• Journal of Life Science
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• v.33 no.8
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• pp.605-611
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• 2023

Recently, sporadic cases of human infection by genetic reassortants of H7Nx influenza A viruses have been reported; such viruses have also been continuously isolated from avian species. In this study, A/wild bird/South Korea/sw-anu/2023, a novel reassortant of the H7N1 avian influenza virus, was analyzed using full-genome sequencing and molecular characterization. Phylogenetic analysis showed that A/wild bird/South Korea/sw-anu/2023 belonged to the Eurasian lineage of H7Nx viruses. The polymerase basic (PB)2, PB1, polymerase acidic (PA), and nucleoprotein (NP) genes of these viruses were found to be closely related to those of avian influenza viruses isolated from wild birds, while the hemagglutinin (HA), neuraminidase (NA), matrix (M), and nonstructural (NS) genes were similar to those of avian influenza viruses isolated from domestic ducks. In addition, A/wild bird/South Korea/sw-anu/2023 also had a high binding preference for avian-specific glycans in the solid-phase direct binding assay. These results suggest the presence of a new generation of H7N1 avian influenza viruses in wild birds and highlight the reassortment of avian influenza viruses found along the East Asian-Australasian flyway. Overall, H7Nx viruses circulate worldwide, and mutated H7N1 avian viruses may infect humans, which emphasizes the requirement for continued surveillance of the H7N1 avian influenza virus in wild birds and poultry.

• Pediatric Infection and Vaccine
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• v.11 no.2
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• pp.158-169
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• 2004

Purpose : Although influenza is one of the most important cause of acute respiratory tract infections in children, virus isolation is not popular and there are only a few clinical studies on influenza and diagnostic methods. We evaluated the epidemiological and clinical features of influenza in children and rapid antigen detection test(QuickVue influenza test) on fist half of the year 2004 in Busan. Methods : From January 2004 to June 2004, throat swab and nasal secretion were obtained and cultured for the isolation of influenza virus and tested by rapid antigen detection test(QuickVue influenza test) in children with suspected influenza infections. The medical records of patients with influenza virus infection were reviewed retrospectively. Results : Influenza viruses were isolated in 79(17.2%) out of 621 patients examined. Influenza virus was isolated mainly from March to April 2004. The ratio of male and female with influenza virus infection was 1.2 : 1 with median age of 4 years 6month. The most common clinical diagnosis of influenza virus infection was bronchitis. There was no difference between influenza A and B infection in clinical diagnosis and symptoms. All patients recovered without severe complication. The sensitivity obtained for rapid antigen detection test (QuickVue influenza test) was 93.6% and the specificity was 80.2%, the positive predictive value 40.8%, the negative predictive value 98.8%. Conclusion : With rapid antigen detection test, it is possible early detection of influenza in children. reduction in use of antimicrobial agent and early use of antiviral agent.

• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.87-93
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• 2016

Purpose: An outbreak of influenza virus is uncommon in neonatal intensive care unit (NICU). The clinical presentation of influenza virus infection in neonates is diverse. This study was aimed to report an outbreak of influenza A in a NICU and to investigate the clinical characteristics of influenza virus infection in neonates especially preterm infants during the 2011-2012 influenza season in Korea. Methods: We reviewed the medical records of 29 patients who were evaluated by respiratory virus multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) at NICU of Kosin University Gospel Hospital during the 2011-2012 seasonal influenza outbreak in Korea. Results: Eleven patients (37.9%) were influenza A virus RT-PCR positive during the survey periods. They were all preterm infants and three of them had no symptoms. Eight patients had symptoms and it was fever (18%, 2/11), respiratory difficulty (72.7%, 8/11) without symptoms of upper respiratory infection, and gastrointestinal symptoms (27.3%, 3/11). The median duration of symptom was 5 days. There were differences of duration of admission at the test of respiratory RT-PCR, Clinical Risk Index for Babies (CRIB) score, use of mechanical ventilation, and use of dexamethasone before infection between influenza A virus RT-PCR positive and negative group. All 11 patients with influenza A were discharged without any complications. Conclusions: The symptoms of influenza A virus infection in the preterm infants is nonspecific. Influenza A virus should be considered as a possible cause of infection in NICU during the influenza season in the community.

