• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.2963-2966
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• 2013

Infection with Opisthorchis viverrini (OV) due to eating certain traditional freshwater fish dishes is the principal risk factor for cholangiocarcinoma in Northeast Thailand where the infection is endemic and the incidence of this form of primary liver cancer has been the highest in the world. This paper is the second report of a prospective research project to monitor the impacts of a national liver fluke control programme in a rural community of Northeast Thailand. A sample of 684 villagers aged 20-65 years completed an interview questionnaire and were tested for infection using the Kato thick smear technique. The questionnaire was designed for the exploration of associations between OV infection, previous treatment with praziquantel, and knowledge and beliefs about the drug. The data were analysed using descriptive statistics and multiple logistic regression. The overall prevalence of OV infection was 37.2% and was highest in the 20-35 year age group, in those with a university degree and in those employed in the government sector. As many as 91.8% reported eating fish dishes known to place them at risk of infection. In the multiple regression analysis, previous use of praziquantel and lack of knowledge about whether or not the drug has a protective effect against re-infection were the only factors related to OV infection ($OR_{adj}$= 2.31, 95%CI =1.40-3.79 and $OR_{adj}$= 1.95, 95%CI= 1.24-3.05). The findings were discussed in terms of the possibly unwise dependency on praziquantel as a primary element in a control programme.

• Journal of fish pathology
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• v.9 no.1
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• pp.79-85
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• 1996

The effect of $\beta$-glucan administration on the resistance of Korean catfish(Silurus asotus) to experimental Edwardsiella ictaluri and Aeromonas hydrophila infection was evaluated. Fish were either intraperitoneally received $\beta$-glucan($200\sim1000{\mu}g$/100g body weight) dissolved in physiological saline once or twice at an intervals of 3 days, or placed in $\beta$-glucan bath($100{\mu}g/m\ell$) prepared with filtered tap water for 30 or 60 min. Bacterial challenge was performed by intraperitoneal injection of 0.1 ml of bacteria suspension($2{\times}10^7 CFU/m\ell$) 3 days after $\beta$-glucan administration. The $\beta$-glucan injected fish showed an significantly enhanced resistance against experimental infections. The resistance was much higher in the twice-injected fish than in the once-injected fish. But glucan bath did not affect survival rate after the challenge. The protective effect in the $\beta$-glucan injected fish was higher to A. hydrophila than to E. ictaluri. These results indicate that $\beta$-glucan injection can increase the resistance of Korean catfish against experimental E. ictaluri and A. hydrophila infection and that twice injection of $\beta$-glucan at an 3 day-intervals is more effective to the resistance.

• Journal of fish pathology
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• v.26 no.1
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• pp.19-30
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• 2013

Megalocytivirus is a major fish pathogen in marine aquaculture of Asian countries including Korea. Despite of many species affected by this pathogen, little is known interaction between megalocytivirus and the fish immune system. One of the cyclooxygenase isoforms, named COX-2, is playing an important role in immune regulation, and distinct from COX-1 isoform of constitutive activity. COX-2 enzyme is induced by various inflammatory signals, including injection of lipopolysaccharide or infection by pathogenic agents. We cloned COX-2 gene in rock bream using degenerated primers designed from reported sequences of other fish species in PCR followed with 5'- and 3'-end RACE-PCR. The full length of cDNA of rbCOX2 (rock bream COX-2) gene are 2655 bp and that translates into 609 amino acids. The rbCOX-2 genomic organization are found to span 10 exons separated by 9 introns. We also studied if the experimental infection of rock bream with megalocytivirus could affect the expression of COX-2 gene. When injected with LPS, expression of the COX-2 gene was reached peak level at 1 day post injection and showed 13.10 fold increased level compared with that of control. While, when injected with megalocytivirus, we were not able to find significantly increased COX-2 gene expression different from that of control. Cloned and analyzed COX-2 gene in rock bream will help to understand defence mechanisms in fish after viral infection and will also support the development of the measures for treatment and prevention of viral infection.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.725-730
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• 2015

We observed yellow catfish Pelteobagrus fulvidraco fingerlings cultured in land ponds in Korea swimming in a corkscrew spiral pattern while hanging head-up and tail-down at the water surface, before eventually dying. Externally, these fish displayed “hole in the head” disease, pale gills, and hemorrhages in the base of the pectoral and caudal fins; internally they had liver hemorrhages and kidney discoloration. The bacterium Edwardsiella ictaluri (YCK-01 and YCL-01) was identified in the kidneys and livers of diseased fish via phenotypic characteristics and PCR analysis using the ictaluri-specific primers IVS (an intervening sequence) and IRS (the inter-ribosomal spacer). Infectivity challenges by intraperitoneal and immersion routes showed that a representative bacterial strain (YCK) exhibited strong virulence to yellow catfish, with an LD₅₀ of 3.2×10⁴ CFU/fish and 2.5×10⁶ CFU/mL, respectively. This is the first report of E. ictaluri infection in yellow catfish from Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.1-7
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• 1968

Formerly T. Nishimura, T. Oshima and M. Otsuru studied on Anisakis-like larvae in the various marine fishes from the Japan Sea and the Pacific Ocean. In the present observation, many kinds of marine fishes from the Yellow Sea and the southern coast of Korea were. studied, with the samples from the islands: Eocheng-do, Sohuksan-do, Chuja-do and Keomun-do. The authors examined 313 samples from the adjacent waters of Korea and the distribution of the Anisakis-like larvae in the fish body was found to be 9,219 larvae of Anisakis-like larvae found in the mesentery and coelomic cavity of all samples. Of them, 8,112 Anisakis-like larvae were found from 187 samples from the southern coast of Korea, 1,107 Anisakis-like larvae were found in 126 samples from the Yellow sea (Tables 1 & 2). The fish from the southern coast of Korea are much more infected than the fish from. the Yellow Sea. The larger the fish length, the heavier infection of Anisakis-like larvae were observed.

