Phylogenetic analysis of an off-seasonal influenza virus A (H3N2) in Niigata, Japan, 2010

Clyde Dapat, Yasushi Suzuki, Miyako Kon, Tsutomu Tamura, Reiko Saito, Isolde C. Dapat, Osamu Yamazaki, Takato Odagiri, Seiichiro Fujisaki, Hiroshi Suzuki

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7 Citations (Scopus)


The objective of this study was to characterize the off-seasonal influenza virus A subtype H3N2, which caused an outbreak in an elderly hospital in Niigata, Japan. Virus isolates were sub typed by the hemagglutination-inhibition test and screened for antiviral drug sensitivity by real-time PCR using cycling probe technology and the 50% inhibitory concentration (IC50) method. Whole genome sequencing was performed in order to determine the phylogeny of the outbreak virus. Seven virus isolates were analyzed in this study, and the results showed that all belonged to the influenza virus A (H3N2). These viruses exhibited the S31N mutation in M2, which confers resistance to amantadine. The results of the IC50 analysis showed that these viruses were sensitive to both oseltamivir and zanamivir. Whole genome analysis revealed that the virus was similar to the A/Perth/16/2009 strain and that it is a triple reassortant virus with a 3+3+2 pattern of segment recombination.

Original languageEnglish
Pages (from-to)237-241
Number of pages5
JournalJapanese journal of infectious diseases
Issue number3
Publication statusPublished - 2011
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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