• Korean Journal of Poultry Science
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• v.48 no.2
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• pp.81-90
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• 2021

Avian influenza viruses (AIVs) must utilize host cellular factors to complete their life cycle, and fragile X mental retardation protein (FMRP) has been reported to be a host factor promoting AIV ribonucleoprotein (vRNP) assembly and exports vRNP from the nucleus to the cytoplasm. The functional role of chicken FMRP translational regulator 1 (cFMR1) as a host factor of AIV is, however, poorly understood. In this study, we targeted the cFMR1 gene in DF1 cells using clustered regularly interspaced short palindromic repeats/Cas9-mediated genome editing to examine the functional role of cFMR1 as a host factor of AIV. We found that cFMR1 stimulated viral gene transcription during early stages of the viruses' life cycle and did not affect viral progeny production and viral polymerase activity in DF1 cells 24 hours post infection. cFMR1 overexpression did not exert significant effects on virus production, compared to the control. Therefore, unlike in mammalian systems (e.g., humans or mice), cFMR1 did not play a pivotal role in AIV but only seemed to stimulate viral proliferation during early stages of the viral life cycle. These results imply that the interplay between host factors and AIV differs between mammals and avian species, and such differences should be considered when developing anti-viral drugs for birds or establishing AIV-resistant bird models.

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.284-288
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• 2001

Respiratory viruses are one of the most infectious agent in human. Six different respiratory tract viruses were detected from Busan while working on the preventive surveillance in 1997-2000. The isolation rate from suspected specimens were 8.4%. Influenza virus A, B type, parainfluenza virus, adenovirus, mumps virus, and measles virus were examined from throat swabs, serum, and secretions of patients. Influenza A/Sydney/05/97(H3N2)-like, A/Johanesburg/33/94(H3N2)-like, A/Beijing/262/95(H1N1)-like and Influenza B/Beijing/262/95-like, B/Harbin/07/94-like, B/Guangdong/08/93-like were found. Adenovirus serotype 1, 2, 3 and 5 were detected, antibody of mumps both IgM and IgG were shown and outbreaks of measles were confirmed. Different antigenic types of influenza virus were detected every year, one outbreak of parainfluenza in 1999, mumps outbreak in 1999 and 2000, and incidence of measles in 2000 were noticeable. Monthly outbreaks were November through following March with influenza virus, January through June with adenovirus, February through May and December with mumps, April through August and November, December with measles, respectively. The size of isolated viruses were 130 nm with influenza virus B type, non-enveloped, icosahedron with 70 nm with adenovirus, 170 nm with mumps virus and 180 nm with parainfluenza virus in diameter, respectively.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.53-59
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• 2005

Influenza is an important public health problem which occurs almost every winter in temperate climates and is often associated with increased rates of hospitalization and death. In 1999, our influenza surveillance was initiated with 4 voluntary sentinel physicians and the Public Health Center. During the 2003-2004 influenza season, 124 influenza viruses were isolated from 401 clinical specimens, which were collected from patients with Influenza-like illness(ILI) in Seoul. The case definition of ILI is a case with fever more than $38^{\circ}C$ and systemic symptoms; cough, or sore throat. ILI was the highest at the 20-49 age $group(23\%)$ and the rate of virus isolation was the highest at the 7-19 age $group(50\%)$. Among 124 influenza viruses, isolates 83 were identified as A/H3N2 type and others were subtyped as influenza B viruses in 2003-2004 season. Influenza viruses were collected $39.1\%$ at Nowon-Gu, $13.5\%$ Gangnam-Gu and Seocho-Gu etc. and the isolate rate of virus had the area difference; Yongsan-Gu $66.7\%$, Gangnam-gu $50.0\%$, Nowon-Gu $39.9\%$, Kangbuk-Gu $36.8\%$, Seocho-Gu $27.8\%$, Dongjak-Gu $21.2\%$. Out of 401 individuals, 160 was vaccinated $(40\%)$ and the vaccination rate was the highest at the 20-49 age $group(32\%)$. These findings may contribute to the recommondation of the influenza vaccine formulation and the development of influenza control measure.

