title: Human metapneumovirus in infants and young children in Thailand with lower respiratory tract infections; molecular characteristics and clinical presentations.
abstract: Human metapneumovirus (hMPV) is a recently identified Paramyxovirus. The clinical features and molecular characteristics of hMPV in Asian populations have so far remained obscure.
  
  
  OBJECTIVE
  The present study was designed to investigate the prevalence of hMPV in infants and young children presented with acute lower respiratory tract infection (ALRI) and to identify the molecular characteristics and clinical presentations.
  
  
  METHODS
  There were 236 nasopharyngeal secretions (NPs) collected from infants and children presented with ALRI at King Chulalongkorn Memorial hospital between March 2001 and September 2003. Reverse transcriptase-polymerase chain reaction (RT-PCR) applying specific primers was done to identify hMPV and hRSV. Phylogenetic analysis of hMPV N, F and L genes was also performed.
  
  
  RESULTS
  Of the 220 (236) infants and young children tested, positive results were found in 12 specimens (5.4%). The mean age of children with hMPV infections was 22+/-11 months. They mostly presented with fever with cough (100%) and upper respiratory tract symptoms (10/12, 83%). Eleven of twelve infants (92%) were hospitalized. Additionally, phylogenetic analysis identified two distinct lineages of hMPV.
  
  
  CONCLUSIONS
  Our results demonstrated the prevalence, molecular characterization and clinical spectrum of hMPV infection in infants and young children presented with lower respiratory tract infections in Thailand.
authors.affiliation: Respiratory and Critical Care Unit, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Rujipat
authors.initials: R
authors.lastname: Samransamruajkit
authors.forename: Wanida
authors.initials: W
authors.lastname: Thanasugarn
authors.forename: Nuanchan
authors.initials: N
authors.lastname: Prapphal
authors.forename: Apiradee
authors.initials: A
authors.lastname: Theamboonlers
authors.forename: Yong
authors.initials: Y
authors.lastname: Poovorawan
mesh_terms: D001483:Base Sequence; D002675:Child, Preschool; D017931:DNA Primers / Q000737:chemistry; D004279:DNA, Viral / Q000737:chemistry; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D029121:Metapneumovirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D009305:Nasopharynx / Q000821:virology; D018184:Paramyxoviridae Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D010802:Phylogeny; D015995:Prevalence; D012136:Respiratory Syncytial Viruses / Q000235:genetics / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013785:Thailand / Q000453:epidemiology
chemical_list: D017931:DNA Primers; D004279:DNA, Viral