• Clinical and Experimental Pediatrics
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• v.51 no.10
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• pp.1071-1076
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• 2008

Purpose : Respiratory syncytial virus (RSV) is the most frequent cause of lower respiratory infections in infants and young children. Early detection allows quarantining of infected inpatients to prevent nosocomial transmission and to choose a treatment. To achieve rapid reporting, to facilitate prompt antiviral therapy, and to avoid unnecessary use of antibiotics, an easy, rapid diagnostic method for RSV is needed. We evaluated a lateral flow immunochromatography (RSV Respi-Strip test) and EIA (Enzyme immuno assay) compared to RT-PCR. Methods : From April 2007 to March 2008, 112 consecutive respiratory specimens (nasopharyngeal aspirates, throat swabs, tracheal aspirates, sputum) from patients who were suffering from the clinical signs and symptoms of respiratory tract infection were enrolled in Busan. A total of 112 patients were tested with RSV Respi-Strip (Corio-BioConcept, Belgium), EIA, and RT-PCR at the same time. Results : Of the 112 specimens tested, the number of children who showed positive results at RT-PCR and Respi-Strip were 45 and 42, respectively. The Respi-Strip rapid antigen test had a sensitivity of 88% and a specificity of 94%. The positive and negative predictive values were 90% and 92%, respectively. The agreement was 83%. Conclusion : In our study, the rapid antigen test had as much sensitivity as any method for detection of RSV. The test has many advantages such as easy performance, simple interpretation, and rapid results. If the rapid antigen test is widely applied in the clinical setting, the may be useful for diagnostic and epidemiological studies of RSV infection.

• Journal of Microbiology and Biotechnology
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• v.20 no.10
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• pp.1450-1456
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• 2010

Accurate and rapid diagnosis of Pandemic Influenza A/H1N1 2009 virus (H1N1 2009) infection is important for the prevention and control of influenza epidemics and the timely initiation of antiviral treatment. This study was conducted to evaluate the performance of several diagnostic tools for the detection of H1N1 2009. Flocked nasopharyngeal swabs were collected from 254 outpatients of suspected H1N1 2009 during October 2009. This study analyzed the performances of the RealTime Ready Inf A/H1N1 Detection Set (Roche), Influenza A (H1N1) Real-Time Detection Kit (Bionote), Seeplex Influenza A/B OneStep Typing Set [Seeplex Reverse Transcriptase PCR (RT-PCR)], BinaxNow Influenza A & B Test Kit [Binax Rapid Antigen Test (RAT)], and SD BIOLINE Influenza Ag kit (SD RAT). Roche and Bionote real-time RT-PCR showed identical results for the H1N1 2009 hemagglutinin gene. Compared with real-time RT-PCR, the sensitivities and specificities were 83.7% and 100% for Seeplex RT-PCR, 64.5% and 94.7% for Binax RAT, and 69.5% and 100% for SD RAT. The sensitivities of Seeplex RT-PCR, Binax RAT, and SD RAT in patients aged over 21 years were 73.7%, 47.4%, and 57.9%, respectively. The sensitivities of Seeplex RT-PCR, Binax RAT, and SD RAT on the day of initial symptoms were mostly lower (68.8%, 56.3%, and 31.3%, respectively). In conclusion, multiplex RT-PCR and RAT for the detection of H1N1 2009 were significantly less sensitive than real-time RT-PCR. Moreover, a negative RAT may require more sensitive confirmatory assays, because it cannot be ruled out from influenza infection.

• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.661-666
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• 2009

Purpose : To determine the prevalence and clinical features of codetected respiratory etiological agents for acute respiratory infection in hospitalized children. Methods : Nasopharyngeal aspirates were obtained from hospitalized children with acute respiratory infection at Dankook University Hospital from September 2003 through June 2005. Immunofluorescent staining and culture were used for the detection of respiratory viruses (influenza virus [IFV] types A, B; parainfluenza virus [PIV] types 1, 2, 3; respiratory syncytial virus [RSV]; adenovirus [AdV]). Polymerase chain reaction (PCR) assays were used for Mycoplasma pneumoniae (MP) and Chlamydia trachomatis (CT) detection, and PCR and culture were performed for enterovirus detection. Acid-fast staining and culture were performed for tuberculosis detection. The demographic and clinical characteristics were reviewed retrospectively from the patients medical records. Results : Evidence of two or more microbes was found in 28 children: RSV was detected in 14, PIV 3 in 10, AdV in 10, MP in 8, PIV 2 in 8, CT in 4, and PIV 1 in 3. Codetected agents were found as follows: RSV＋PIV 2, 6 patients; AdV＋MP, 4 patients; AdV＋PIV, 3 patients; RSV＋MP, 3 patients; PIV 1＋PIV 3, 3 patients. Distinct peaks of codetected agents were found in epidemics of MP and each respiratory virus. Conclusion : The codetected infectious agents were RSV, PIV, AdV, and MP, with distinct peaks found in epidemics of MP and each respiratory virus. Although advances in diagnostic methods have increased the prevalence of codetection, its clinical significance should be interpreted cautiously.

