title: The first wheezing episode: respiratory virus etiology, atopic characteristics, and illness severity.
abstract: BACKGROUND
  Susceptibility to early rhinovirus-induced wheezing has been recognized as an important risk factor for childhood asthma, but data on the first wheezing episode are limited. The aim of this selected population study was to investigate virus etiology, atopic characteristics, and illness severity, as well as their interrelation, among first-time wheezing children.
  
  
  METHODS
  We studied 111 first-time wheezing children aged between 3 and 23 months (88/23 in-/outpatients). The investigated factors included atopy, food, perennial and aeroallergen sensitization, eczema, atopic eczema, elevated blood eosinophil count, and parental allergic rhinitis, asthma, and smoking. Nasopharyngeal aspirates were analyzed for adenovirus, coronaviruses, enteroviruses, bocavirus-1 (also serologically confirmed), influenza viruses, metapneumovirus, parainfluenza viruses, rhinovirus, and respiratory syncytial virus using PCR methods.
  
  
  RESULTS
  The mean age of the study patients was 12 months (standard deviation 6.0). Atopic characteristics could be found in 56%, atopic eczema in 16%, and sensitization in 23% of the cases. In all samples (100%), ≥1 viruses were detected as follows: rhinovirus (76%), respiratory syncytial virus (29%), bocavirus (18%, acute infections), and other viruses <10% each. Virus coinfections occurred in 38% of the children. Rhinovirus infection was positively associated with age, blood eosinophil count, eczema, and duration of cough, as well as parental allergic rhinitis and smoking but negatively associated with virus coinfection (all p < 0.05).
  
  
  CONCLUSIONS
  A respiratory virus infection can be detected in all first-time wheezing children. Rhinovirus dominated the findings and was linked to atopic characteristics, prolonged cough, and parental smoking.
authors.affiliation: Department of Pediatrics, Turku University Hospital, Turku, Finland; Department of Virology, University of Turku, Turku, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Turunen
authors.forename: Annamari
authors.initials: A
authors.lastname: Koistinen
authors.forename: Tytti
authors.initials: T
authors.lastname: Vuorinen
authors.forename: Benedict
authors.initials: B
authors.lastname: Arku
authors.forename: Maria
authors.initials: M
authors.lastname: Söderlund-Venermo
authors.forename: Olli
authors.initials: O
authors.lastname: Ruuskanen
authors.forename: Tuomas
authors.initials: T
authors.lastname: Jartti
mesh_terms: D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology; D018450:Disease Progression; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D007958:Leukocyte Count; D008297:Male; D010850:Picornaviridae Infections / Q000150:complications / Q000453:epidemiology* / Q000276:immunology; D016133:Polymerase Chain Reaction; D012135:Respiratory Sounds / Q000209:etiology / Q000276:immunology*; D012229:Rhinovirus / Q000276:immunology*; D012307:Risk Factors
chemical_list: D000485:Allergens
keywords: atopy; bocavirus; bronchiolitis; child; cough; respiratory syncytial virus; rhinovirus; smoking; virus; wheezing