title: Community-acquired respiratory viruses and co-infection among patients of Ontario sentinel practices, April 2009 to February 2010.
abstract: BACKGROUND
  Respiratory viruses are known to cocirculate but this has not been described in detail during an influenza pandemic.
  
  
  OBJECTIVE
  To describe respiratory viruses, including co-infection and associated attributes such as age, sex or comorbidity, in patients presenting with influenza-like illness to a community sentinel network, during the pandemic A(H1N1)pdm09 in Ontario, Canada.
  
  
  METHODS
  Respiratory samples and epidemiologic details were collected from 1018 patients with influenza-like illness as part of respiratory virus surveillance and a multiprovincial case-control study of influenza vaccine effectiveness.
  
  
  RESULTS
  At least one virus was detected in 668 (65·6%) of 1018 samples; 512 (50·3%) had single infections and 156 (15·3%) co-infections. Of single infections, the most common viruses were influenza A in 304 (59·4%) samples of which 275 (90·5%) were influenza A(H1N1)pdm09, and enterovirus/rhinovirus in 149 (29·1%) samples. The most common co-infections were influenza A and respiratory syncytial virus B, and influenza A and enterovirus/rhinovirus. In multinomial logistic regression analyses adjusted for age, sex, comorbidity, and timeliness of sample collection, single infection was less often detected in the elderly and co-infection more often in patients <30 years of age. Co-infection, but not single infection, was more likely detected in patients who had a sample collected within 2 days of symptom onset as compared to 3-7 days.
  
  
  CONCLUSIONS
  Respiratory viral co-infections are commonly detected when using molecular techniques. Early sample collection increases likelihood of detection of co-infection. Further studies are needed to better understand the clinical significance of viral co-infection.
authors.affiliation: Public Health Ontario, Toronto, ON, Canada.
authors.forename: Adriana
authors.initials: A
authors.lastname: Peci
authors.forename: Anne-Luise
authors.initials: AL
authors.lastname: Winter
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Gubbay
authors.forename: Danuta M
authors.initials: DM
authors.lastname: Skowronski
authors.forename: Elizabeth I
authors.initials: EI
authors.lastname: Balogun
authors.forename: Cedric
authors.initials: C
authors.lastname: De Lima
authors.forename: Natasha S
authors.initials: NS
authors.lastname: Crowcroft
authors.forename: Anu
authors.initials: A
authors.lastname: Rebbapragada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology* / Q000821:virology; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000821:virology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007251:Influenza, Human / Q000150:complications*; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000821:virology; D012307:Risk Factors; D014780:Viruses / Q000145:classification / Q000302:isolation & purification*; D055815:Young Adult