armigeres subalbatus in migratory bird habitats were the dominant species caught in BG-sentinel traps. We found that the number of mosquitoes was highest during July-September. We analyzed 1,725 pools to detect flavivirus, where Chaoyang virus was detected among Ae. vexans niponii collected from cowsheds in rural farmland in 2016. The increased number of mosquitoes recorded in 2016 was mainly due to increased temperatures in the study areas, and reflected the change in study sites.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.23-33
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• 2021

The infection status of zoonotic trematode metacercariae (ZTM) was surveyed in freshwater fishes from the water systems of Geum-gang (River) in the Republic of Korea (Korea). A total of 1,161 freshwater fishes from 6 local sites of Geum-gang were examined with the artificial digestion method for 4 years (2012-2015). Clonorchis sinensis metacercariae were detected in 122 (37.2%) out of 328 fishes in the positive fish species from 4 surveyed areas, and their mean intensity was 43 per fish infected. Metagonimus spp. metacercariae were found in 432 (51.7%) out of 835 fishes in the positive fish species from all 6 surveyed areas, and their mean intensity was 30 per fish infected. Centrocestus armatus metacercariae were detected in 285 (75.0%) out of 380 fishes in the positive fish species from 6 surveyed areas, and their mean intensity was 2,100 per fish infected. Echinostoma spp. metacercariae were found in 56 (19.7%) out of 284 fishes in the positive fish species from 5 surveyed areas, and their mean intensity was 10 per fish infected. Clinostomum complanatum metacercariae were detected in 98 (57.3%) out of 171 fishes in the positive fish species from only 2 surveyed areas, and their mean intensity was 11 per fish infected. Conclusively, the endemicity of ZTM is not so high in fishes from water systems of Geum-gang in Korea although it is more or less different by fish species, surveyed areas and ZTM species.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.103-108
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• 2021

To date, there is no report on the genetic diversity of ticks in these regions. A total of 370 representative ticks from the south and east regions of Kazakhstan (SERK) and Xinjiang Uygur Autonomous Region (XUAR) were selected for molecular comparison. A fragment of the mitochondrial cytochrome c oxidase subunit I (cox1) gene, ranging from 631 bp to 889 bp, was used to analyze genetic diversity among these ticks. Phylogenetic analyses indicated 7 tick species including Hyalomma asiaticum, Hyalomma detritum, Hyalomma anatolicum, Dermacentor marginatus, Rhipicephalus sanguineus, Rhipicephalus turanicus and Haemaphysalis erinacei from the SERK clustered together with conspecific ticks from the XUAR. The network diagram of haplotypes showed that i) Hy. asiaticum from Almaty and Kyzylorda Oblasts together with that from Yuli County of XUAR constituted haplogroup H-2, and the lineage from Chimkent City of South Kazakhstan was newly evolved; and ii) the R. turanicus ticks sampled in Israel, Almaty, South Kazakhstan, Usu City, Ulugqat and Baicheng Counties of XUAR were derivated from an old lineage in Alataw City of XUAR. These findings indicate that: i) Hy. asiaticum, R. turanicus and Ha. erinacei shared genetic similarities between the SERK and XUAR; and ii) Hy. marginatum and D. reticulatus show differences in their evolution.

• Parasites, Hosts and Diseases
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• v.59 no.6
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• pp.573-583
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• 2021

Toxoplasma gondii, an intracellular protozoan parasite that infects one-third of the world's population, has been reported to hijack host cell apoptotic machinery and promote either an anti- or proapoptotic program depending on the parasite virulence and load and the host cell type. However, little is known about the regulation of human FHs 74 small intestinal epithelial cell viability in response to T. gondii infection. Here we show that T. gondii RH strain tachyzoite infection or ESP treatment of FHs 74 Int cells induced apoptosis, mitochondrial dysfunction and ER stress in host cells. Pretreatment with 4-PBA inhibited the expression or activation of key molecules involved in ER stress. In addition, both T. gondii and ESP challenge-induced mitochondrial dysfunction and cell death were dramatically suppressed in 4-PBA pretreated cells. Our study indicates that T. gondii infection induced ER stress in FHs 74 Int cells, which induced mitochondrial dysfunction followed by apoptosis. This may constitute a potential molecular mechanism responsible for the foodborne parasitic disease caused by T. gondii.

