• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.1024-1028
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• 2003

Influenza-associated encephalopathy is regarded as one of the major neurologic disease entities along with those of Reye syndrome, acute necrotizing encephalopathy, and myelitis which are known to be related to influenza virus, mostly type A. And it is being actively researched in Japan as it has caused a tremendous increase in the number of deaths from 1997 to 2002, but it has not been yet reported in the Korean pediatric medical community. It attacks those previously healthy children, who have not been vaccinated. Patients start with such symptoms as fever and common respiratory problems, but within 24 to 48 hours they suffer from seizures with acute mental deterioration, become worse, and suffer multiple organ failures including marked elevated transaminase levels as well as coagulopathy. It induces deaths in a couple of days after the symptoms appear or remains a serious neurologic sequelae. Confirmative diagnosis is used to demonstrate influenza viral infection. We report here a 37 month aged boy who was admitted to our hospital during the last influenza season under the diagnosis of influenza associated encephalopathy on the basis of serologic testing by hemagglutinin inhibition(HI). This is the first report confirmed by increased antibody titer of the influenza A virus in Korea.

• Tuberculosis and Respiratory Diseases
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• v.79 no.2
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• pp.70-73
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• 2016

In late March of 2009, an outbreak of influenza in Mexico, was eventually identified as H1N1 influenza A. In June 2009, the World Health Organization raised a pandemic alert to the highest level. More than 214 countries have reported confirmed cases of pandemic H1N1 influenza A. In Korea, the first case of pandemic influenza A/H1N1 infection was reported on May 2, 2009. Between May 2009 and August 2010, 750,000 cases of pandemic influenza A/H1N1 were confirmed by laboratory test. The H1N1-related death toll was estimated to reach 252 individuals. Almost one billion cases of influenza occurs globally every year, resulting in 300,000 to 500,000 deaths. Influenza vaccination induces virus-neutralizing antibodies, mainly against hemagglutinin, which provide protection from invading virus. New quadrivalent inactivated influenza vaccine generates similar immune responses against the three influenza strains contained in two types of trivalent vaccines and superior responses against the additional B strain.

• Journal of Microbiology
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• v.43 no.4
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• pp.366-369
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• 2005

Avian influenza viruses playa crucial role i,n the creation of human pandemic viruses. In this study, we have demonstrated that both human and avian influenza receptors exist in cells in the respiratory and intestinal tracts of chickens. We have also determined that primarily cultured chicken lung cells can support the replication of both avian and human influenza viruses.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.750-758
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• 2018

Influenza virus infection is a zoonosis that has great socioeconomic effects worldwide. Influenza infection induces respiratory symptoms, while the influenza virus can infect brain and leave central nervous system sequelae. As children are more vulnerable to infection, they are at risk of long-term neurological effects once their brains are infected. We previously demonstrated that functional changes in hippocampal neurons were observed in mice recovered from neonatal influenza infection. In this study, we investigated changes in myelination properties that could affect neural dysfunction. Mice were infected with the influenza virus on postnatal day 5. Tissues were harvested from recovered mice 21-days post-infection. The expression levels for myelin basic protein (MBP) were determined, and immunohistochemical staining and transmission electron microscopy were performed. Real-time polymerase chain reaction and Western blot analyses showed that mRNA and protein expressions increased in the hippocampus and cerebellum of recovered mice. Increased MBP-staining signal was observed in the recovered mouse brain. By calculating the relative thickness of myelin sheath in relation to nerve fiber diameter (G-ratio) from electron photomicrographs, an increased G-ratio was observed in both the hippocampus and cerebellum of recovered mice. Influenza infection in oligodendrocyte-enriched primary brain cell cultures showed that proinflammatory cytokines may induce MBP upregulation. These results suggested that increased MBP expression could be a compensatory change related to hypomyelination, which may underlie neural dysfunction in recovered mice. In summary, the present results demonstrate that influenza infection during the neonatal period affects myelination and further induces functional changes in influenza-recovered mouse brain.

• IMMUNE NETWORK
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• v.20 no.4
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• pp.31.1-31.14
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• 2020

The effectiveness of current influenza vaccines is considered suboptimal, and 1 way to improve the vaccines is using adjuvants. However, the current pool of adjuvants used in influenza vaccination is limited due to safety concerns. Aloe vera, or aloe, has been shown to have immunomodulatory functions and to be safe for oral intake. In this study, we explored the potential of orally administered processed Aloe vera gel (PAG) as an adjuvant for influenza vaccines in C57BL/6 mice. We first evaluated its adjuvanticity with a split-type pandemic H1N1 (pH1N1) Ag by subjecting the mice to lethal homologous influenza challenge. Oral PAG administration with the pH1N1 Ag increased survival rates in mice to levels similar to those of alum and MF59, which are currently used as adjuvants in influenza vaccine formulations. Similarly, oral PAG administration improved the survival of mice immunized with a commercial trivalent influenza vaccine against lethal homologous and heterologous virus challenge. PAG also increased hemagglutination inhibition and virus neutralization Ab titers against homologous and heterologous influenza strains following immunization with the split-type pH1N1 Ag or the commercial trivalent vaccine. Therefore, this study demonstrates that PAG may potentially be used as an adjuvant for influenza vaccines.

