title: Viral etiologies of lower respiratory tract infections among Egyptian children under five years of age.
abstract: BACKGROUND
  Lower respiratory tract infections (LRTI) are responsible for a considerable number of deaths among children, particularly in developing countries. In Egypt and the Middle East region, there is a lack of data regarding the viral causes of LRTI. In this study, we aimed to identify the relative prevalence of various respiratory viruses that contribute to LRTIs in young children. Although, nucleic acid-based methods have gained importance as a sensitive tool to determine the viral infections, their use is limited because of their prohibitive cost in low-income countries. Therefore, we applied three different laboratory methods, and presented the different virus prevalence patterns detected by each method.
  
  
  METHODS
  We collected nasopharyngeal aspirate samples, demographic data and, clinical data from 450 children under five years of age who presented with LRTI at Abou El Reesh hospital in Cairo during a one-year period. To identify the viral causes of the LRTI we used direct fluorescence assay, real-time reverse-transcriptase polymerase chain reaction (rt-RT-PCR), and shell vial culture. We tested for eight major respiratory viruses.
  
  
  RESULTS
  Two hundred sixty-nine patients (59.9%) had a viral infection, among which 10.8% had a co-infection with two or more viruses. By all three methods, respiratory syncytial virus (RSV) was the most predominant, and parainfluenza virus type 2 (HPIV-2), influenza B virus (FLUBV) were the least predominant. Other viral prevalence patterns differed according to the detection method used. The distribution of various viruses among different age groups and seasonal distribution of the viruses were also determined.
  
  
  CONCLUSIONS
  RSV and human adenovirus were the most common respiratory viruses detected by rt-RT-PCR. Co-infections were found to be frequent among children and the vast majority of co-infections were detected by nucleic acid-based detection assays.
authors.affiliation: US Naval Medical Research Unit No,3, Cairo 11517, Egypt. caroline.fayez.eg@med.navy.mil
authors.forename: Caroline F
authors.initials: CF
authors.lastname: Shafik
authors.forename: Emad W
authors.initials: EW
authors.lastname: Mohareb
authors.forename: Aymen S
authors.initials: AS
authors.lastname: Yassin
authors.forename: Madgy A
authors.initials: MA
authors.lastname: Amin
authors.forename: Amani
authors.initials: A
authors.lastname: El Kholy
authors.forename: Hanaa
authors.initials: H
authors.lastname: El-Karaksy
authors.forename: Fouad G
authors.initials: FG
authors.lastname: Youssef
mesh_terms: D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology / Q000821:virology; D004534:Egypt / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000821:virology; D015995:Prevalence; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000473:pathology / Q000821:virology*; D014773:Virology / Q000379:methods; D014777:Virus Diseases / Q000453:epidemiology* / Q000473:pathology / Q000821:virology*; D014780:Viruses / Q000302:isolation & purification*