title: Clinical and epidemiologic factors related to subsequent wheezing after virus-induced lower respiratory tract infections in hospitalized pediatric patients younger than 3 years.
abstract: Most wheezing episodes in infants are caused and exacerbated by virus-induced lower respiratory tract infections. However, there are few reports of epidemiologic and clinical virus-specific research with a focus on virus-induced wheezing. The purpose of the current study was to characterize the clinical presentation of virus-induced wheezing in pediatric patients <3 years of age who were hospitalized with lower respiratory tract infections. Of the 412 patients in the study, 216 were followed for 3 years. Nasopharyngeal aspirates collected from the patients at the time of admission were examined for the presence of respiratory syncytial virus (RSV), rhinovirus (RV), parainfluenza-3 virus (PIV-3), human metapneumovirus (hMPV), and influenza virus (Flu) using reverse-transcription polymerase chain reaction and rapid diagnostic tests. Clinical signs were assessed using a severity scoring system. In patients with wheezing at the time of admission, RSV, RV, RSV+RV, Flu, PIV-3, and hMPV were detected in 33, 14, 8, 8, 5, and 3 % of samples, respectively. There were no differences in age and severity scores between patients harboring more prevalent viruses (RSV and RV) and those with less common infections. Patients with wheezing and RV-positive aspirates at the time of admission were more likely to develop subsequent wheezing during the following 3 years.
  
  
  CONCLUSIONS
  RSV and RV infections are factors in the development and exacerbation of wheezing after virus-induced lower respiratory tract infections. Moreover, RV-induced wheezing may be associated with subsequent recurrent wheezing and the development of asthma.
authors.affiliation: Department of Pediatrics, Soma General Hospital, 142 Tubogasaku-Niinuma, Soma City, Fukushima, 976-0011, Japan, ayatake@rondo.ocn.ne.jp.
authors.forename: Aya
authors.initials: A
authors.lastname: Takeyama
authors.forename: Koichi
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Masatoki
authors.initials: M
authors.lastname: Sato
authors.forename: Toshiko
authors.initials: T
authors.lastname: Sato
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Tomita
authors.forename: Ryo
authors.initials: R
authors.lastname: Maeda
authors.forename: Masaki
authors.initials: M
authors.lastname: Ito
authors.forename: Masahiko
authors.initials: M
authors.lastname: Katayose
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Kawasaki
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Hosoya
mesh_terms: D001990:Bronchiolitis, Viral / Q000150:complications* / Q000453:epidemiology* / Q000821:virology; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D012135:Respiratory Sounds / Q000209:etiology*; D012720:Severity of Illness Index