title: Characterization of human metapneumovirus from pediatric patients with acute respiratory infections in a 4-year period in Beijing, China.
abstract: BACKGROUND
  Human metapneumovirus (hMPV) was discovered by scientists in the Netherlands as a novel respiratory virus in 2001 and had been found in children with acute respiratory tract infections (ARTI) in China. The objective of this study was to determine the importance of hMPV infection in children in Beijing and the genotypes of the circulating virus by the surveillance during a four-consecutive-year period.
  
  
  METHODS
  Clinical specimens collected from children with ARTI from January 2006 to December 2009 were tested for hMPV by RT-PCR using primers targeting the matrix (M) gene, followed by genotyping of hMPV directly from positive samples by diplex PCR with primers for glycoprotein (G) genes. Sequence analysis was used for genotyping of those un-typable samples. Common respiratory viruses in these clinical specimens were tested by virus isolation and antigen detection, in addition to hMPV detection.
  
  
  RESULTS
  Of 4730 tested specimens, 191 (4.0%) were positive for hMPV and 62.8% of 191 were identified as genotype A. The positive rate of hMPV from hospitalized patients was higher than that from outpatients each year. Most of hMPV positive children were under five years old. The peak of hMPV activity mostly occurred in late spring and overlapped with or followed that of respiratory syncytial virus (RSV) and followed by parainfluenza virus 3. Of hMPV infected cases, 68.6% were lower respiratory tract infection, among which 79.4% were hospitalized, and upper respiratory tract infection was diagnosed for 31.4% of hMPV infected children. The 9.4% of hMPV positive samples were found to co-exist with other respiratory viruses.
  
  
  CONCLUSIONS
  hMPV was an important pathogen for ARTI in pediatric patients, especially those under five years old. Both genotypes A and B circulated simultaneously in Beijing.
authors: Laboratory of Virology, Peking University Capital Institute of Pediatrics Teaching Hospital, Beijing 100020, China.
authors: Ru-Nan
authors: RN
authors: Zhu
authors: Yuan
authors: Y
authors: Qian
authors: Lin-Qing
authors: LQ
authors: Zhao
authors: Jie
authors: J
authors: Deng
authors: Yu
authors: Y
authors: Sun
authors: Fang
authors: F
authors: Wang
authors: Bin
authors: B
authors: Liao
authors: Yan
authors: Y
authors: Li
authors: Rong-Yan
authors: RY
authors: Huang
mesh_terms: D000293:Adolescent; D002681:China; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D029121:Metapneumovirus / Q000235:genetics* / Q000472:pathogenicity; D012141:Respiratory Tract Infections / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction