title: [Applicability of a sensitive duplex real-time PCR assay for identifying B/Yamagata and B/Victoria lineages of influenza virus].
abstract: OBJECTIVE
  To develop a novel sensitive duplex real-time PCR assay for accurately identifying B/Yamagata and B/Victoria lineages of influenza virus type B.
  
  
  METHODS
  50 HA (hemagglutinin) gene sequences coding for B/Yamagata and B/Victoria lineage, respectively, were randomly downloaded for GenBank and analyzed by software MEGA. Primers and probes specific for HA gene of B/Yamagata and B/Victoria lineages were designed by Primer Primer and then applied in the duplex real-time RT-PCR method that was followed developed. Influenza virus B type and A type isolated in our laboratory and typing-confirmed by HAI method were used as reference strains to determine the specificity of this assay and the sensitivity of the duplex amplification was evaluated by viral load testing in terms of in vitro transcribed RNA copy number.
  
  
  RESULTS
  In 2006-2010, 793 influenza virus type B strains were isolated from 17 765 throat swab samples, among which 152 strains were differentiated as By lineage and 641 as Bv lineage by this assay. These results was agreement with that determined by HAI assay. This developed assay allows to accurately identify approximately 10(2) copies/microl for Bv and By lineage virus with intra- and inter-coefficient of variation (CV) < 3.5% and nearly 100% specificity.
  
  
  CONCLUSIONS
  This method provides sensitive and robust tool for routine diagnosis and on-time epidemiological examination of influenza virus, which could be applied in influenza surveillance laboratories for rapid molecular diagnosis.
authors.affiliation: Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China. szcdcssf@yahoo.com.cn
authors.forename: Shi-Song
authors.initials: SS
authors.lastname: Fang
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Xiao-Wen
authors.initials: XW
authors.lastname: Cheng
authors.forename: Xing
authors.initials: X
authors.lastname: Lv
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Wu
authors.forename: Qing
authors.initials: Q
authors.lastname: Zheng
authors.forename: Ren-Li
authors.initials: RL
authors.lastname: Zhang
authors.forename: Jin-Quan
authors.initials: JQ
authors.lastname: Cheng
mesh_terms: D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D009981:Influenza B virus / Q000235:genetics / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus