title: Detection and quantification of human metapneumovirus in pediatric specimens by real-time RT-PCR.
abstract: BACKGROUND
  Human metapneumovirus (h MPV), a recently identified virus, causes respiratory illness in children.
  
  
  OBJECTIVE
  A real-time reverse transcription-polymerase chain reaction (RT-PCR) assay was developed and used to detect and quantify h MPV in respiratory specimens.
  
  
  METHODS
  The quantitative RT-PCR assay amplified an approximately 70 base pair fragment from the h MPV fusion protein gene. The assay was validated and used to test respiratory specimens obtained from children seen at a hospital in Seattle, Washington, from December 2002 through May 2003.
  
  
  RESULTS
  The assay detected 1000 h MPV copies/mL of specimen, did not detect 19 other respiratory viruses, and was able to detect and accurately quantify isolates from the four known h MPV genetic lineages in a proficiency panel of 20 previously tested samples. h MPV was detected in 52 (7.2%) of 719 pediatric respiratory specimens. The mean log10 copies/mL of h MPV in the 52 positive specimens was 7.67 (range=4.59-10.60). Children aged 7-12 months had a significantly higher h MPV prevalence (12.4%) than did children younger than 7 months (4.7%) (P<0.005). Children in this age group also had significantly higher levels of h MPV in their respiratory specimens (mean log 8.43 copies/mL) than did the younger children (mean log 6.93 copies/mL) (P=0.0025).
  
  
  CONCLUSIONS
  The rapid real-time RT-PCR assay described here is a sensitive test for clarifying the epidemiology of and diseases associated with h MPV.
authors.affiliation: Department of Laboratory Medicine, University of Washington, CHRMC, 4800 Sand Point Way N.E., Virology Office, G-815, 8G-3, Seattle, WA 98105, USA. jane.kuypers@seattlechildrens.org
authors.forename: Jane
authors.initials: J
authors.lastname: Kuypers
authors.forename: Nancy
authors.initials: N
authors.lastname: Wright
authors.forename: Lawrence
authors.initials: L
authors.lastname: Corey
authors.forename: Rhoda
authors.initials: R
authors.lastname: Morrow
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D029121:Metapneumovirus / Q000235:genetics / Q000302:isolation & purification*; D018184:Paramyxoviridae Infections / Q000175:diagnosis* / Q000821:virology*; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D015203:Reproducibility of Results; D012137:Respiratory System / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D012367:RNA, Viral