title: Respiratory viruses in laryngeal croup of young children.
abstract: OBJECTIVE
  To determine the viral cause of laryngeal croup by use of highly sensitive methods, and including recently recognized viruses in the analysis.
  
  
  METHODS
  One hundred forty-four consecutive children with hoarse voice and inspiratory stridor attending the emergency department were enrolled. Age- and season-matched children presenting with a wheezing illness served as control subjects (n = 76). Nasopharyngeal swabs were analyzed by polymerase chain reaction for rhinovirus and enterovirus, coronavirus, respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza A and B virus, human bocavirus, human metapneumovirus, adenovirus, and Mycoplasma pneumoniae.
  
  
  RESULTS
  Virus infection was documented in 80% of patients with croup and 71% of control subjects. Children with croup had significantly more positive test results for PIV 1 and 2 (31% vs 4% and 6% vs 0%, respectively) and significantly fewer positive test results for RSV (15% vs 28%) than wheezing children. Rhinoviruses and enteroviruses were present equally in both groups (21% vs 25%). There was no significant difference in the frequency of influenza A virus or human bocavirus. Few subjects with adenovirus or M. pneumoniae were detected.
  
  
  CONCLUSIONS
  Acute laryngeal croup is most often associated with PIV, RSV, rhinovirus, and enterovirus. Rhinovirus and enterovirus appeared equally often in croup and in wheezing illness. During late fall, they were found in 39% and 40%, respectively, of the tested samples.
authors.affiliation: Department of Otorhinolaryngology, Head & Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland. heikki.rihkanen@hus.fi
authors.forename: Heikki
authors.initials: H
authors.lastname: Rihkanen
authors.forename: Esa
authors.initials: E
authors.lastname: Rönkkö
authors.forename: Tea
authors.initials: T
authors.lastname: Nieminen
authors.forename: Kaija-Leena
authors.initials: KL
authors.lastname: Komsi
authors.forename: Riitta
authors.initials: R
authors.lastname: Räty
authors.forename: Harri
authors.initials: H
authors.lastname: Saxen
authors.forename: Thedi
authors.initials: T
authors.lastname: Ziegler
authors.forename: Merja
authors.initials: M
authors.lastname: Roivainen
authors.forename: Maria
authors.initials: M
authors.lastname: Söderlund-Venermo
authors.forename: Anne Lahtinen
authors.initials: AL
authors.lastname: Beng
authors.forename: Lahtinen
authors.initials: L
authors.lastname: Anne
authors.forename: Tapani
authors.initials: T
authors.lastname: Hovi
authors.forename: Anne
authors.initials: A
authors.lastname: Pitkäranta
mesh_terms: D016022:Case-Control Studies; D002675:Child, Preschool; D015331:Cohort Studies; D003440:Croup / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000821:virology*; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000378:metabolism*; D012141:Respiratory Tract Infections / Q000821:virology*; D019562:Viral Load
chemical_list: D012367:RNA, Viral