• Clinical and Experimental Pediatrics
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• v.52 no.7
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• pp.785-790
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• 2009

Purpose : Febrile convulsions are a common pediatric neurological disease, and it is important to prevent such a disease by controlling the risk factors that may recur. A recent report states that influenza virus infections have a high probability of a relationship with febrile convulsions; therefore, it is necessary to identify the clinical properties of febrile convulsions in relation to domestic influenza virus infections. Methods : Between November 2005 and February 2008, children hospitalized because of febrile convulsions and subsequently confirmed to have influenza infections were enrolled as subjects (patient group, n=11). The control subjects were those admitted with influenza virus infections but no febrile convulsions (control group 1, n=46) and those who developed febrile convulsions without influenza virus infection (control group 2, n=53). Results : The patient group showed a higher maximum body temperature ($39.3{\pm}0.5^{\circ}C$), more histories of past febrile convulsions (72.7%), and a shorter total duration of fever ($2.9{\pm}1.2$ days) than control group 1. When multivariate analysis was performed, the probability of febrile convulsions was found to be as high as 225.9 times in patients who had influenza virus infections with a past history of febrile convulsions (OR=225.9, 95% CI: 1.7-4780.0, P<0.05). When patients with febrile convulsions were compared based on the symptoms of influenza virus infections, the patient group showed a shorter duration of fever ($0.9{\pm}0.7$ days) before convulsion than control group 2; these convulsions were mostly a recurrence of febrile convulsions. When multivariate analysis was performed, the cases with a past history of febrile convulsions showed 5.5 times (OR=5.5, 95% CI: 1.2-25.1, P=0.03) the probability of convulsions when infected with the influenza virus, and this probability decreased by 0.3 times over one-day increments of the febrile period until febrile convulsions (95% CI: 0.1-0.9, P=0.02). Maximum body temperature, total duration of fever, family history of febrile convulsions, and complex febrile convulsions did not show a statistical significance. Conclusion : In cases of pediatric influenza virus infection, the past history of febrile convulsions could be identified within the risk factor of recurrent febrile convulsions. Therefore, influenza vaccination of children having a past history of febrile convulsions will be helpful to avoid the recurrence of these convulsions.

• Proceedings of the Korean Society of Life Science Conference
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• 2000.12a
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• pp.20-26
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• 2000

호흡기계 및 소화기계에 감염된 전염성 바이러스에 대한 역학적 기초자료로 이용하고자 1999년 1월부터 12월까지 부산지역에서 분리된 전염성 바이러스의 특징과 계절적 발생추이, 환자의 성별, 연령별 발생에 대해 조사한 결과는 다음과 같다. 1. 1999년도 바이러스 가검물 2261건에서 분리한 호흡기계감염 바이러스 279건과 소화기계 감염 바이러스 83주를 분리하였으며, 이중 인플루엔자 바이러스 A형이 96주(29.6%), B형이 107주(33.0%)로 대부분을 차지하였다. 2. 1999년의 바이러스 분리의 성별 분포는 총 360명의 환자 중 179명(49.7%)의 남성 및 181명(50.3%)의 여성으로 비슷한 양상을 나타내었다. 이중 호흡기계의 경우 279명의 감염환자 중 남성이 130명(46.6%), 여성이 149명(53.4%)으로 여성의 감염율이 비교적 높았으나, 소화기계의 경우 83명의 감염환자 중 남성이 51명(61.4%), 여성이 32명(38.5%)으로 남성의 감염율이 거의 2배정도 높게 나타났다. 3. 1999년의 연령별 분포는 10세 이하의 어린이가 194명(59.9%)으로 대부분을 차지하였으며, 이중 인플루엔자 바이러스가 99명(30.6%)으로 가장 높은 감염을을 나타내었다 유행성이하선염 바이러스의 감염어린이 중에 $l1{\sim}15$세의 연령층이 15명으로(53.3%)로 가장 높게 나타났다. 4. 1999년 월별 감염율은 호흡기계 감염증 바이러스의 경우 1월부터 4월까지, 그리고 12월에 증가 추세를 보이면서 4월에 가장 높은 감염율을 나타내었다 소화기계 감염증 바이러스의 경우 9, 10, 11월을 제외한 모든 월별에 관찰되었으며, echo와 coxsackie 바이러스는 무균성 수막염 환자에서 하절기에 집중적으로 발생하였다. 동절기에 유행하는 설사 바이러스는 12월에 비교적 높은 양상을 나타내었다. 5. 인플루엔자 바이러스는 MDCK 세포에서, 아데노 바이러스와 유행성 이하선염 바이러스는 HEp-2 세포에서, 파라인플루엔자 바이러스는 Vero 세포에서, 그리고 echo, coxsackie B 바이러스와 장내 바이러스는 HEp-2, Vero, BGM 세포에서 뚜렷한 세포병변 효과를 나타내었다. 6. 분리한 바이러스는 전자현미경으로 관찰한 결과 인플루엔자 바이러스 A 형(HINI, H3N2)은 95nm, B 형은 70nm크기의 구형을 나타내었으며, 바이러스표면의 지질 이중층이 뚜렷하게 관찰되었다. 아데노 바이러스는 외피가 관찰되지 않았으며, nucleocapsid는 symmetry이고 크기는 71nm로서 바이러스 입자 표면에 icosaheral capsomer의 배열이 명확하게 관찰되었고, 파라인플루엔자 바이러스와 유행성 이하선염 바이러스는 외피가 있는 구형의 큰 viron으로180, 170nm 크기이었다. 7. Echo와 coxsackie B group 바이러스는 모두 외피가 없는 isometric 형으로 크기는 $30{\sim}45nm$ 이었고, enteric adeno 바이러스는 84nm 크기로서 외피가 없고, 입자 표면에 capsomer의 배열이 명확하게 관찰되었고, rotavirus는 크기가 70nm이며 외층 capsid 단백질과 내층 capsid 단백질이 두층으로 되어 있는 전형적인 수레바퀴 모양을 나타내었다. 이상의 결과로 보아 호흡기계 및 소화기계에 감염되는 전염성 바이러스는 연중 지속적으로 분리되고 있으며 전염성이 강하여 집단 발생은 일으키는 경우도 많고 최근 들어 유행성 이하선염과 흥역 바이러스의 발생률이 높은 추이를 나타내고 있지만 아직은 특이한 바이러스 치료제가 개발되어 있지 않았으므로 지속적인 대책과 아울러 장기적인 발생 가능에 대한 예방책을 흥보하여야 할 것으로 보이며 계속적인 바이러스성 전염병 유행예측조사 및 역학조사가 적극적으로 이루어져야 할 것으로 사료된다.

