title: Prospective multicenter study of the viral etiology of bronchiolitis in the emergency department.
abstract: OBJECTIVE
  To determine the viral etiology of bronchiolitis and clinical characteristics of children age < 2 years presenting to the emergency department (ED) with bronchiolitis.
  
  
  METHODS
  The authors conducted a 14-center prospective cohort study during 2005-2006 of ED patients age < 2 years with bronchiolitis. The study was conducted in 10 states as part of the Emergency Medicine Network. Researchers collected nasopharyngeal aspirates and conducted structured interviews, medical record reviews, and 2-week follow-up telephone calls. Samples were tested using reverse transcription polymerase chain reaction for respiratory syncytial virus (RSV), rhinovirus (RV), human metapneumovirus (hMPV), and influenza viruses (Flu).
  
  
  RESULTS
  Testing of 277 samples revealed 176 (64%) positive for RSV, 44 (16%) for RV, 26 (9%) for hMPV, 17 (6%) for Flu A, and none for Flu B. When children were categorized as RSV only, RV only, RV and RSV, and all others (hMPV, Flu, no identified virus), children with RV only were more likely to be African American (19, 62, 14, and 40%, respectively; p < 0.001) and have a history of wheezing (23, 52, 21, and 15%, respectively; p = 0.01). In multivariate models, children with RV were more likely to receive corticosteroids (odds ratio [OR] 3.5; 95% confidence interval [CI] = 1.5 to 8.15). The duration of illness may be shorter for children with RV (Days 8, 3, 6, and 8; p = 0.07).
  
  
  CONCLUSIONS
  In this multicenter study, RSV was the most frequent cause of bronchiolitis (64%). RV was present in 16%, and these children have a distinct profile in terms of demographics, medical history, and ED treatment.
authors.affiliation: Department of Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA. jonathan.mansbach@childrens.harvard.edu
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Mansbach
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: McAdam
authors.forename: Sunday
authors.initials: S
authors.lastname: Clark
authors.forename: Paul D
authors.initials: PD
authors.lastname: Hain
authors.forename: Robert G
authors.initials: RG
authors.lastname: Flood
authors.forename: Uchechi
authors.initials: U
authors.lastname: Acholonu
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D001990:Bronchiolitis, Viral / Q000821:virology*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification*; D008297:Male; D029121:Metapneumovirus / Q000302:isolation & purification*; D011446:Prospective Studies; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification*; D012229:Rhinovirus / Q000302:isolation & purification*; D014481:United States