• Pediatric Infection and Vaccine
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• v.9 no.2
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• pp.182-192
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• 2002

Purpose : This study was performed to characterize the epidemiologic and clinical features of acute adenoviral lower respiratory tract infections(LRTIs). Methods : Virological analysis was done from respiratory specimens obtained from patients with LRTIs hospitalized to other hospitals and referred to the Department of Pediatrics, Seoul National University Children's Hospital(SNUCH) from June 1998 to July 2000. Viral diagnosis was made by isolation of viruses employing HEp-2 cell culture and indirect immunofluorescent staining with monoclonal antibodies. Serotypes of adenoviruses were determined by neutralization test using antiserum for types 1, 2, 3, 4, 5, 6, 7 and 11. Medical records of children admitted to the SNUCH were reviewed retrospectively. Results : Adenovirus was isolated from 118(9.0%) of 1,305 children with LRTIs. Serotypes were 3(39.0%), 7(16.9%), 1(11.0%), 2(7.6%), 4(7.6%), 6(5.9%), 11(2.5%), and 5(0.8%) and 10 strains(8.5%) were not neutralized by antisera included in the study. Infections by type 3 and type 7 occurred in outbreaks. Male to female ratio was 1.0:0.9 and mean age was 1.95 years. The clinical diagnoses were pneumonia(83%), acute tracheobronchitis(12%) and bronchiolitis(5%). Associated symptoms, signs and abnormal laboratory findings included cough(100%), sputum(73.5%), fever(54.2%), rale(59.3%), wheezing(34%), anemia(35%) and leukopenia(15.8%). Mortality was in 13.5%. Residual radiologic sequelae was identified in 32.6% of the patients followed. Conclusion : These data confirms that adenovirus may cause severe lower respiratory tract diseases, and infections by type 3 and 7 may occured in outbreaks.

• 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.

• 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.

• Pediatric Infection and Vaccine
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• v.10 no.1
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• pp.102-113
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• 2003

Purpose : Acute respiratory tract infections are the most common illnesses in children. The great majority of these infections involving lower respiratory tracts infections(LRTI) are caused by respiratory viruses such as respiratory syncytial virus(RSV), parainfluenza virus (PIV), influenza virus(INF), adenovirus(ADV), etc. Our purpose of this study was to examine the seasonal occurrence, clinical and laboratory features of each viral infections. Methods : Nasopharyngeal aspirates(NPA) were collected from 913 hospitalized children on the first day of admission. They were all admitted to Hangang Sacred Heart hospital and diagnosed as LRTIs. The study period was from September 1998 to August 2002. Specimens were inoculated onto HEp-2 cell, LLC-MK2 cell and MDCK cell. Viruses were detected by immunofluorescent method performed at day 10 postinoculation. Respiratory viruses were detected in 251(27%) cases. Medical records of 208 cases diagnosed as acute LRTIs were all taken reviewed and analyzed. Results : The identified pathogens were RSV 122 cases(58%), PIV 30 cases(14%), INFA 20 cases(10%), INFB 21 cases(11%) and ADV 15 cases(7%) during the study period. Outbreaks of RSV infections occurred every year but mostly on December, 1998 and November, 1999. LRTIs by PIV and ADV occurred during all seasons of the year. INFA was isolated moslty on March, 1999 and January, 2000. INFB infections occurred largely on April, 2002. The clinical diagnoses were bronchiolitis 88 cases(43%), pneumonia 87 cases(42%), croup 19 cases(9%) and tracheobronchitis 14 cases(6%). Common symptoms and signs were cough, rhinorrhea, sputum and fever. WBC counts in peripheral blood showed normal findings in 123 cases(59%). Each viral infections also showed some differences in auscultatory findings and chest X-ray findings. Conclusion : We learned that viruses are one of the major and important etiologic agents of acute LRTIs of children in Korea. However, we still need to find out more about its characteristic clinical features and continue studying on their seasonal occurrence to focus on their management and also prevention.

• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.723-730
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• 2005