• Journal of Life Science
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• v.32 no.5
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• pp.375-390
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• 2022

Influenza viruses are zoonotic respiratory pathogens, and influenza infections have caused a substantial burden on public health systems and the livestock industry. Although currently approved seasonal influenza vaccines have shown potent protection efficacy against antigenically well-matched strains, there are considerable unmet needs for the efficient control of viral infections. Enormous efforts have been made to develop broadly protective universal influenza vaccines to tackle the huge levels of genetic diversity and variability of influenza viruses. In addition, antiviral drugs have been considered important interventions for the treatment of viral infections. The viral neuraminidase inhibitor oseltamivir is the most widely used antiviral medication to treat influenza A and influenza B viruses. However, unsatisfactory clinical outcomes resulting from side effects and the emergence of resistant variants have led to greater attention being paid to plants as a natural resource for anti-influenza drugs. In particular, the recent COVID-19 pandemic has underpinned the need for safe and effective antiviral drugs with a broad spectrum of antiviral activity to prevent the rapid spread of viruses among humans. This review outlines the results of the antiviral activities of various natural products isolated from plants against influenza viruses. Special focus is paid to the virucidal effects and the immune-enhancing effects of antiviral natural products, since the products have broad applications as inactivating agents for the preparation of inactivated vaccines and vaccine adjuvants.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.236-239
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• 2016

$Guillain-Barr{\acute{e}}$ syndrome (GBS) is caused by antecedent infectious diseases in approximately two-thirds of cases. GBS is considered an autoimmune response. Among reported preceding infections, influenza virus is relatively rare. Several reports have identified antibodies related to GBS pathogenesis. However, no case report has described the detection of influenza virus in the cerebrospinal fluid (CSF) of a patient with GBS by polymerase chain reaction (PCR). Here we report the case of a 6-year-old girl who was diagnosed with influenza A 1 week prior and was treated with oseltamivir, after which she visited our hospital for headache and bilateral leg weakness that had persisted for 1 day. We diagnosed her with GBS based on physical and neurologic examination findings, CSF analysis, nerve conduction velocity test results, spinal magnetic resonance imaging, and detection of influenza A virus in her CSF by PCR. She was treated with intravenous immunoglobulin and her symptoms slowly improved. This case report suggests that GBS may be caused by influenza virus through penetration of the CSF.