• IMMUNE NETWORK
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• v.21 no.6
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• pp.42.1-42.20
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• 2021

Eosinophils play critical roles in the maintenance of homeostasis in innate and adaptive immunity. Although primarily known for their roles in parasitic infections and the development of Th2 cell responses, eosinophils also play complex roles in other immune responses ranging from anti-inflammation to defense against viral and bacterial infections. However, the contributions of pattern recognition receptors in general, and NOD-like receptors (NLRs) in particular, to eosinophil involvement in these immune responses remain relatively underappreciated. Our in vivo studies demonstrated that NLRC4 deficient mice had a decreased number of eosinophils and impaired Th2 responses after induction of an allergic airway disease model. Our in vitro data, utilizing human eosinophilic EoL-1 cells, suggested that TLR2 induction markedly induced pro-inflammatory responses and inflammasome forming NLRC4 and NLRP3. Moreover, activation by their specific ligands resulted in caspase-1 cleavage and mature IL-1β secretion. Interestingly, Th2 responses such as secretion of IL-5 and IL-13 decreased after transfection of EoL-1 cells with short interfering RNAs targeting human NLRC4. Specific induction of NLRC4 with PAM3CSK4 and flagellin upregulated the expression of IL-5 receptor and expression of Fc epsilon receptors (FcεR1α, FcεR2). Strikingly, activation of the NLRC4 inflammasome also promoted expression of the costimulatory receptor CD80 as well as expression of immunoregulatory receptors PD-L1 and Siglec-8. Concomitant with NLRC4 upregulation, we found an increase in expression and activation of matrix metalloproteinase (MMP)-9, but not MMP-2. Collectively, our results present new potential roles of NLRC4 in mediating a variety of eosinopilic functions.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.183-194
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• 1990

In an attempt to develop prophylactic and therapeutic measures of the intestinal giant-cystic disease caused by Thelohanellus kitauei in the Israel carp, Cyprinus carpio nodus, pathological observations were conducted upon the carps which were hatched in May 1988 and raised in a net cage fish farm at the Soyang lake, managed by Horim Fisheries for the period of 21 months with 1~2 months interval. After a gross inspection of the carps, necropsy was carried out periodically in order to clarify the pathological changes in various internal organs and muscular tissues. Also. the prevalence of the disease was checked during the period from 1988 to 1990. Gross inspections revealed that the infected carps showed some degree of fading in body and gill color, back-emaciation symptoms, reddish anus accompanying erosion and relaxation and pot-belly, as well as discharge of yellowish white mucoid material from the anus. However, most carps died eventually of intestinal obstruction. Other significant necropsy fadings included cyst formation of various size in the intestinal mucosa, ascites, anemic condition through internal organs and muscular tissues, hyperemia and dilation of intestines with decreased tension, thinness and fragility, and full contents of semi-fluid or yellowish white mucoid material in the intestinal canals. Based on the morphological characteristics of the spores found in the cysts, parasitic location in the intestines, macro- and microscopic findings of the lesions, the parasites were identised as Thelohanellus kitauei Egusa os Nakajima, 1981. Although monthly changes of water temperature were distinct, the extrusion rates of the polar filaments of the spores stayed constant throughout the year with an exception of a lower rate in July, The lesions initiated from mucosa and submucosa in early July became large swellings and then complete mature (orms following the peracute course. From late August the upper cysts were gradually opened and most of the spores were dispersed from anus into the surrounding water through December but only a few lasted until next April. The cysts were completely recovered until next September. Comparing the incidence and prevalence of the disease by year tremendous infection and death rates were checked in the first prevalent year, 1988, but the rates were significantly decreased in the second year, and showed an almost normal status in the third year, 1990. As the above summarized results showed, the disease entity might come to an end in three years after the first prevalent year, however, the spores must be strictly prevented because they could be infective in the water for one year.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.694-704
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• 2016

