title: Prevalence and impact of respiratory viral infections in young children with cystic fibrosis: prospective cohort study.
abstract: OBJECTIVE
  We aimed to investigate differences in upper and lower respiratory tract symptoms in relation to respiratory viral infections detected with polymerase chain reaction assays in young children with cystic fibrosis and healthy control subjects.
  
  
  METHODS
  In a 6-month winter period, 20 young children with cystic fibrosis and 18 age-matched, healthy, control subjects were contacted twice per week for detection of symptoms of an acute respiratory illness. If any symptom was present, then a home visit was made for physical examination and collection of nasopharyngeal swabs for viral analysis. In addition, parents were instructed to collect nasopharyngeal swabs every 2 weeks.
  
  
  RESULTS
  Children with cystic fibrosis and healthy control subjects had similar frequencies of acute respiratory illnesses (3.8+/-1.0 and 4.2+/-1.7 episodes, respectively). Although there were no significant differences in upper respiratory tract symptoms, the children with cystic fibrosis had longer periods of lower respiratory tract symptoms (22.4+/-22.2 vs 12.8+/-13.8 days) and a higher mean severity score per episode (2.35+/-0.64 vs 1.92+/-0.46). In addition, similar increases in upper respiratory tract symptom scores were associated with significantly greater increases in lower respiratory tract symptom scores in children with cystic fibrosis. No differences in the seasonal occurrences and distributions of respiratory viruses were observed, with picornaviruses and coronaviruses being the most prevalent.
  
  
  CONCLUSIONS
  Although there were no differences in the seasonal occurrences and distributions of polymerase chain reaction-detected respiratory viruses, acute respiratory illnesses were frequently associated with increased lower respiratory tract morbidity in young children with cystic fibrosis.
authors.affiliation: Cystic Fibrosis Centre and Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Centre Utrecht, PO Box 85090, Office KH 01.419.0, 3508 AB Utrecht, Netherlands. b.vanewijk@umcutrecht.nl
authors.forename: Bart E
authors.initials: BE
authors.lastname: van Ewijk
authors.forename: Marieke M
authors.initials: MM
authors.lastname: van der Zalm
authors.forename: Tom F W
authors.initials: TF
authors.lastname: Wolfs
authors.forename: Andre
authors.initials: A
authors.lastname: Fleer
authors.forename: Jan L L
authors.initials: JL
authors.lastname: Kimpen
authors.forename: Berry
authors.initials: B
authors.lastname: Wilbrink
authors.forename: Cornelis K
authors.initials: CK
authors.lastname: van der Ent
mesh_terms: D000208:Acute Disease; D017677:Age Distribution; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012016:Reference Values; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000503:physiopathology / Q000821:virology*; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D018709:Statistics, Nonparametric