• Journal of fish pathology
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• v.35 no.2
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• pp.141-155
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• 2022

Rock bream iridovirus (RBIV) causes high mortality and economic losses in the rock bream (Oplegnathus fasciatus) aquaculture industry in Korea. Viral open reading frames (ORFs) expression profiling at different RBIV infection stages was investigated using microarray approaches. Rock bream were exposed to the virus and held for 7 days at 23 ℃ before the water temperature was reduced to 17 ℃. Herein, 28% mortality was observed from 24 to 35 days post infection (dpi), after which no mortality was observed until 70 dpi (end of the experiment). A total of 27 ORFs were significantly up- or down-regulated after RBIV infection. In RBIV-infected rock bream, four viral genes were expressed after 2 dpi. Most RBIV ORFs (26 genes, 96.2%) were significantly elevated between 7 and 20 dpi. Among them, 12 ORF (44.4%) transcripts reached their peak expression intensity at 15 dpi, and 14 ORFs (51.8%) were at peak expression intensity at 20 dpi. Expression levels began to decrease after 25 dpi, and 92.6% of ORFs (25 genes) were expressed below 1-fold at 70 dpi. From the microarray data, in addition to the viral infection, viral gene expression profiles were categorized into three infection stages, namely, early (2 dpi), middle (7 to 20 dpi), and recovery (25 and 70 dpi). RBIV ORFs 009R, 023R, 032L, 049L, and 056L were remarkably expressed during RBIV infection. Furthermore, six ORFs (001L, 013R, 052L, 053L, 058L, and 061L) were significantly expressed only at 20 dpi. To verify the cDNA microarray data, we performed quantitative real-time PCR, and the results were similar to that of the microarray. Our results provide novel observations on broader RBIV gene expression at different stages of infection and the development of control strategies against RBIV infection.

• Journal of fish pathology
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• v.7 no.2
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• pp.105-112
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• 1994

A new bacterial infection occurred among the cultured Korean catfish, Silurus asotus, in Chunbuk prefecture, Korea, 1993. This disease produced about 30% mortality in the fish for 4 months. The diseased fish was swimming listless at the water surface with head up and tail down, sometimes spinnig in circles. The most outstanding clinical sign was ulceration on the skull and at the base of the pectoral fins. The causative organism was isolated from the brain, kidney, spleen and liver of diseased fish, and identified as Edwardsiella icaluri by the biochemical and biophysical characteristics. After intraperitoneal innoculaton of the isolate, the pathogenicity was proved positive for Korean catfish, S. asotus, and channel catfish, Ictalurus punctatus, but negative for carp, Cyprinus carpio.

• Journal of fish pathology
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• v.30 no.2
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• pp.97-105
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• 2017

Parasitic leeches could directly (through causing poor growth, anemia and wound in the fish) and indirectly (by predisposition of the fish to secondary bacterial and fungal infections) affects their hosts. In the present study, fishes that were attacked by leeches in natural and experimental environment were studied. Pathologic samples were obtained from damages at the site of leech bite, as well as kidney and liver of the fish. Histopathological examination revealed numerous lesions at the site of leech bite including tissue demolition, detachment at the site of leech bite in the epidermis of epithelial tissue in the skin, destructed nucleus in epithelial cells of the skin plus necrosis in the damaged skin and weak inflammatory penetration to acute necrotic damages along with piercing dermis layer. Pathologic lesions in the kidney included some changes such as proliferation by increasing glomerular cells and membrane cells in capillary vein of the kidney, blood cell necrosis in kidney with infiltration of white blood cells mainly mononuclear and less polymorphonuclear which are the symptoms of anemia due to blood feeding and sucking by leeches. There was also a chronic kidney infection probably originated from another part of body such as skin. Moreover, leeches caused hemorrhagic anemia due to blood consumption of the hosts, which led to observation of immature red blood cells. Also results showed that diseases induced by leeched in fish could be acute or chronic, which depends on size of fish, species of leech and severity of infection.

• Korean Journal of Bronchoesophagology
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• v.14 no.1
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• pp.42-45
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• 2008

Tracheal injury associated with esophageal injury due to fish bone is very rare. Also, treatment of mediastinitis due to esophageal perforation when it is diagnosed late remains controversial. We report the case that we have successfully experienced treatment of mediastinitis due to tracheal and esophageal injury by fish bone.

• Parasites, Hosts and Diseases
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• v.41 no.2
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• pp.117-120
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• 2003

A human Echinostoma hortense infection was diagnosed by gastroduodenoscopy. An 81-year-old Korean male, living in Yeongcheon-shi, Gyeongsangbuk-do and with epigastric discomfort of several days duration, was subjected to upper gastrointestinal endoscopy. He was in the habit of eating fresh water fish. Two live worms were found in the duodenal bulb area and were removed using an endoscopic forcep. Based on their morphological characteristics, the worms were identified as E. hortense. The patient was treated with praziquantel 10 mg/kg as a single dose. The source of the infection in this case remains unclear, but the fresh water fish consumed, including the loach, may have been the source. This is the second case of E. hortense infection diagnosed by endoscopy in Korea.