title: The September epidemic of asthma exacerbations in children: a search for etiology.
abstract: BACKGROUND
  Predictable peaks of asthma exacerbation requiring hospital treatment, of greatest magnitude in children and of uncertain etiology, occur globally after school returns.
  
  
  OBJECTIVE
  We wished to determine whether asthmatic children requiring emergency department treatment for exacerbations after school return in September were more likely to have respiratory viruses present and less likely to have prescriptions for control medications than children with equally severe asthma not requiring emergent treatment.
  
  
  METHODS
  Rates of viral detection and characteristics of asthma management in 57 (of 60) children age 5 to 15 years presenting to emergency departments with asthma in 2 communities in Canada between September 10 and 30, 2001, (cases) were compared with those in 157 age-matched volunteer children with asthma of comparable severity studied simultaneously (controls).
  
  
  RESULTS
  Human picornaviruses were detected in 52% of cases and 29% of controls ( P = .002) and viruses of any type in 62% of cases and 41% of controls ( P = .011). Cases were less likely to have been prescribed controller medication (inhaled corticosteroid, 49% vs 85%; P < .0001; leukotriene receptor antagonist, 9% vs 21%; P = .04).
  
  
  CONCLUSIONS
  Respiratory viruses were detected in the majority of children presenting to emergency departments with asthma during the September epidemic of the disease and in a significant minority of children with asthma in the community. The latter were more likely to have anti-inflammatory medication prescriptions than children requiring emergent treatment. Such medication may reduce the risk of emergency department treatment for asthma during the September epidemic.
authors.affiliation: Firestone Institute for Respiratory Health, St. Joseph's Healthcare and McMaster University, Hamilton, Ontario, Canada. njohnsto@sympatico.ca
authors.forename: Neil W
authors.initials: NW
authors.lastname: Johnston
authors.forename: Sebastian L
authors.initials: SL
authors.lastname: Johnston
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Duncan
authors.forename: Justina M
authors.initials: JM
authors.lastname: Greene
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kebadze
authors.forename: Paul K
authors.initials: PK
authors.lastname: Keith
authors.forename: Madan
authors.initials: M
authors.lastname: Roy
authors.forename: Susan
authors.initials: S
authors.lastname: Waserman
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Sears
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology / Q000821:virology*; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006761:Hospitals; D006801:Humans; D006889:Hydroxycorticosteroids / Q000627:therapeutic use; D020024:Leukotriene Antagonists / Q000627:therapeutic use; D008297:Male; D010849:Picornaviridae / Q000302:isolation & purification*; D010850:Picornaviridae Infections / Q000150:complications* / Q000188:drug therapy; D012307:Risk Factors; D012621:Seasons; D011795:Surveys and Questionnaires
chemical_list: D018927:Anti-Asthmatic Agents; D006889:Hydroxycorticosteroids; D020024:Leukotriene Antagonists