• Pediatric Infection and Vaccine
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• v.18 no.1
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• pp.61-67
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• 2011

Purpose : This study was performed to investigate the epidemiologic characteristics of human bocavirus (HBoV)-associated lower respiratory tract infections (LRTIs) in children. Methods : Nasopharyngeal aspirate samples were obtained from 658 children who had been hospitalized for LRTIs in Seoul National University (SNU) Children's Hospital and SNU Bundang Hospital from March 2000 to September 2005. Multiplex RT-PCR was performed to detect 11 respiratory viruses including respiratory syncytial virus, adenovirus, rhinovirus, parainfluenza viruses 1 and 3, influenza viruses A and B, human metapneumovirus, HBoV, human coronavirus (HCoV) OC43/ 229E, and HCoV-NL63. Clinical data were reviewed retrospectively. Results : Overall, respiratory viruses were detected in 325 (49.4%) among 658 patients. HBoV was detected in 62 cases (9.4%) and was responsible for 19.1% of virus-positive cases. HBoV was prevalent among infants and young children aged from 3 months to 5 years with the mean age of 25.3 months. Co-detection of HBoV and other respiratory viruses was observed in 37.1% which is significantly higher than average co-detection rate (12.3%) among overall virus-positive cases (P=0.000). HBoV was identified mainly in late spring and early summer from May to July. Conclusion : This study describes epidemiologic features of HBoV in Korean children compared with those associated with other respiratory viruses. HBoV was prevalent among LRTIs in childhood, especially in late spring and early summer season in Korea.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.9-22
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• 1996

Respiratory Syncytial virus (RSV) is an important cause of acute lower respiratory tract infections in human, with infants and young children being particularly susceptible. In the temperate zones, sharp annual outbreaks of RSV occur during the colder months, in both the northern and the southern hemisphere. RSV is unusual in that it can repeatedly reinfect individuals throughout life and infect babies in the presence of maternal antibody. RSV isolates can be divided into two subgroups, A and B, on the basis of their reactions with monoclonal antibodies, and the two subgroups are also distinct at the nucleotide sequence level. The specific diagnosis of RSV infection was best made by isolation of virus in tissue culture, identification of viral antigen, or by specific serologic procedures. Recently, rapid detection of RSV and analysis of RSV strain variation became possible by development of methods of reverse transcription and polymerase chain reaction amplification. In this study, to determine the genetic diversity of RSV found in Korea, 173 bp and 164 bp spanning selected regions of the RSV F and SH genes were enzymatically amplified and sequenced, respectively. Eight for F gene and three for SH gene were detected in 66 nasopharyngeal swap samples tested. Two major antigenic subgroups, A and B were confirmed from Korean samples (seven for subgroup A and one for subgroup B). At the nucleotide level of the F gene region, Korean subgroup A strains showed 95-99% homologies compared to the prototype A2 strain of subgroup A and 93-100% homologies among Korean subgroup A themselves. For the SH gene region, Korean subgroup A strain showed 97.5% homology compared to the prototype A2 strain of subgroup A, and Korean subgroup B strain showed 97% homology compared to the prototype 18537 strain of subgroup B. Most of base changes were transition and occured in codon position 3, which resulted in amino acid conservation. Using the maximum parsimony method, phylogenetic analysis indicated that Korean RSV strains formed a group with other RSV strains isolated from the United States, Canada, the Great Britain and Australia.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.91-96
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• 2007

Purpose : This study was performed to evaluate a new rapid diagnostic kit (BIOLINE $RSV^{TM}$; Standard Diagnostics Inc., Yongin, Korea), a lateral-flow immunoassay, in the detection of respiratory syncytial virus (RSV) from the nasopharyngeal aspirates (NPA) of children with lower respiratory tract infections (LRTIs) in comparison with other diagnostic methods. Methods : Three hundred and nineteen NPAs were selected from a large pool of NPAs that had been obtained from children with LRTIs. All specimens had already been tested for RSV by culture and immunofluorescent (IF) test, and had been kept frozen. Tests with BIOLINE $RSV^{TM}$ were performed at least twice. All who conducted the experiments or interpreted the test results were blinded to the results of both culture and IF tests. Results : One hundred seven (97.3%) of 110 specimens that were positive for RSV by both culture and IF test, 29 (87.9%) of 33 that were positive by IF test only, 20 (76.9%) of 26 that were positive by culture only, and 140 (93.3%) of 150 that were negative by both methods were negative for RSV by BIOLINE $RSV^{TM}$. By combining the above results, the following 5 diagnostic values of BIOLINE $RSV^{TM}$ were determined in comparison with viral culture or IF test; sensitivity, 92.3% (156/169, 95% confidence interval [CI], 87.1-97.5%); specificity, 93.3% (140/150, 95% CI, 88.4-98.2%); positive predictive value, 94.0% (156/166, 95% CI, 89.5-98.5%); negative predictive value, 91.5% (140/143, 95% CI, 86.0-97.0%); and agreement, 95.9% (306/319, 95% CI, 92.1-99.7%), respectively. Conclusion : This study revealed that BIOLINE $RSV^{TM}$ demonstrated good sensitivity and specificity for the detection of RSV antigen from NPAs of children with LRTIs. Because of simple methods and quick results, this test may be useful for the diagnosis of RSV infection during the epidemic periods.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.172-177
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• 2015

