• Journal of fish pathology
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• v.24 no.3
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• pp.237-245
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• 2011

Disease survey was conducted to investigate the cause of high mortality in 23 farms of eel, Anguilla japonica, during the period from 2000 to 2010. Seven kinds of fish pathogens were confirmed in the tested fish, which included: Pseudodactylogyrus sp. (infection rate: 65.5%, 19/29 samples), aquabirnavirus (ABV, 62.5%, 15/24 samples), Edwardsiella sp. (44%, 11/25 samples), anguillid herpesvirus 1 (AngHV1, 16.7%, 2/12 samples), Heterosporis sp. (10.3%, 3/29 samples), Vibrio sp. (8%, 2/25 samples), Trichodina sp. (3.4%, 1/29 samples). The rate of single infection was 44.8% (13/29 samples), while 62.1% (18/29 samples) showed mixed type of infection with 2 to 5 different pathogens. The most predominant mixed infection were Pseudodactylogyrus sp.-Edwardsiella sp. (10.3%, 3/29 samples), Pseudodactylogyrus sp.-ABV (10.3%, 3/29 samples), Edwardsiella sp.-ABV (6.9%, 2/29 samples). Infection by the above infectious parasites, bacteria and virus was confirmed in tested eels of juvenile to adult sizes that were cultured at $25{\sim}30^{\circ}C$ in almost the examined farms.

• Korean Journal Plant Pathology
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• v.1 no.3
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• pp.199-206
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• 1985

Viroids are the smallest. well-characterized infectious agents presently known. and so far viroids have been found only in higher plants. The structures of viroid-molecules are single-stranded, covalently closed circular RNA molecules with a range of 240 to 380 nucleotides according to the various viroids. Viroids are remarkable not only as a new category of pathogen, which cause economically important diseases, but also as an excellent model system for biochemical and biophysical investigations because of their small size, relative stability and their self-replication. Four different patato spindle tuber viroid isolates, which express the different symptoms on the same host plant exchange only 2 to 6 nucleotides in the total number of 359 nucleotides, but now the mechanism of viroid pathogenicity is not explained fully. Viroid-melecules are replicated without any special viroid-associated proteins, and during the process of viroid replication oligomeric viroid-associated RNAs are detected at nuclei of viroid infected leaf tissue. The mechanism of viroid replication can now be illustrated according to a possible explanation of rolling-circle system. Although the rapid progress have been made in elucidation of the biochemical and biophysical properties of PSTV and other viroids, the mechanism of viroid replication and pathogenicity is less known and is still a matter of speculation. When these problems can be sufficiently explained, the viroid molecule could play an important role as an available vector in plant genetic engineering.

• Journal of fish pathology
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• v.22 no.1
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• pp.75-83
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• 2009

Disease surveillance was performed to monitor the prevalence of fish pathogens in wild marine fish caught in coastal offshore water from February to October in 2008. A total of 401 fish samples were collected at set net or fish market at landing port on the coast of Pohang, Geoje, Yeosu and Jeju. In this study, 17 kinds of fish pathogens were isolated from 152 fish samples. The detection rates of parasites, bacteria or viruses were 21.4%, 17.0% and 2.7%, respectively. The detected parasites were Scutica, Trichodina, Cryptocaryon, Dactylogyrus, Microcotyle, Benedenia, Bivagina, Heteraxin, Caligus, Epistylis and nematode. The dominant bacterial pathogens were Vibrio, Streptococcus, Photobacterium and Psuedomonas. Red sea bream iridovirus (RSIV) and lymphocystis disease virus (LDV) were detected in 6 species of fish virus examined in this study. The detection rates of fish pathogens from Scorpaenidae, Monacanthidae, Pleuronectidae, Sparidae and Carangidae investigated over 30 samples were 59.2%, 48.4%, 34.2%, 30.6% and18.2%, respectively.

• Journal of Life Science
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• v.21 no.8
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• pp.1156-1162
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• 2011

Equine coital exanthema caused by equine herpesvirus type 3 (EHV-3) is a venereal disease which seriously drops horse reproduction rates. Here, we isolated EHV-3 from infected horses and investigated their biological characteristics. Initial cytopathic effects such as rounding of cells were detected 48 hours post infection of the virus into RK-13 cells. The infected cells were going to detach from the surface of culture flasks 72 hours post infection. The type of isolated viruses from swabbed samples was EHV-3 by PCR analysis. Glycoprotein G (gG) of isolated EHV-3 has a 99.25 percent similarity rate to that of EHV-3 334/74 control strain. The isolated EHV-3 was named Georo strain. Georo strain consisted of four major proteins including 145 kD, 60 kD, 45 kD and 40 kD, as shown by SDS-PAGE analysis. We hope the newly isolated Georo strain of EHV-3 can be used for studying various aspects of Korean equine coital exanthema.

• Pediatric Infection and Vaccine
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• v.26 no.2
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• pp.118-123
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• 2019

Postinfectious glomerulonephritis (PIGN) is most commonly caused by Streptococcus pyogenes in children, but PIGN associated with other pathogens has been described in the literature. A previously healthy 6-year-old boy was admitted with complaints of cough, fever, and right chest pain. The patient was diagnosed with pneumococcal bacteremia and influenza A virus infection and treated with antibiotics and antiviral agent. During hospitalization, generalized edema, hematuria, proteinuria, and increased blood pressure were observed; therefore, we started administering diuretics. The boy was discharged with gross hematuria, and even microscopic hematuria disappeared 14 weeks after discharge. We report a case of PIGN associated with bacteremic pneumococcal pneumonia and influenza A virus infection in children. A urine test and blood pressure measurement should be considered for the early detection of PIGN in children with pneumococcal or influenza A virus infection when they present with nephritic symptoms.

• Journal of Life Science
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• v.30 no.3
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• pp.221-229
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• 2020

Distylium racemosum is an evergreen tree growing wild on Jeju Island, which has been reported to exert biological activity. Obesity is induced by genetic, metabolic, environmental, and other factors. Among these, certain bacterial and viral infections have been shown to cause obesity, which is known as infectobesity. Human adenovirus (HAdV)-36 is one of the viruses that are known to cause infectobesity in humans. Unlike extensive research on preventing obesity and developing anti-obesity drugs, little research has been conducted specifically on the prevention and treatment of infectobesity. Therefore, this study aimed to evaluate the effects of phytochemicals from D. racemosum on the replication of HAdV-36. A549 cells infected with HAdV-36 were treated with an ethyl acetate fraction of a D. racemosum leaf extract (DRE), and the virus titer was calculated based on the hemagglutination (HA) titer. The results showed a concentration-dependent inhibitory effect of DRE treatment on HA titers. DRE treatment was also found to inhibit the cytopathic effects of the virus and the expression of viral genes. Quercitrin was identified as the constituent of DRE exerting an inhibitory effect on HAdV-36 replication. This study shows that DRE can be used as a candidate substance for the development of treatment for HAdV-36 infections. In addition, this study provides a basis to further investigate DRE for the development of anti-infectobesity medication.

• Pediatric Infection and Vaccine
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• v.13 no.2
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• pp.147-155
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• 2006

Purpose : The purpose of this study is to evaluate epidemiological data of pathogens obtained from stool exams and compare them with the clinical course in pediatric patients with symptoms of acute gastroenteritis. Methods : Subjects were selected from patients presenting with symptoms of acute gastroenteritis who visited the outpatient clinic or who were admitted to the Dankook University Hospital from December of 2004 to December of 2005. Stool exams for 17 pathogens was performed. RT-PCR was used to detect norovirus and enzyme-linked immunoabsorbant assay (ELISA) was used to detect rotavirus, adenovirus and astrovirus in the subjects stool samples. Ten different species of bacteria(Salmonella spp., Shigella spp., Clostridium perfrigens, Campylobacter spp., Escherichia coli, Vibrio spp., Staphylococcus aureus, Bacillus cereus, Yersinia spp., and L. monocytogenes) were each selectively cultivated and enzyme immunoassays(EIA) was used to test for antigens for C. parvum, E. histolytica and G. lamblia. Retrospective chart review was performed for comparisons of clinical manifestations. Results : A total of 215 subjects was selected and of these 89 cases(41.4%) showed positive results for at least one pathogen. Male to female ratio was 1.3:1. Age distribution showed 4 cases less than one month(4.5%), 4 cases from 1~2 months(4.5%), 24 cases from 3~12 months(26.7%), 47 cases form 13~48 months(52.8%), 10 cases greater than 48 months (21.2%). Viruses showed the greatest proportion of cases with 68 subjects(77.5%), of these rotavirus being the most commonly reported in 50 cases. Bacteria was identified in 26 cases (29.2%), of these nontyphoidal salmonella was noted in 10 cases. Protozoa followed with 21 cases(23.6%), of these C. parvum was noted in 11 cases and G. lamblia was noted in 10 cases. Mixed infections with more than two pathogens were seen in 22 cases(24.7%), of these viral infection with accompanying parasitic infection was seen in 12(54.5%) cases. Conclusion : In this study we examined various pathogens known to cause acute gastroenteritis in children. Further studies for various pathogens can provide useful information for management of the acute gastroenteritis.

