title: Respiratory viruses and exacerbations of asthma in adults.
abstract: OBJECTIVE
  To study the role of respiratory viruses in exacerbations of asthma in adults.
  
  
  METHODS
  Longitudinal study of 138 adults with asthma.
  
  
  METHODS
  Leicestershire Health Authority.
  
  
  METHODS
  48 men and 90 women 19-46 years of age with a mean duration of wheeze of 19.6 years. 75% received regular treatment with bronchodilators; 89% gave a history of eczema, hay fever, allergic rhinitis, nasal polyps, or allergies; 38% had been admitted to hospital with asthma.
  
  
  METHODS
  Symptomatic colds and asthma exacerbations; objective exacerbations of asthma with > or = 50 l/min reduction in mean peak expiratory flow rate when morning and night time readings on days 1-7 after onset of symptoms were compared with rates during an asymptomatic control period; laboratory confirmed respiratory tract infections.
  
  
  RESULTS
  Colds were reported in 80% (223/280) of episodes with symptoms of wheeze, chest tightness, or breathlessness, and 89% (223/250) of colds were associated with asthma symptoms. 24% of 115 laboratory confirmed non-bacterial infections were associated with reductions in mean peak expiratory flow rate > or = 50 l/min through days 1-7 and 48% had mean decreases > or = 25 l/min. 44% of episodes with mean decreases in flow rate > or = 50 l/min were associated with laboratory confirmed infections. Infections with rhinoviruses, coronaviruses OC43 and 229E, influenza B, respiratory syncytial virus, parainfluenza virus, and chlamydia were all associated with objective evidence of an exacerbation of asthma.
  
  
  CONCLUSIONS
  These findings show that asthma symptoms and reductions in peak flow are often associated with colds and respiratory viruses; respiratory virus infections commonly cause or are associated with exacerbations of asthma in adults.
authors.affiliation: Department of Microbiology, University of Leicester School of Medicine.
authors.forename: K G
authors.initials: KG
authors.lastname: Nicholson
authors.forename: J
authors.initials: J
authors.lastname: Kent
authors.forename: D C
authors.initials: DC
authors.lastname: Ireland
mesh_terms: D000328:Adult; D001249:Asthma / Q000209:etiology* / Q000382:microbiology / Q000503:physiopathology; D001483:Base Sequence; D003139:Common Cold / Q000382:microbiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010366:Peak Expiratory Flow Rate; D012008:Recurrence; D018357:Respiratory Syncytial Virus Infections / Q000382:microbiology / Q000503:physiopathology; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000150:complications* / Q000382:microbiology / Q000503:physiopathology; D012229:Rhinovirus / Q000302:isolation & purification