title: Human respiratory syncytial virus in children with lower respiratory tract infections or influenza-like illness and its co-infection characteristics with viruses and atypical bacteria in Hangzhou, China.
abstract: BACKGROUND
  Human respiratory syncytial virus (RSV) is the most important viral pathogen in children. However, its epidemic patterns and co-infection characteristics are not fully understood.
  
  
  OBJECTIVE
  We attempted to determine the level of genetic variation of RSV, and describe the prevalence and co-infection characteristics of RSV in Hangzhou during two epidemic seasons.
  
  
  METHODS
  Single respiratory samples from 1820 pediatric patients were screened for RSV and genotyped by RT-PCR and sequencing. In all RSV positive specimens, we screened for viruses and atypical bacteria. Demographic and clinical information was recorded and analyzed.
  
  
  RESULTS
  A total of 34.5% and 3.8% of samples from acute lower respiratory tract infections (ALRI) and influenza-like illness (ILI) were positive for RSV, respectively. Phylogenetic analysis revealed that 61.1% of the selected 167 RSV strains were NA1, 31.1% were BA, 3.6% were ON1, 2.4% were CB1, and 1.8% were NA3. A new genotype, BA11 was identified, which comprised 98.1% of BA strains in this study, while the rest were BA10. A total of 36.4% and 9.1% of RSV-positive children with ALRI and ILI respectively were found to be co-infected. Rhinovirus was the most common additional respiratory virus, followed by human metapneumovirus. Except for fever, no significant differences in other clinical presentation between the RSV mono-infection and co-infection groups were observed.
  
  
  CONCLUSIONS
  The circulating RSV strains had high genetic variability with RSV-B showing a more local pattern. In ALRI cases, co-infection of RSV with other viruses or atypical bacteria has no significant effect on the clinical presentation except fever.
authors.affiliation: Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, China. Electronic address: yuxin-fen@163.com.
authors.forename: Xinfen
authors.initials: X
authors.lastname: Yu
authors.affiliation: Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kou
authors.affiliation: College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Daozong
authors.initials: D
authors.lastname: Xia
authors.affiliation: Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Yang
authors.affiliation: Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, China.
authors.forename: Yinyan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: He
mesh_terms: D000208:Acute Disease; D001419:Bacteria / Q000302:isolation & purification; D001424:Bacterial Infections / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D060085:Coinfection / Q000821:virology; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000453:epidemiology; D008297:Male; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D018357:Respiratory Syncytial Virus Infections / Q000150:complications / Q000453:epidemiology* / Q000821:virology*; D018113:Respiratory Syncytial Virus, Human / Q000145:classification / Q000235:genetics*; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D012621:Seasons; D017422:Sequence Analysis, DNA
keywords: Children; Co-infection; Epidemic pattern; Genotype; Human respiratory syncytial virus