• Korean Journal of Microbiology
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• v.43 no.3
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• pp.173-178
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• 2007

The occurrence of acute respiratory infections caused by the influenza virus are particularly high during the winter season in Busan, Korea. In 2004 and 2005, a study of the rate of occurrences of the influenza virus was conducted. The results reveal that in 2004, of the 1,869 people with an acute respiratory infection that 154 (8.2%) people were infected by the influenza virus. In 2005, of the 1,579 people infected with an acute respiratory infection that 19 people (1.2%) were infected with the influenza virus. The study shows a decrease in the numbers of an influenza virus infection from 2004 to 2005. Data was collected by inspecting throat swabs and nasal discharge from those with an acute respiratory infection. Further inspection of the throat swab and nasal discharge from the infected individuals during 2004 and 2005 study show the occurrence of the different types of influenza virus in the population: 6 cases (3.5%) of influenza type A/H1N1, 129 cases (74.5%) of A/H3N2, and 38 cases (22.0%) of type B. The study conducted in 2004 and 2005 reveal that children between the ages of two and five were more likely to be infected than any other age group. In the study, about 62.2% of the infected individuals were between two and five years old. The detection rates between males and females are similar. However, it is notable that females are slightly more likely to develop an acute respiratory infection caused by the influence virus compared to their male counterparts.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.172-177
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• 2020

Influenza viruses cause respiratory diseases in humans and animals with high morbidity and mortality rates. Conventional anti-influenza drugs are reported to exert side effects and newly emerging viral strains tend to develop resistance to these commonly used agents. Fritillaria thunbergii (FT) is traditionally used as an expectorant for controlling airway inflammatory disorders. Here, we evaluated the therapeutic effects of FT extracts against influenza virus type A (H1N1) infection in vitro, in ovo, and in vivo. In the post-treatment assay, FT extracts showed high CC50 (7,500 ㎍/ml), indicating low toxicity, and exerted moderate antiviral effects compared to oseltamivir (SI 50.6 vs. 222) in vitro. Antiviral activity tests in ovo revealed strong inhibitory effects of both FT extract and oseltamivir against H1N1 replication in embryonated eggs. Notably, at a treatment concentration of 150 mg/kg, only half the group administered oseltamivir survived whereas the FT group showed 100% survival, clearly demonstrating the low toxicity of FT extracts. Consistent with these findings, FT-administered mice showed a higher survival rate with lower body weight reduction relative to the oseltamivir group upon treatment 24 h after viral infection. Our collective results suggest that FT extracts exert antiviral effects against influenza H1N1 virus without inducing toxicity in vitro, in ovo or in vivo, thereby supporting the potential utility of FT extract as a novel candidate therapeutic drug or supplement against influenza.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.449-454
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• 2011

The infection of pandemic influenza viruses such as swine flu (H1N1) and avian flu viruses to the host cells is related to the following two factors: First, the surface protein such as HA (hemagglutinin) and NA (neuraminidase) of the influenza virus. Second, the specific structure of the oligosaccharide [sialic acid(${\alpha}2$-6) galactose(${\beta}1$-4)glucose or sialic acid(${\alpha}2$-3)galactose(${\beta}1$-4)glucose] on the host cell. After recognizing the specific structure of the oligosaccharide on the surface of host cells by the surface protein of the influenza virus, the influenza virus can secrete sialidase and cleave the sialic acid attached on the final position of the specific structure of the oligosaccharide on the surface of host cells. Tamiflu (oseltamivir), known as a remedy of swine flu, has a saccharide analog structure, especially the sialic acid analog. Tamiflu can inhibit the invasion of influenza viruses (swine flu and avian flu viruses) into the host cells by competition with sialic acid on the terminal position of the specific oligosaccharide on the surface of the host cell. Because of the emergence of Tamiflu resistance, the development of new potent anti-influenza inhibitors is needed. The inhibitors with positive-charge groups have potential as antiviral therapeutics, and the strain specificity must also be resolved.

• Biomolecules & Therapeutics
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• v.26 no.3
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• pp.290-297
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• 2018

We aimed to understand the molecular changes in host cells that accompany infection by the seasonal influenza A H1N1 virus because the initial response rapidly changes owing to the fact that the virus has a robust initial propagation phase. Human epithelial alveolar A549 cells were infected and total RNA was extracted at 30 min, 1 h, 2 h, 4 h, 8 h, 24 h, and 48 h post infection (h.p.i.). The differentially expressed host genes were clustered into two distinct sets of genes as the infection progressed over time. The patterns of expression were significantly different at the early stages of infection. One of the responses showed roles similar to those associated with the enrichment gene sets to known 'gp120 pathway in HIV.' This gene set contains genes known to play roles in preventing the progress of apoptosis, which infected cells undergo as a response to viral infection. The other gene set showed enrichment of 'Drug Metabolism Enzymes (DMEs).' The identification of two distinct gene sets indicates that the virus regulates the cell's mechanisms to create a favorable environment for its stable replication and protection of gene metabolites within 8 h.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.243-252
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• 2013