Purpose: This study aimed to analyze the epidemic period of RSV infection and evaluate the appropriate time of palivizumab immunoprophylaxis. Methods: From January 1991 to July 2012, nasopharyngeal (NP) aspirates were obtained from patients who visited Seoul National University Children's Hospital for respiratory symptoms. NP samples were used to detect respiratory viruses. Among them, we analyzed the positive number and detection rate of RSV infection in two-week interval. The beginning of RSV season was defined when RSV positive number was more than 4 and RSV detection rate was over 10%. From January 2007 to March 2014, we analyzed the starting time of palivizumab immunoprophylaxis for the infants at high risk. Results: The RSV detection rate was 2,013/21,698 (9.69%) over 22 years. The median RSV season was from $2^{nd}-3^{rd}$ week of October to $1^{st}-2^{nd}$ week of February. The earliest starting week was the 3rd week of July in year 2001, and the latest end week was the 3rd week of May in year 1990. Palivizumab immunoprophylaxis was initiated most frequently at the 3rd week of October (18.7%). However, the percentage of starting palivizumab on the 1st week of September has increased from 3.8% in the year 2007 to 14.1% in 2013. Conclusions: The year to year variability of RSV season exists. The starting time of palivizumab immunoprophylaxis should be adjusted based on the season of RSV epidemic.

• Clinical and Experimental Pediatrics
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• v.48 no.3
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• pp.266-275
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• 2005

Purpose : Acute respiratory tract infections are the most common illnesses in children. The great majority of these infections involving lower respiratory tracts infections(LRTIs) are caused by respiratory viruses such as respiratory syncytial virus(RSV), parainfluenza virus(PIV), influenza virus (Flu), and adenovirus(ADV), etc. Our purpose was to determine seasonal epidemiology and clinical characteristic features of each viral infection. Methods : Nasopharyngeal aspirate(NPA)s were collected from 4,554 hospitalized children diagnosed as LRTIs on the first day of admission. The study period was from September 1998(Autumn) through May 2003(Spring). Respiratory viruses were detected in 881(19 percent) cases by isolation of the virus or by antigen detection method using indirect immunofluorescent staining. We reviewed the medical records of 837 cases retrospectively. Results : The identified pathogens were RSV in 485 cases(55 percent), PIV in 152 cases(17 percent), FluA in 114 cases(13 percent), ADV in 79 cases(9 percent) and FluB in 51 cases(6 percent). Outbreaks of RSV occurred every year, mostly in the November through December period and of PIV in the April through June period. LRTIs by FluA reached the highest level in January, 2002. FluB infection showed an outbreak in April, 2002. The clinical diagnoses of viral LRTIs were bronchiolitis in 395 cases(47 percent), pneumonia in 305 cases(36 percent), croup in 73 cases(9 percent) and tracheobronchitis in 64 cases(8 percent). Conclusion : Viruses are one of the major etiologic agents of acute LRTIs in chidren. Therefore, we must continue to study their seasonal occurrence and clinical features to focus on management, and also for reasons of prevention.

• Clinical and Experimental Pediatrics
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• v.51 no.8
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• pp.834-841
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• 2008

Purpose : This study was perfomed to analyze in detail the viral etiology of acute lower respiratory tract infections (ALRI) in Cheunan, Korea by multiplex RT-PCR, including human rhinovirus (hRV) and newly identified viruses such as human metapneumovirus (hMPV) and human coronavirus (HCoV-OC43, HCoV-229E/NL63). Method : Nasopharyngeal aspirates (NPA) were collected from 863 hospitalized children with ALRI on the first day of admission at Soonchunhyang University Cheonan Hospital and analyzed by multiplex RT-PCR from December 2005 to November 2006. Results : Viral agents were detected from 474 subjects (54.9%). The identified viral pathogens were hRV 9.2%, hMPV 6.8%, HCoV-229E/NL63 1.4%, and HCoV-OC43 2.1%. Coinfections with ${\geq}2$ viruses were observed in 108 patients (22.8%). The major period of viral ALRI was the first year of life. Clinical diagnoses of viral ALRI were pneumonia (59.5%), bronchiolitis (24.7%), tracheobronchitis (11.4%), and croup (4%). The most common causes of bronchiolitis was respiratory syncytial virus B (RSV B), whereas hMPV, hRV, HCoV-229E/NL63, and HCoV-OC43 were commonly found in patients with pneumonia. The number of hMPV infections peaked between March and May 2006. HCoV-OC43 was prevalent from November to February 2006, whereas HCoV-229E and hRV were detected throughout the year. Conclusion : Although the study was confined to one year, hMPV was not detected during winter and peaked between March and April, which was not consistent with previous studies'. This present study indicates that HCoV is a less common respiratory pathogen in cases of ALRI in Korean children