Purpose : This study was performed to characterize the etiology and clinical features of acute viral lower-respiratory tract infections(LRI). Methods : Etiologic agents and clinical features of acute viral LRI were studied from October. 2003 through March. 2004 in hospitalized children with LRI(253 cases) at Samsung Cheil Hospital. The viruses were identified by indirect immunofluorescent method. Medical records of patients with proven viral LRI were reviewed retrospectively. Results : Ninety two cases(36.4%) were confirmed as viral infections. The identified pathogens were respiratory syncytial virus(RSV, 76.0%), adenovirus(ADV, 12.0%), influenza virus type A(INFA, 9.8 %), influenza virus type B(INFB, 1.1%) and parainfluenza virus(PIV, 1.1%). Eight four point eight% of patients were younger than 2 years of age. Clinical diagnosis of LRI were pneumonia(56.5%), bronchiolitis(35.9%), tracheobronchitis(4.3%) and croup(3.3%). The clinical symptoms and signs were cough(98.8%), rhinorrhea(82.6%), fever(70.7%), rale(67.4%), wheezing(29.3%), chest retraction(28.3%) and cyanosis(4.3%). The severe respiratory symptoms and signs were more common in RSV-infected patients, even cyanosis could be observed. Seventeen point four percent of patient had fever of $38.5^{\circ}C$ or higher and their most common etiologic agent was INFA(66.7%). Twenty three point nine percent had fever more than 5 days and common etiologic agent was INFA(77.8%). The elevated WBC count($>14{\times}10^3/{\mu}L$) was in 14.1%, and common etiologic agents were INFA(22.2%) and ADV(18.2%). C-reactive protein(CRP >4.0 mg/dL) was increased in 13.0%, and common in ADV(63.6 %). Increased aspartate aminotransferase(AST)/alanine aminotransferase(ALT) was detected in 10.9%, and the most common etiologic agent was RSV(12.9%). Conclusion : The common agents of acute viral LRI were RSV, ADV and INF, respectively. Because the etiologic agents present variable clinical features, it may be helpful to treat and to evaluate acute viral LRI that we should understand their etiologic variability.

• 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.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.75-82
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• 2007

Purpose : Human metapneumovirus (hMPV) is a newly identified paramyxovirus that causes a variety of clinical syndromes in children, including upper and lower respiratory tract illnesses. hMPV is considered an ubiquitous virus causing respiratory tract diseases among children especially during late winter and spring seasons. We report clinical features of human metapneumovirus infection in Korean children. Methods : hMPV infection was diagnosed by reverse transcriptase-polymerase chain reaction (RT-PCR) in respiratory specimens obtained from patients with acute respiratory tract infections from October, 2004 to May, 2005. Medical records of all hMPV-positive patients were reviewed, retrospectively. Results : A total of 15 hMPV were identified from 443 nasopharyngeal aspirations by RT-PCR (3.4%). The range of age of the patients with hMPV infection was from 1 month to 62 months (median age, 31.5 months), with similar numbers of females (8/15) and males (7/15). Among hMPV-positive children, 53.3% (8/15) were aged less than 24 months. Fever, cough, rhinorrhea, vomiting, diarrhea, tachypnea, and chest wall retractions were common findings. Most common clinical diagnosis was pneumonia (60%). Two of the 15 hMPV-positive patients were also positive for adenovirus. Fever persisted from 0 to 10 days (mean 4.9 days). The duration of hospitalization ranged from 4 to 7 days (mean 5.6 days). Conclusion : hMPV accounted for a small but significant proportion of respiratory tract infection in infants and children. Future development and application of diagnostic tools will determine the burden of disease caused by this newly discovered pathogen.

• Clinical and Experimental Pediatrics
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• v.52 no.3
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• pp.330-338
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• 2009

Purpose : The causes of acute lower respiratory tract infection (ALRTI) are mostly attributable to viral infection, including respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza virus A/B (IFV A/B), or adenovirus (ADV). Several Korean studies reported human metapneumovirus (hMPV) as a common pathogen of ALRTI. However, studies on seasonal distribution and clinical differences relative to other viruses are insufficient, prompting us to perform this study. Methods : From November 2006 to October 2007, we tested nasopharyngeal aspiration specimens in children hospitalized with ALRTI with the multiplex reverse transcriptase-polymerase chain reaction to identify 6 kinds of common pathogen (hMPV, RSV, PIV, IFV A/B, and ADV). We analyzed positive rates and clinical features by respiratory chart review. Results : We detected 38 (8.4%) hMPV-positive cases out of 193 (41.8%) virus-positive specimens among 462 patients. HMPV infection prevailed from March to June with incidence peaking in April. HMPV-positive patients were aged 15 years (76.3%), and the ratio of boys to girls was 1.2:1. The median age was 27 months. HMPV primarily caused pneumonia (76.3 %) (P=0.018). Average hospitalization of HMPV-associated ALRTI patients was 5.8 days. In addition, they showed parahilar peribronchial infiltration (100%) on chest X-ray, normal white blood cell count (73.7%), and negative C-reactive protein (86.8 %) (P>0.05). All hMPV-positive patients recovered without complication. Conclusion : HMPV is a common pathogen of ALRTI in Korean children, especially in 1-5 year olds, from March to May. Immunocompetent children diagnosed with hMPV-associated ALRTI may have a good prognosis.