Various infectious and parasitic diseases are known to be the main factors that cause decline in the global amphibian population. In Korea, commercial frog farms have been running since 2005. However, until now, studies on diseases including studies on parasitic diseases that occur in farm frogs have not been conducted. In this study, we studied and compared the acanthocephalan infection rates and the number of parasites in the body cavity, stomach, and small and large intestines of the Dybowskii's brown frogs collected from inside and outside the frog farms in Inje, Goesan, Gongju and Boryeong. In addition, we classified the acanthocephalan parasites into genera by analyzing their nuclear 18S rRNA genes. On an average, 51.7% of the investigated frogs were infected by acanthocephalans, which belong to the Centrorhynchus genus. The infection rate of the frogs collected in the Inje farm was 15%, significantly lower than those from the Goesan, Gongju and Boryeong farms. The rate in Goesan was 55%, which is lower than Gongju (80%) and Boryeong (90%) although it is not statistically significant. No difference was found in the infection rate and in the number of parasites in male and female frogs and between the groups collected from inside and outside of the farms. The number of infected parasites negatively correlated with the body condition of the frogs. The most parasites were found in the stomach followed by the small and large intestines and the body cavity. This study is the first report on the Centrorhynchus acanthocephalan infection of amphibians in Korea and it suggests the necessity for acanthocephalan parasite management and for conducting further disease-related studies in commercial frog farms.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.248-254
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• 2013

A Gram-negative bacterium was isolated from mushroom media that markedly reduces the level of extracellular toxins (i.e., tolaasins) produced by Pseudomonas tolaasii, the most destructive pathogen of cultivated mushrooms. The HC1 strain was selected as detoxifying tolaasin by bioassay on potato and it was identified Pseudomonas sp. by the cultural, morphological and physiological characteristics, and analysis of the 16S rRNA. The isolated bacterium is saprophytic but not parasitic nor pathogenic to cultivation mushroom. The isolated bacterium for P. tolaasii cell, was sufficient for detoxification in vitro. Inoculation of the isolated bacterium prevents the development of bacterial disease in Pleurotus ostreatus, Flammunia velutipes and Agaricus bisporus. Control efficacy of brown blotch of strain HC1 treatment was 69, 68 and 55% on Agaricus bisporus, Flammulina velutipes and Pleurotus ostreatus, respectively. The suppressive bacterium may be useful in future for the development of biocontrol system and the construction of genetically modified edible fungi resistant to the disease caused by P. tolaasii.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.6825-6830
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• 2015

Opisthorchis viverrini is remains a public health problem in Thailand, particularly in the northeast and north regions which have the highest incidences of chonalgiocarcinoma (CCA). O. viverrini causes the disease opithorchiasis, and its has been classified as a group 1 biological carcinogen. Humans, dogs, and cats become infected with O. viverrini by ingesting raw or undercooked fish containing infective metacercariae. The first human cases of O. viverrini infection were reported in Thailand 100 years ago, and it's still a problem at the community level. Based on data for the year 2009, more than 6 million people were infected with O. viverrini. Associated medical care and loss of wages in Thailand costs about $120 million annually. This review highlights the current status of O. viverrini infection in communities of Thailand through active surveillance for the five years period from 2010 and 2015. A total of 17 community-based surveys were conducted, most in the northeast region. Some 7 surveys demonstrated a high prevalence over 20%, and the highest was 45.7%. Most commonly infection was found in age group of 35 years and older, males, and agricultural workers. Although, the national prevalence may be decreasing but the results show that the O. viverrini infection is still high in communities of the northeast region. Therefore, the focus in populations living in northeast Thailand should be screening of infection and changing their eating behavior.