• 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.

• Journal of Life Science
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• v.27 no.3
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• pp.275-282
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• 2017

Adenovirus (ADV) and human bocavirus (hBoV) cause acute respiratory tract infections, and are often associated with increased rates of hospitalization and death, particularly in infants and young children. The aim of this study was to analyze the clinical features and molecular phylogeny of ADV and hBoV isolated in Busan, from January 2011 to November 2013. In total, 3,230 specimens (throat swabs) were collected from patients with influenza-like illnesses and acute respiratory tract infections. Multiplex real-time RT-PCR was performed to detect eight respiratory viru [rhinovirus, adenovirus, respiratory syncytial virus, human coronavirus, human metapneumovirus, human bocavirus, parainfluenza virus and influenza virus] and detected 1,485(46.0%) cases. Among 1,485 positive specimens, 257(8.0%) cases were ADV and 68(2.1%) cases of hBoV. A significant clinical feature of ADV is fever and headache whereas hBoV is wheezing. Serotypic distributions of isolated ADV and hBoV were analyzed by sequencing of hexon and VP1/VP2 gene, respectively. ADV was identified seven different serotypes(1~6, 8), revealing a high similarity among the isolates (>97%). The predominant types of ADV were type 1 in 2011, type 3 and 4 in 2012, type 3 in 2013, respectively. ADV type 3 was major causative type during outbreaks in 2013. All of the hBoV was identified as hBoV type 1.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.235-247
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• 2019

Serological monitoring has been conducted worldwide for early diagnosis of disease and monitoring of immune status in poultry. This study was conducted to evaluate the immune status of layers with sera submitted to the Avian Disease Laboratory, Chungbuk National University from 2015 to 2017. The test results were analyzed by the time submitted and by the age of the chicks. Low pathogenic avian influenza (LPAI) showed a low positive rate of antibody compared with those of Newcastle disease, indicating that domestic vaccination against LPAI was not sufficient. The antibody profile of infectious bronchitis (IB) depicted high level of titer and a low tendency of CV as compared to the uninfected control flocks, which indicated that most layer farms have been exposed to the field IB virus. In case of avian metapneumovirus infection (aMPV) and Mycoplasma synoviae (MS), since the introduction of the vaccine in 2011 and 2017, respectively, the positive rate and the titer level were higher than those in pevious times. No significant difference in the changes of seasonal result was observed, indicating proper vaccination and improvement in biosecurity and management.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.49-55
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• 2010

Purpose : The Purposes of this study are to identify the circulating etiologic viruses of acute lower respiratory tract infection in children and to understand the relation with clinical diagnosis. Methods : We obtained a total of 418 nasopharyngeal aspirates from children admitted for their acute lower respiratory tract infections at three tertiary hospitals in Seoul from September 2008 to March 2009. We performed multiplex RT-PCR to identify 14 etiologic viruses and analyzed their emerging patterns and clinical features. Results : Average age of patients was 16.4 months old and the ratio of male to female was 1.36. Viruses were detected in 56.2% of a total of 418 samples. Respiratory syncytial virus (35%) was the most frequently detected and followed by human rhinovirus (22%), human bocavirus, adenovirus, human metapneumovirus, parainfluenza virus, influenza virus and human coronavirus. Co-infection reached 21.9 % of positive patients. Conclusion : When we manage the patients with acute lower respiratory infectious diseases, we should remind the role of various viral pathogens, which might be circulating by seasons and by local areas.

• Tuberculosis and Respiratory Diseases
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• v.80 no.4
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• pp.358-367
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• 2017

Background: Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Methods: Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. Results: A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ${\geq}16years$, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. Conclusion: The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia.

• Clinical and Experimental Pediatrics
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• v.52 no.11
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• pp.1241-1248
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• 2009

Purpose:The etiology of Kawasaki disease (KD) is still unknown. Recently, an association between human coronavirus NL63 (HCoV-NL63) and KD was implicated. Hence, we attempted to determine the association between KD and acute respiratory viral infections. Methods:Nasopharyngeal aspirate samples were obtained from 54 patients diagnosed with KD at the Seoul National University (SNU) Children's Hospital and SNU-Bundang Hospital between October 2003 and September 2006. Viral diagnoses of 11 respiratory viruses were made using multiplex reverse transcriptase-polymerase chain reaction (RT-PCR): respiratory syncytial virus (RSV), adenovirus, rhinovirus (RV), parainfluenza viruses (PIVs) 1 and 3, influenza viruses (IFVs) A and B, human metapneumovirus (HMPV), human bocavirus (HBoV), HCoV OC43/229E, and HCoV-NL63. Clinical data were reviewed retrospectively. Results:The median age was 32 months (6 months-10.4 years). Respiratory symptoms were observed in 37 patients (69%). The following respiratory viruses were identified in 12 patients (22%): RV (n=4), PIV-3 (n=2), HBoV (n=2), and adenovirus, RSV, PIV-1, IFV-A, and HCoV-NL63 (n=1). Co-infection with PIV-3 and RV was observed in one patient. Respiratory symptoms were observed in 7 (58.3%) and 30 (71.4%) patients of the virus-positive and virus-negative groups (P>0.05). Response rate to intravenous immunoglobulin administration was 67% (n=8) and 86% (n=36) in the virus- positive and virus-negative groups (P>0.05). Conclusion:Respiratory symptoms were commonly observed in KD patients but the association between respiratory viruses and KD were not found. Large multicenter-based investigations are required to confirm the association between acute respiratory viral infections and KD.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.69-74
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• 2007

