• Pediatric Infection and Vaccine
• /
• v.21 no.1
• /
• pp.22-28
• /
• 2014

Purpose: This study aimed at determining the detection rate of respiratory viruses and at investigating the risk factors associated with respiratory virus detection in young infants. Methods: From September 2011 to August 2012, nasopharyngeal swabs were obtained from 227 infants aged ${\leq}90$ days with suspected infectious diseases, including sepsis. We performed a retrospective analysis of their clinical characteristics. The prevalence of respiratory viruses in their nasopharyngeal swabs was assayed by real-time polymerase chain reaction (real-time PCR). Results: In total, 157 (69.2%) infants had more than one of the following respiratory viruses: respiratory syncytial virus (n=75), rhinovirus (n=42), influenza virus (n=18), parainfluenza virus (n=15), human metapneumovirus (n=9), coronavirus (n=9), adenovirus (n=4), and bocavirus (n=3). During the same period, bacterial infections were confirmed in 24 infants (10.6%). The detection of respiratory viruses was significantly associated with the presence of cough, a family history of respiratory illness, and a seasonal preference (fall/winter). Using logistic regression analysis, these 3 variables were also identified as significant risk factors. During fall and winter, detection of respiratory viruses was significantly higher in infants who did not have a bacterial infection. Conclusion: Respiratory virus is an important pathogen in young infants admitted to a hospital, who are suspected with infectious diseases. Detection of respiratory viruses in young infants was associated with seasonality (fall/winter), presence of respiratory symptoms and a family history of respiratory illness.

• Tuberculosis and Respiratory Diseases
• /
• v.51 no.3
• /
• pp.211-223
• /
• 2001

Background : Rhinovirus infection of the airways results in increased permeability of the airway vascular endothelium with the influx of plasma proteins, including lipids such as LDL. In vitro studies on the effect of oxLDL on leukocytes has shown many pro inflammatory effects on multiple leukocytes. We hypothesized that oxLDL is one mechanism for recruiting granulocytes to the airways during a RV infection. Therefore, chemotaxis and transendothelial migration, in response to nLDL, was determined for these granulocytes. Methods : nLDL was oxidized with 5mM Cu2S04 for 20-24 hours. 3-5 105 cells were loaded into the Transwell filter while the chemotatic agonists were placed in the lower well for chemotaxis. Confluent monolayers on HPMEC were grown on Transwell filters for transendothelial migration. The filters were washed and eosinophils and neutrophils loaded on to the filter with the chemotatic agonist was were placed in the lower well. The wells were incubated for 3 hours. The number of migrating cells was counted on a hemocytometer. Results : OxLDL, but not nLDL, is chemotatic for eosinophils and neutrophils. The level of granulocytes chemotaxis was dependent on both the concentration of LDL and its degree of oxidation. OxLDL stimulates eosinophil and neutrophils migration across HPMEC monolayers (+/-IL-$1{\beta}$ preactivation) in a dose dependent manner. Conclusion : Increased vascular permeability during a RV infection may lead to the influx and oxidation of LDL. The resulting oxLDL. is one possible mechanism for the recruitment of neutrophils and eosinophils to the airway interstitial matrix. Once in the airways, granulocytes can further interact with oxLDL to promote airway inflammation.

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

• Tuberculosis and Respiratory Diseases
• /
• v.80 no.4
• /
• pp.358-367
• /
• 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
• /
• v.53 no.3
• /
• pp.373-379
• /
• 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.

• Pediatric Infection and Vaccine
• /
• v.28 no.2
• /
• pp.101-109
• /
• 2021

Purpose: Common human coronaviruses (HCoVs) are relatively understudied due to the mild nature of HCoV infection. Given the lack of local epidemiology data on common HCoVs, we aimed to describe clinical and epidemiological characteristics of common HCoVs in children. Methods: Respiratory viral test results from 9,589 respiratory samples from Seoul National University Children's Hospital were analyzed from January 2015 to December 2019. Viral detection was done by the multiplex reverse transcription polymerase chain reaction. Demographics and clinical diagnosis were collected for previously healthy children tested positive for HCoVs. Results: Of the 9,589 samples tested, 1 or more respiratory viruses were detected from 5,017 (52.3%) samples and 463 (4.8%) samples were positive for HCoVs (OC43 2.8%, NL63 1.4%, 229E 0.7%). All 3 types co-circulated during winter months (November to February) with some variation by type. HCoV-OC43 was the most prevalent every winter season. HCoV-NL63 showed alternate peaks in late winter (January to March) and early winter (November to February). HCoV-229E had smaller peaks every other winter. Forty-one percent of HCoV-positive samples were co-detected with additional viruses; human rhinovirus 13.2%, respiratory syncytial virus 13.0%, influenza virus 4.3%. Common clinical diagnosis was upper respiratory tract infection (60.0%) followed by pneumonia (14.8%), croup (8.1%), and bronchiolitis (6.7%). Croup accounted for 17.0% of HCoV-NL63-positive children. Conclusions: This study described clinical and epidemiological characteristics of common HCoVs (OC43, NL63, 229E) in children. Continuing surveillance, perhaps by adding HKU1 in the diagnostic panel can further elucidate the spectrum of common HCoV infections in children.