Among the 16 hemagglutinin (HA) subtypes of avian influenza virus (AIV), only the H5 and H7 subtypes have caused highly pathogenic avian influenza (HPAI) in poultry. However, most H5 or H7 subtype viruses are categorized as low pathogenic avian influenza (LPAI). Some AIVs, including the H5 and H7 HPAI viruses, have shown the ability to infect humans directly. In this study, we describe the biological and molecular characterization of an H5N3 AIV (SBD/KR/KNU SYG06/06) isolated from spot-billed duck (Anas poecilorhyncha) in Korea. A phylogenetic analysis of the eight viral genes showed that the SBD/KR/KNU SYG06/06 isolate belongs to the Eurasian lineage and that the SBD/KR/KNU SYG06/06 isolate was clearly different from HPAI H5N1 strains, including human isolates and the Italian HPAI H5N2 strains. Additionally, no relationship was found between SBD/KR/KNU SYG06/06 and the Korean HPAI H5N1 isolates. The SBD/KR/ KNU SYG06/06 isolate had avian specific receptor binding site residues in the HA protein and the four C-terminal amino acids in the NS1 protein. The HA protein of the SBD/KR/KNU SYG06/06 isolate exhibited the typical LPAI motif at the cleavage site and this virus produced no cytopathic effects in MDCK cells without trypsin. Given these results, we suggest that the H5N3 AIV isolated from the spot-billed duck should be considered an LPAI virus and should have no pathogenic effect in humans.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.868-872
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• 2007

H1N2 influenza viruses are circulating in pigs worldwide and cause considerable economic losses to the pig industry. We genetically analyzed the genes of our isolates from Korean pigs, and compared the antigenicity of our isolates with swine H1N2 viruses isolated from pigs in the U.S.A. In addition, we serologically surveyed the infection rate of swine H1N2 viruses in pigs. We found that H1N2 isolates from Korean pigs are genetically more related to swine H1N2 viruses isolated from pigs in the U.S.A. than those in European countries. When antigenicity was compared, our isolates were weakly reacted to antibodies against swine H1N2 viruses isolated from pigs in the U.S.A. The serological surveillance using sera from pigs in Korea showed that about 46% was positive for H1N2 viruses. Our results suggest that swine H1N2 viruses are widespread in Korean pigs, and the development of a vaccine against H1N2 viruses may help to control their infection in pigs.

• Tuberculosis and Respiratory Diseases
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• v.69 no.3
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• pp.207-211
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• 2010

Novel influenza A (H1N1) virus is a common pathogen of febrile respiratory infection recently. Here, we report the case of a 63-year-old male patient who presented with 3 days' ongoing cough and fever. He was diagnosed with novel influenza A (H1N1) pneumonia by real-time reverse-transcriptase-polymerase-chain-reaction (rRT-PCR). During treatment for novel influenza A (H1N1), his symptoms and radiologic findings improved initially, but multiple lung nodules developed subsequently and found on chest x-ray (on the 5th hospital day). Mycobacterium abscessus was isolated repeatedly from sputum and bronchoalveolar lavage fluid. To our knowledge, this is the first reported case of Mycobacterium abscessus lung disease in a patient with H1N1 influenza pneumonia.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.273-279
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• 2007

Swine influenza is an acute, infectious respiratory disease caused by type A influenza viruses in pigs. In the previous studies, serological surveys have indicated the presence of H3N2 swine influenza virus (SIV) since 1995 in Korea. And the percentage of the antibody-positive rate was 39.12% in the survey determining the prevalence of H1N1 SIV antibodies in 2002. The purpose of this study was therefore to investigate the sero-prevalence of SIV regard to the age of the pig and the season between June 2004 and May 2005. In this study, a total of 932 sera were used. These sera were randomly selected from blood samples, which were submitted to Department of Veterinary Pathology, Kangwon National University and Department of Veterinary Virology, Seoul National University from June 2004 to May 2005. These sera have been tested by ELISA test kit (IDEXX Lab, USA) for the SIV H3N2, H1N1 respectively. SAS version 9.1 was used for the statistical analysis based on the age of the pig and the season. The overall sero-prevalence of the antibody against H3N2 SIV was 20.82% (194/932). The overall sero-prevalence of the antibody against H1N1 SIV was 37.23% (347/932). The overall dual sero-prevalence of the antibody against H3N2 and H1N1 SIV was 10.62% (99/932). H3N2 has significant difference in statistically regarding the age of the pig and the season (p<0.0001). H1N1 has significant difference in statistically regarding the age of the pig (p<0.0001) but has not significant difference in statistically regarding the season (p=0.5882).

• Childhood Kidney Diseases
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• v.18 no.1
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• pp.47-50
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• 2014

Infection is the most important cause of death in children with nephrotic syndrome. Influenza viral infections can be fatal for these children, given the annual outbreak of this virus, with the mortality rate being similar to that of respiratory syncytial virus in healthy children. Pneumonia is recognized as the most important complication of influenza infections, as it is associated with high death rates. However, the influenza vaccine, as well as antiviral agents, can be used for prevention and treatment. Therefore, aggressive management with influenza vaccination and antiviral agents will lower the overall mortality rate in children with nephrotic syndrome. Here we report the case of a 7-year-old boy with nephrotic syndrome and influenza A virus (H1N1) pneumonia.

• Journal of Life Science
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• v.11 no.3
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• pp.248-253
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• 2001

The outbreak patterns of the internal and external and external patients in the 20 designated hospitals and in 16 health centers were monitored to investigate and the characteristics of the virus isolates were as follows. Two hundreds and thirteen strains of influenza virus were isolated from the oral specimens of 1,686 patients with respiratory disease in Pusan. 1999. Among these isolates, 203 strains were A-type and the rest were B-type. The outbreak patterns for sex and age group were as follows. The male outbreak was similar to the female outbreak: male outbreak, 45.5% and female outbreak, 54.5%. Most of the patients were less than 10 days old. The monthly influenza outbreak was consistent from Jan. to Dec in 1999. The 96 strains from the A-type isolates were A/Sydney/05/97(H3N2)-like, the 107 strains were A/Beijing/262/95(H1N)-like, and all of the 10 B-type isolates were B/Harbin/07/94-like.