title: [Mutations in the Neuraminidase Gene of the Epidemic Influenza Virus Strain Isolated in the 2012-2013 Season and Improvement of a PCR Assay for the Detection of Influenza Virus].
abstract: In 2011, we developed a real-time RT-PCR method to rapidly and sensitively detect three subtypes of influenza A virus [H1N1, H3N2, and influenza (H1N1) 2009] and influenza B virus (the conventional PCR method). This method was useful during the 2011-2012 epidemic season. However, epidemic influenza A virus strain H3N2 in the 2012-2013 season was undetectable by this method, possibly due to mutation in the neuraminidase (NA) gene of epidemic influenza A virus strain H3N2. Therefore, we improved the method by using the hemagglutinin (HA) gene instead of the NA gene as the target for the detection of influenza A virus strain H3N2. In addition, this improved PCR method also included a PCR detection system for the matrix (M) gene, well conserved and common to all influenza A virus strains. As a result, influenza A virus strain H3N2, which was undetectable by the conventional PCR method, was positive by the improved PCR method. Testing of specimens from 219 influenza-like illness patients during the 2012-2013 season by the influenza antigen immunochromatographic assay and conventional and improved PCR methods showed influenza virus A-positive rates of 24.2, 1.8, and 28.3%, respectively. All influenza A virus strains were positive for the M gene (in 62 [28.3%] of the 219 patients). These results suggest that the improved PCR method can determine the presence or absence of influenza A virus infection, even if a mutation in the HA or NA gene occurs in the future.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Yanagita
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kuwamura
authors.forename: Satoru
authors.initials: S
authors.lastname: Kinoshita
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakajima
authors.forename: Syuichi
authors.initials: S
authors.lastname: Tomizawa
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ozawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006388:Hemagglutinins / Q000235:genetics; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification; D053122:Influenza A Virus, H3N2 Subtype / Q000235:genetics* / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009439:Neuraminidase / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods
chemical_list: D006388:Hemagglutinins; D009439:Neuraminidase