title: Viral infections in outpatients with medically attended acute respiratory illness during the 2012-2013 influenza season.
abstract: BACKGROUND
  While it is known that acute respiratory illness (ARI) is caused by an array of viruses, less is known about co-detections and the resultant comparative symptoms and illness burden. This study examined the co-detections, the distribution of viruses, symptoms, and illness burden associated with ARI between December 2012 and March 2013.
  
  
  METHODS
  Outpatients with ARI were assayed for presence of 18 viruses using multiplex reverse transcriptase polymerase chain reaction (MRT-PCR) to simultaneously detect multiple viruses.
  
  
  RESULTS
  Among 935 patients, 60% tested positive for a single virus, 9% tested positive for ≥1 virus and 287 (31%) tested negative. Among children (<18 years), the respective distributions were 63%, 14%, and 23%; whereas for younger adults (18-49 years), the distributions were 58%, 8%, and 34% and for older adults (≥50 years) the distributions were 61%, 5%, and 32% (P < 0.001). Co-detections were more common in children than older adults (P = 0.01), and less frequent in households without children (P = 0.003). Most frequently co-detected viruses were coronavirus, respiratory syncytial virus, and influenza A virus. Compared with single viral infections, those with co-detections less frequently reported sore throat (P = 0.01), missed fewer days of school (1.1 vs. 2 days; P = 0.04), or work (2 vs. 3 days; P = 0.03); other measures of illness severity did not vary.
  
  
  CONCLUSIONS
  Among outpatients with ARI, 69% of visits were associated with a viral etiology. Co-detections of specific clusters of viruses were observed in 9% of ARI cases particularly in children, were less frequent in households without children, and were less symptomatic (e.g., lower fever) than single infections.
authors.affiliation: Department of Family Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. zimmer@pitt.edu.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Zimmerman
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. Rinaldo@pitt.edu.|Departments of Infectious Disease and Microbiology, and Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA. Rinaldo@pitt.edu.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Rinaldo
authors.affiliation: Department of Family Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. tnowalk@pitt.edu.
authors.forename: Mary Patricia
authors.initials: MP
authors.lastname: Nowalk
authors.affiliation: Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA. balagk@edc.pitt.edu.
authors.forename: G K
authors.initials: GK
authors.lastname: Balasubramani
authors.affiliation: Department of Family Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. moehlkingkk2@upmc.edu.
authors.forename: Krissy K
authors.initials: KK
authors.lastname: Moehling
authors.affiliation: Departments of Infectious Disease and Microbiology, and Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA. bullottaac@upmc.edu.
authors.forename: Arlene
authors.initials: A
authors.lastname: Bullotta
authors.affiliation: Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA. eng@edc.pitt.edu.
authors.forename: Heather F
authors.initials: HF
authors.lastname: Eng
authors.affiliation: Department of Family Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. raviottaj@upmc.edu.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Raviotta
authors.affiliation: Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA. saxt@edc.pitt.edu.
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Sax
authors.affiliation: Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA. wisniew@edc.pitt.edu.
authors.forename: Stephen
authors.initials: S
authors.lastname: Wisniewski
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology / Q000821:virology*; D008297:Male; D008875:Middle Aged; D010045:Outpatients / Q000706:statistics & numerical data*; D010414:Pennsylvania / Q000453:epidemiology; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000150:complications / Q000453:epidemiology / Q000821:virology*; D012621:Seasons; D055815:Young Adult