title: Etiology of bronchiolitis in a hospitalized pediatric population: prospective multicenter study.
abstract: BACKGROUND
  In 2006, bronchiolitis due to adenovirus nosocomial infections resulted in the closure of a pediatric department in northern Portugal.
  
  
  OBJECTIVE
  To determine the etiology of bronchiolitis in northern Portugal.
  
  
  METHODS
  It was a prospective multicenter study on the etiology of bronchiolitis during the respiratory syncytial virus (RSV) season (November-April). Children < or = 24 months of age admitted for a first wheezing episode were included. Nasopharyngeal specimens were analyzed by an indirect immunofluorescent-antibody assay (IFA) for RSV, adenovirus (HAdV), parainfluenza (PIV) 1-3 and influenza (IV) A and B and by polymerase chain reaction (PCR) or reverse transcription-PCR for the same viruses and for human metapneumovirus (hMPV), bocavirus (HBoV), rhinovirus (HRV), coronaviruses (229/E; NL63; OC43; HKU1) and enterovirus.
  
  
  RESULTS
  During this period, 253 children were included, 249 IFA analyses and 207 PCRs were performed. IFA detected RSV in 58.1%; PCR increased it to 66.7%. IFA detected HAdV in 3.2%, PCR 10.0%. PCR detected IV A in 5; IV B in 2; PIV 1 in 6, PIV 2 in 4 and PIV 3 in 11 cases. HBoV, as single agent in 2 cases, and HRV were positive in 8 samples and hMPV in 11. With this virus panel, 19.7% remained without etiology.
  
  
  CONCLUSIONS
  The most frequent agent was RSV, followed by HAdV. PCR can be cost-effective and more accurate than IFA, which is crucial for HAdV that may be associated with significant mortality (IFA alone did not detect 2/3 of the cases).
authors.affiliation: Pediatrics Department, Braga Hospital, 4701-965 Braga, Portugal. henedinaantunes@gmail.com
authors.forename: H
authors.initials: H
authors.lastname: Antunes
authors.forename: H
authors.initials: H
authors.lastname: Rodrigues
authors.forename: N
authors.initials: N
authors.lastname: Silva
authors.forename: C
authors.initials: C
authors.lastname: Ferreira
authors.forename: F
authors.initials: F
authors.lastname: Carvalho
authors.forename: H
authors.initials: H
authors.lastname: Ramalho
authors.forename: A
authors.initials: A
authors.lastname: Gonçalves
authors.forename: F
authors.initials: F
authors.lastname: Branca
mesh_terms: D001988:Bronchiolitis / Q000453:epidemiology* / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D005260:Female; D006760:Hospitalization; D006801:Humans; D007118:Immunoassay; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000821:virology; D016133:Polymerase Chain Reaction; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014777:Virus Diseases / Q000453:epidemiology* / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D014780:Viruses / Q000145:classification* / Q000302:isolation & purification*