title: Viral etiology of acute lower respiratory tract infections in hospitalized young children in Northern Taiwan.
abstract: BACKGROUND
  Lower respiratory tract infections (LRTIs) comprise a great proportion of diagnoses among hospitalized children. This study identifies the viral pathogens causing LRTIs in young children and compares their clinical features and disease severity.
  
  
  METHODS
  Children younger than 36 months old, hospitalized at a medical center in Northern Taiwan with acute bronchiolitis or pneumonia from April to December 2007, were prospectively enrolled. Nasopharyngeal aspiration fluid samples were sent for virus culture, for direct immunofluorescence test of respiratory syncytial virus (RSV), for rapid influenza viral identification, and for polymerase chain reaction of human metapneumovirus (hMPV), human boca virus (hBoV), and human corona virus. The clinical features and laboratory findings were recorded and analyzed.
  
  
  RESULTS
  A total of 48 children were enrolled. RSV was the most common pathogen (41.7%), followed by hMPV (27.1%), hBoV, and enterovirus (both 6.3%). There were no significant differences in clinical presentation and disease severity between the RSV and hMPV groups. However, the hMPV group had a higher mixed infection rate (p = 0.038). Fourteen children had no identifiable viruses. Children with single, dual, and triple pathogens numbered 26, 7, and 1, respectively. The mixed infection rate reached 23.5% among 34 children with identifiable viruses. Children with a higher severity score had greater chance to develop asthma in the next 2 years (p = 0.042).
  
  
  CONCLUSIONS
  RSV is the most common pathogen causing LRTIs in young children, followed by hMPV. The hMPV group had higher mixed infection rate than RSV group. hBoV does circulate in northern Taiwan.
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Chi-Chun
authors.initials: CC
authors.lastname: Sung
authors.forename: Hsin
authors.initials: H
authors.lastname: Chi
authors.forename: Nan-Chang
authors.initials: NC
authors.lastname: Chiu
authors.forename: Daniel Tsung-Ning
authors.initials: DT
authors.lastname: Huang
authors.forename: Li-Chuan
authors.initials: LC
authors.lastname: Weng
authors.forename: Nai-Yu
authors.initials: NY
authors.lastname: Wang
authors.forename: Fu-Yuan
authors.initials: FY
authors.lastname: Huang
mesh_terms: D000208:Acute Disease; D001988:Bronchiolitis / Q000821:virology*; D002675:Child, Preschool; D017934:Coronavirus / Q000302:isolation & purification; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D006760:Hospitalization; D056661:Human bocavirus / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D029121:Metapneumovirus / Q000302:isolation & purification; D009975:Orthomyxoviridae / Q000302:isolation & purification; D011014:Pneumonia / Q000821:virology*; D016133:Polymerase Chain Reaction; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D013624:Taiwan