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The molecular epidemiology and evolutionary dynamics of influenza B virus in two Italian regions during 2010-2015: The experience of Sicily and Liguria

  • Autori: Tramuto, F.; Orsi, A.; Maida, C.; Costantino, C.; Trucchi, C.; Alicino, C.; Vitale, F.; Ansaldi, F.
  • Anno di pubblicazione: 2016
  • Tipologia: Articolo in rivista (Articolo in rivista)
  • Parole Chiave: Influenza B; Influenza-like illness; Italy; Liguria; Lineages; Molecular epidemiology; Sicily; Surveillance; Viral evolution; Catalysis; Molecular Biology; Spectroscopy; Computer Science Applications1707 Computer Vision and Pattern Recognition; Physical and Theoretical Chemistry; Organic Chemistry; Inorganic Chemistry
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Molecular epidemiology of influenza B virus remained poorly studied in Italy, despite representing a major contributor to seasonal epidemics. This study aimed to reconstruct the phylogenetic relationships and genetic diversity of the hemagglutinin gene sequences of 197 influenza B strains circulating in both Southern (Sicily) and Northern (Liguria) Italy between 2010 and 2015. Upper respiratory tract specimens of patients displaying symptoms of influenza-like illness were screened by real-time RT-PCR assay for the presence of influenza B virus. PCR-positive influenza B samples were further analyzed by sequencing. Neighbor-joining phylogenetic trees were constructed and the amino-acid alignments were analyzed. Phylogenetic analysis showed clusters in B/Victoria clade 1A/1B (n = 29, 14.7%), and B/Yamagata clades 2 (n = 112, 56.8%) and 3 (n = 56, 28.4%). Both influenza B lineages were found to co-circulate during the study period, although a lineage swap from B/Victoria to B/Yamagata occurred in Italy between January 2011 and January 2013. The most represented amino-acid substitutions were N116K in the 120-loop (83.9% of B/Yamagata clade 3 strains) and I146V in the 150-loop (89.6% of B/Victoria clade 1 strains). D197N in 190-helix was found in almost all viruses collected. Our findings provide further evidence to support the adoption of quadrivalent influenza vaccines in our country.