title: Seasonal variations of respiratory viruses and etiology of human rhinovirus infection in children.
abstract: BACKGROUND
  Using the polymerase chain reaction (PCR) method it is possible to detect uncultivable viruses and discover multiple viral infections. However, the clinical importance of these findings in relation to symptoms is not known.
  
  
  OBJECTIVE
  The seasonal fluctuations of respiratory viruses and the clinical outcomes of single infections and dual infections were investigated.
  
  
  METHODS
  Nasal aspirate samples were obtained from outpatients and inpatients of a children's hospital and these samples were subjected to real-time PCR to detect 16 respiratory viruses. Seasonal variations of the 16 viruses and the clinical outcomes such as wheezing, the need for oxygenation and prolonged hospitalization of patients with single viral infections and multiple infections were determined for the 5 most often detected viruses.
  
  
  RESULTS
  Among 512 specimens analyzed, one or more viruses were detected in 424 (83%) specimens. Two or more viruses were detected in 160 samples (31% of all samples). The epidemic peaks of the viruses did not coincide with each other. Rhinoviruses were the most frequently detected viruses and their coinfection rates were also higher. However, the disease severity in the lower respiratory tract did not differ in most respiratory viral infections regardless of whether there was single infection or dual infection with a rhinovirus and other respiratory virus.
  
  
  CONCLUSIONS
  Seasonal distribution was seen for each virus. There were no significant differences in clinical symptoms in the children studied. Because the infection of rhinoviruses is the common occurrence in children, it is hypothesized that the factors related to disease severity are mainly the underlying conditions of the children.
authors.affiliation: Division of Virology, Department of Infectious Diseases, Osaka Prefectural Institute of Public Health, 1-3-69, Nakamichi, Higashinari-ku, Osaka, 537 0025, Japan. Electronic address: morikawa@iph.pref.osaka.jp.
authors.forename: Saeko
authors.initials: S
authors.lastname: Morikawa
authors.affiliation: Nakano Children's Hospital, 4-13-17, Shinmori, Asahi-ku, Osaka, 535 0022, Japan. Electronic address: kohdera@nakano-kodomo.or.jp.
authors.forename: Urara
authors.initials: U
authors.lastname: Kohdera
authors.affiliation: Nakano Children's Hospital, 4-13-17, Shinmori, Asahi-ku, Osaka, 535 0022, Japan. Electronic address: thosaka@pd6.so-net.ne.jp.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Hosaka
authors.affiliation: Nakano Children's Hospital, 4-13-17, Shinmori, Asahi-ku, Osaka, 535 0022, Japan. Electronic address: kousuke.22.ishii@gmail.com.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Nakano Children's Hospital, 4-13-17, Shinmori, Asahi-ku, Osaka, 535 0022, Japan. Electronic address: shohei@mbk.nifty.com.
authors.forename: Shohei
authors.initials: S
authors.lastname: Akagawa
authors.affiliation: Division of Virology, Department of Infectious Diseases, Osaka Prefectural Institute of Public Health, 1-3-69, Nakamichi, Higashinari-ku, Osaka, 537 0025, Japan. Electronic address: hiroi@iph.pref.osaka.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hiroi
authors.affiliation: Division of Virology, Department of Infectious Diseases, Osaka Prefectural Institute of Public Health, 1-3-69, Nakamichi, Higashinari-ku, Osaka, 537 0025, Japan. Electronic address: kasetetsuo@iph.pref.osaka.jp.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kase
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000821:virology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007297:Inpatients; D008297:Male; D009666:Nose / Q000821:virology*; D060888:Real-Time Polymerase Chain Reaction; D012141:Respiratory Tract Infections / Q000821:virology*; D012229:Rhinovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012621:Seasons; D014777:Virus Diseases / Q000821:virology*
keywords: Clinical severity; Human rhinovirus; Multiple infection; Real-time PCR; Respiratory virus