• Korean Journal of Veterinary Service
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• v.40 no.3
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• pp.187-192
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• 2017

In this report, fifteen monoclonal antibodies (MAbs) against an avian influenza virus (H9N2 subtype) were newly produced and characterized. These MAbs proved to react to the epitopes of nucleocapsid protein (NP), hemagglutinin (HA), neuraminidase (NA) and non-structural protein 1 (NS1) of Korean H9N2 strain, respectively. Two HA-specific MAbs showed the ability to inhibit the hemagglutination activity of H9N2 subtype avian influenza virus when tested by hemagglutination inhibition (HI) assay. All MAbs did not cross-react with other avian-origin viruses (Newcastle disease virus, infectious bursal disease virus, infectious bronchitis virus and avian rotavirus) by immunofluorescence test or enzyme-linked immunosorbent assay. The MAbs produced in this study could be useful as the materials for diagnostics and therapeutics against Korean-lineage H9N2 virus infections.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.699-707
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• 2012

Since the 2009 pandemic human H1N1 influenza A virus emerged in April 2009, novel reassortant strains have been identified throughout the world. This paper describes the detection and isolation of reassortant strains associated with human pandemic influenza H1N1 and swine influenza H1N2 (SIV) viruses in swine populations in South Korea. Two influenza H1N2 reassortants were detected, and subtyped by PCR. The strains were isolated using Madin-Darby canine kidney (MDCK) cells, and genetically characterized by phylogenetic analysis for genetic diversity. They consisted of human, avian, and swine virus genes that were originated from the 2009 pandemic H1N1 virus and a neuraminidase (NA) gene from H1N2 SIV previously isolated in North America. This identification of reassortment events in swine farms raises concern that reassortant strains may continuously circulate within swine populations, calling for the further study and surveillance of pandemic H1N1 among swine.

• Clinical and Experimental Pediatrics
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• v.56 no.4
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• pp.165-175
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• 2013

Purpose: There was a global increase in the prevalence of oseltamivir-resistant influenza viruses during the 2007-2008 influenza season. This study was conducted to investigate the occurrence and characteristics of oseltamivir-resistant influenza viruses during the 2007-2008 and 2008-2009 influenza seasons among patients who were treated with oseltamivir (group A) and those that did not receive oseltamivir (group B). Methods: A prospective study was conducted on 321 pediatric patients who were hospitalized because of influenza during the 2007-2008 and 2008-2009 influenza seasons. Drug resistance tests were conducted on influenza viruses isolated from 91 patients. Results: There was no significant difference between the clinical characteristics of groups A and B during both seasons. Influenza A/H1N1, isolated from both groups A and B during the 2007-2008 and 2008-2009 periods, was not resistant to zanamivir. However, phenotypic analysis of the virus revealed a high oseltamivir $IC_{50}$ range and that H275Y substitution of the neuraminidase (NA) gene and partial variation of the hemagglutinin (HA) gene did not affect its antigenicity to the HA vaccine even though group A had a shorter hospitalization duration and fewer lower respiratory tract complications than group B. In addition, there was no significant difference in the clinical manifestations between oseltamivir-susceptible and oseltamivir-resistant strains of influenza A/H1N1. Conclusion: Establishment of guidelines to efficiently treat influenza with oseltamivir, a commonly used drug for treating influenza in Korean pediatric patients, and a treatment strategy with a new therapeutic agent is required.

• Korean Journal of Veterinary Service
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• v.34 no.3
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• pp.195-200
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• 2011

Swine influenza is an acute respiratory disease prevalent in pig-growing areas all around the world and plays the roles of an intermediate host to be transmitted to mammals including human beings through a genetic recombination with the avian influenza virus. Recognizing that people could be contracted with swine influenza, this study set out to investigate the seroprevalence of individual and multiple infections with two subtypes (H1N1 and H3N2) of the swine influenza virus in pig farms in the Gyeongnam region according to age, area, and season, as well as to provide basic data for the prevention and control of swine influenza. Used in the study were total 904 swine sera that were not vaccinated against the influenza gathered from the pig farms in the Gyeongnam region from November, 2009 to October, 2010. HerdChek SIV (H1N1, H3N2) ELISA kit (IDEXX Laboratories, USA) was used for antibody testing against swine influenza. The test results show that 370 sera (40.9%) were infected with either H1N1 or H3N2 with 37.3% (337 sera) being contracted with H1N1, 13.1% (118 sera) with H3N2, and 9.4% (85) with both H1N1 and H3N2.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1165-1169
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• 2012

In April 2009, the H1N1 pandemic influenza virus emerged as a novel influenza virus. The aim of this study was to compare the performances of several molecular assays, including conventional reverse transcription polymerase chain reaction (RT-PCR), two real-time reverse transcription (rRT)-PCRs, and two multiplex RTPCRs. A total of 381 clinical specimens were collected from patients (223 men and 158 women), and both the Seeplex RV7 assay and rRT-PCR were ordered on different specimens within one week after collection. The concordance rate for the two methods was 87% (332/381), and the discrepancy rate was 13% (49/381). The positive rates for the molecular assays studied included 93.1% for the multiplex Seeplex RV7 assay, 93.1% for conventional reverse transcription (cRT)-PCR, 89.7% for the multiplex Seeplex Flu ACE Subtyping assay, 82.8% for protocol B rRT-PCR, and 58.6% for protocol A rRT-PCR. Our results showed that the multiplex Seeplex assays and the cRT-PCR yielded higher detection rates than rRT-PCRs for detecting the influenza A (H1N1) virus. Although the multiplex Seeplex assays had the advantage of simultaneous detection of several viruses, they were time-consuming and troublesome. Our results show that, although rRT-PCR had the advantage, the detection rates of the molecular assays varied depending upon the source of the influenza A (H1N1)v virus. Our findings also suggest that rRT-PCR sometimes detected virus in extremely low abundance and thus required validation of analytical performance and clinical correlation.