title: The role of respiratory viruses in cystic fibrosis.
abstract: BACKGROUND
  Previous studies have suggested a role played by respiratory viruses in the exacerbation of cystic fibrosis (CF). However, the impact of respiratory viruses could have been underestimated because of the low detection rate by conventional laboratory methods.
  
  
  METHODS
  Children with CF had nasal swabs and sputum samples obtained on a routine basis and when they developed respiratory exacerbations. Nucleic Acid Sequence Based Amplification (NASBA) was used to detect respiratory viruses from nasal swabs. The definition of a respiratory exacerbation was when the symptom score totalled to 4 or more, or if the peak expiratory flow fell by more than 50 l/min from the child's usual best value, or if the parent subjectively felt that the child was developing a cold.
  
  
  RESULTS
  71 patients had 165 reported episodes of respiratory exacerbations. 138 exacerbation samples were obtained of which 63 (46%) were positive for respiratory viruses. In contrast, 23 of 136 asymptomatic nasal swabs (16.9%) were positive for respiratory viruses. There was significantly more viruses being detected during respiratory exacerbations, in particular influenza A, influenza B and rhinovirus (p<0.05). Upper respiratory symptoms significantly correlated with positive respiratory viral detection (p<0.05). This study also showed that viral respiratory exacerbations in CF could be independent from bacterial infections.
  
  
  CONCLUSIONS
  Respiratory viruses are associated with exacerbations in CF and upper respiratory symptoms are strong predictors for their presence. 'Real-time' NASBA has a rapid turn-around time and has the potential to aid clinical decision making, such as the use of anti-virals and administration of antibiotics.
authors.affiliation: Department of Cystic Fibrosis, University Hospital of Wales, Cardiff, UK. Electronic address: denniswat118@hotmail.com.
authors.forename: Dennis
authors.initials: D
authors.lastname: Wat
authors.affiliation: Llandough Hospital, Penarth, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Gelder
authors.affiliation: University of Wales College of Medicine, Cardiff, UK.
authors.forename: Sam
authors.initials: S
authors.lastname: Hibbitts
authors.affiliation: Papworth Hospital, Cambridge, UK.
authors.forename: Fay
authors.initials: F
authors.lastname: Cafferty
authors.affiliation: Royal Gwent Hospital, Newport, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Bowler
authors.affiliation: Neville Hall Hospital, Abergavenney, UK.
authors.forename: Marcus
authors.initials: M
authors.lastname: Pierrepoint
authors.affiliation: Singleton Hospital, Swansea, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Evans
authors.affiliation: Department of Cystic Fibrosis, University Hospital of Wales, Cardiff, UK.
authors.forename: Iolo
authors.initials: I
authors.lastname: Doull
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000821:virology*; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D021141:Nucleic Acid Amplification Techniques; D011024:Pneumonia, Viral / Q000150:complications* / Q000175:diagnosis; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000150:complications / Q000175:diagnosis / Q000821:virology*; D012229:Rhinovirus / Q000302:isolation & purification