Purpose : Human coronanviruses (hCovs) including hCoV-229E and hCoV-OC43 have been known as etiologic agents of the common colds and were regarded as clinically insignificant agents. However, recent identification of hCoV-NL63 and hCoV-HKU1 in children with lower respiratory tract infections has evoked the clinical concerns about their prevalence and the clinical significance of these hCoVs in children. This study was performed to investigate the prevalence of hCoVs in children with community-acquired pneumonia. Methods : From March 2006 to January 2007, nasopharyngeal specimens collected from children hospitalized with pneumonia, were tested for the presence of common respiratory viruses (respiratory syncytial virus, influenza A, influenza B, parainfluenza viruses, and adenovirus) using multiplex reverse transcriptase polymerase chain reaction (RT-PCR). Human metapneumovirus (hMPV) infection was excluded by nested RT-PCR using primers for the F-gene. To detect the different strains of hCoVs, nested RT-PCR assays specific for hCoVNL63, hCoV-OC43, hCoV-229E, and hCoV-HKU1 were performed. Results : Out of the 217 nasopharyngeal aspirate from children aged under 15 years, respiratory syncytial virus (RSV) was detected in 32 patients, hMPV in 18, human parainfluenza virus in 10, influenza virus A in 2, and adenovirus in 6. HCoVs were detected by RT-PCR in 8 (3.7%) of the 217 patients, hCoV-229E in 1, hCoV-NL63 in 3, and hCoVOC43 in 4 patients. HCoV-HKU1 was not detected in this study population. Conclusion : Recently identified hCoV-NL63 and hCoV-HKU1 seemed to have a little clinical significance in Korean children with severe or hospitalized community-acquired pneumonia.

• Korean Journal of Poultry Science
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• v.37 no.4
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• pp.361-372
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• 2010

Serological evaluation for the poultry is important for various reasons, such as designing and assessing the vaccination program and diagnosing diseases and for this reason, serologic tests for the layer flocks have been conducted on a regular basis. Moreover, the nationwide serological survey and analysis are essential to understand the epidemiological status of national poultry industry. In this sense, the study was conducted to evaluate the immune status of the layer flocks with the sera submitted to Avian Disease Laboratory, Chungbuk National University in 2009, and several important viral diseases were selected for evaluation including low pathogenic avian influenza (LPAI), Newcastle disease (ND), infectious bronchitis (IB) and avian metapneumovirus (aMPV). For LPAI and ND, the age-related patterns of geometric mean titer (GMT) changes were similar but there were differences in the flock positive rate and the level of GMT due to the different vaccination policy. In the case of IB, the values of GMT showed that the field infection was more prevalent than expected. For aMPV, positive birds in a flock increased as the layers got older, which reflected the course of field infection because vaccination against aMPV was not allowed in 2009. From this study, the immune status for the main viral diseases in layers became more clarified but this information was limited because of only one year study. Therefore, serological survey needs to be conducted on a yearly basis and furthermore include broilers and breeders for a better understanding of the health status in the national poultry industry.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.373-379
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• 2010

Purpose : This study was performed to investigate the epidemiologic and clinical features of 13 respiratory viruses in children with acute lower respiratory tract infections (ALRIs). Methods : Nasopharyngeal aspirates were prospectively obtained from 325 children aged 15 years or less from May 2008 to April 2009 and were tested for the presence of 13 respiratory viruses by multiplex real-time-polymerase chain reaction (RT-PCR). Results : Viruses were identified in 270 children (83.1%). Co-infections with ${\geq}2$ viruses were observed in 71 patients (26.3 %). Respiratory syncytial virus (RSV) was the most common virus detected (33.2%), followed by human rhinovirus (hRV) (19.1%), influenza virus (Flu A) (16.9%), human metapneumovirus (hMPV) (15.4%), parainfluenza viruses (PIVs) (8.3%), human bocavirus (hBoV) (8.0%), adenovirus (ADV) (5.8%), and human coronavirus (hCoV) (2.2%). Clinical diagnoses of viral ALRIs were bronchiolitis (37.5%), pneumonia (34.5%), asthma exacerbation (20.9%), and croup (7.1%). Clinical diagnoses of viral bronchiolitis and pneumonia were frequently demonstrated in patients who tested positive for RSV, hRV, hMPV, or Flu A. Flu A and hRV were most commonly identified in children older than 3 years and were the 2 leading causes of asthma exacerbation. hRV C was detected in 14 (4.3%) children, who were significantly older than those infected with hRV A ($mean{\pm}SD$, $4.1{\pm}3.5$ years vs. $1.7{\pm}2.3$ years; P =0.009). hBoV was usually detected in young children ($2.3{\pm}3.4$ years) with bronchiolitis and pneumonia. Conclusion : This study described the features of ALRI associated with 13 respiratory viruses in Korean children. Additional investigations are required to define the roles of newly identified viruses in children with ALRIs.