• Journal of fish pathology
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• v.19 no.3
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• pp.215-225
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• 2006

Viral and bacterial pathogens of the wild marine fishes were monitored in 176 wild fish and 15 wild shrimp from 13 and 1 species, respectively, which were captured by a trawl net in the southern sea of Korea during June 2006. Viral pathogens that are common etiologically agents to cultured fish in Korea were not isolated. One and 5 bacterial strains were affiliated to the genus Proteus and Pseudomonas, respectively, but these bacteria do not seem to be associated with mortality of aquacultural fish. An extended monitoring on wild marine fishes were necessary for identification of agents responsible for the cultured fish infections.

• Pediatric Infection and Vaccine
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• v.21 no.1
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• pp.22-28
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• 2014

Purpose: This study aimed at determining the detection rate of respiratory viruses and at investigating the risk factors associated with respiratory virus detection in young infants. Methods: From September 2011 to August 2012, nasopharyngeal swabs were obtained from 227 infants aged ${\leq}90$ days with suspected infectious diseases, including sepsis. We performed a retrospective analysis of their clinical characteristics. The prevalence of respiratory viruses in their nasopharyngeal swabs was assayed by real-time polymerase chain reaction (real-time PCR). Results: In total, 157 (69.2%) infants had more than one of the following respiratory viruses: respiratory syncytial virus (n=75), rhinovirus (n=42), influenza virus (n=18), parainfluenza virus (n=15), human metapneumovirus (n=9), coronavirus (n=9), adenovirus (n=4), and bocavirus (n=3). During the same period, bacterial infections were confirmed in 24 infants (10.6%). The detection of respiratory viruses was significantly associated with the presence of cough, a family history of respiratory illness, and a seasonal preference (fall/winter). Using logistic regression analysis, these 3 variables were also identified as significant risk factors. During fall and winter, detection of respiratory viruses was significantly higher in infants who did not have a bacterial infection. Conclusion: Respiratory virus is an important pathogen in young infants admitted to a hospital, who are suspected with infectious diseases. Detection of respiratory viruses in young infants was associated with seasonality (fall/winter), presence of respiratory symptoms and a family history of respiratory illness.

• Pediatric Infection and Vaccine
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• v.19 no.2
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• pp.71-78
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• 2012

Purpose: Human bocavirus (hBoV), a recently discovered virus, has been detected in children with respiratory tract infections worldwide. The aim of this study was to analyze the frequency and molecular phylogeny of hBoV in the respiratory samples of children with acute respiratory tract infections in 2010. Methods: Nasopharyngeal samples were collected from 953 children with lower respiratory tract infections at Severance children's hospital in Korea from January 2010 to December 2010. We applied the multiplex PCR technique for the identification of 12 respiratory viruses from the samples. Among the total specimens, hBoV positive samples were subjected to phylogenetic analysis by sequencing a fragment of the VP1/VP2 gene junction. Results: hBoV was detected in 141 (14.8%) among 953 patients. The 61.7% of hBoV-positive samples were found to co-exist with other respiratory viruses. The results of phylogenetic analysis showed that all 141 hBoV-positive isolates were identified as hBoV 1, revealing a high similarity among the isolates (>98%). Conclusion: hBoV 1 with minimal sequence variations circulated in children with acute respiratory infections during 2010. More research is needed to determine the clinical severity and outcomes of the minimal sequence variations.