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Infect Genet Evol. 2018 Apr 14. pii: S1567-1348(18)30194-1. doi: 10.1016/j.meegid.2018.04.016. [Epub ahead of print]
Neuraminidase inhibitor susceptibility and evolutionary analysis of human influenza B isolates from three Asian countries during 2012-2015.
Hibino A1, Massaad E2, Kondo H3, Saito R4, Odagiri T3, Takemae N5, Tsunekuni R5, Saito T5; Japanese Influenza Collaborative Study Group, Kyaw Y6, Lin N7, Myint YY8, Tin HH8, Le Khanh Hang N9, Mai LQ9, Yagami R10, Shobugawa Y10, Lam T11, Zaraket H12.
Author information
Abstract
Influenza B viruses of both the Yamagata and the Victoria lineages are implicated in a large proportion of the morbidity and mortality associated with influenza outbreaks. In this study, we characterized the full genomes of 53 influenza B viruses isolated during 2012-2015 in three Asian countries: Japan, Myanmar, and Vietnam. Analysis of the hemagglutinin (HA) genes revealed co-circulation of both the Yamagata and Victoria lineages within the same season in these countries. Our analysis revealed, that a large proportion of viruses circulating during 2013-2014 in Japan and Vietnam were mismatched to the vaccine supporting the rationale for using quadrivalent vaccines. Molecular analysis of the neuraminidase (NA) genes did not reveal any of the previously reported substitutions associated with reduced susceptibility to neuraminidase inhibitors (NAIs). However, one isolate from Nagasaki displayed reduced inhibition by NAIs, associated with an NA-M426I substitution (N2-numbering). Phylogenetic analysis of the eight genome segments identified a 6 + 2 reassortant strain belonging to the Victoria lineage that circulated in Japan during the 2013-2014 season. This strain appears to have evolved from a descendent of a B/Brisbane/60/2008-like strain in an intra-lineage reassortment event involving the nucleoprotein (NP) and nonstructural (NS) genes. Therefore, influenza B strains circulating worldwide continue to evolve via complex reassortment events, which contribute to their survival and the emergence of new strains. These findings highlight the need for ongoing genome-wide studies of circulating viruses and assessing the implications of these evolutionary events on the vaccines.
KEYWORDS:
Asia; Influenza B; Neuraminidase inhibitors; Reassortment; Reduced susceptibility
PMID: 29665435 DOI: 10.1016/j.meegid.2018.04.016
Neuraminidase inhibitor susceptibility and evolutionary analysis of human influenza B isolates from three Asian countries during 2012-2015.
Hibino A1, Massaad E2, Kondo H3, Saito R4, Odagiri T3, Takemae N5, Tsunekuni R5, Saito T5; Japanese Influenza Collaborative Study Group, Kyaw Y6, Lin N7, Myint YY8, Tin HH8, Le Khanh Hang N9, Mai LQ9, Yagami R10, Shobugawa Y10, Lam T11, Zaraket H12.
Author information
Abstract
Influenza B viruses of both the Yamagata and the Victoria lineages are implicated in a large proportion of the morbidity and mortality associated with influenza outbreaks. In this study, we characterized the full genomes of 53 influenza B viruses isolated during 2012-2015 in three Asian countries: Japan, Myanmar, and Vietnam. Analysis of the hemagglutinin (HA) genes revealed co-circulation of both the Yamagata and Victoria lineages within the same season in these countries. Our analysis revealed, that a large proportion of viruses circulating during 2013-2014 in Japan and Vietnam were mismatched to the vaccine supporting the rationale for using quadrivalent vaccines. Molecular analysis of the neuraminidase (NA) genes did not reveal any of the previously reported substitutions associated with reduced susceptibility to neuraminidase inhibitors (NAIs). However, one isolate from Nagasaki displayed reduced inhibition by NAIs, associated with an NA-M426I substitution (N2-numbering). Phylogenetic analysis of the eight genome segments identified a 6 + 2 reassortant strain belonging to the Victoria lineage that circulated in Japan during the 2013-2014 season. This strain appears to have evolved from a descendent of a B/Brisbane/60/2008-like strain in an intra-lineage reassortment event involving the nucleoprotein (NP) and nonstructural (NS) genes. Therefore, influenza B strains circulating worldwide continue to evolve via complex reassortment events, which contribute to their survival and the emergence of new strains. These findings highlight the need for ongoing genome-wide studies of circulating viruses and assessing the implications of these evolutionary events on the vaccines.
KEYWORDS:
Asia; Influenza B; Neuraminidase inhibitors; Reassortment; Reduced susceptibility
PMID: 29665435 DOI: 10.1016/j.meegid.2018.04.016