Volume 23, Number 4—April 2017
Antiviral Drug–Resistant Influenza B Viruses Carrying H134N Substitution in Neuraminidase, Laos, February 2016
|Virus name, passage history§
||Amino acid change in virus genes†
||Date specimen collected
HA, hemagglutinin; ILI, influenza-like illness; M1, matrix protein 1; NA, neuraminidase; NS1, nonstructural protein 1; SARI, severe acute respiratory illness; –, indicates same amino acid residue as in the consensus sequence of B-Victoria viruses that were circulating in Laos during the 2015‒16 influenza season.
†Strain-specific amino acid sequence numbering is used. Sequences for all 8 gene segments were generated using the MiSeq sequencing system (Illumina Inc., San Diego, CA, USA) (14) (Technical Appendix Table 1). Data are amino acid differences in protein-coded regions of NA, HA, M1, and NS1 genes compared with the consensus sequence. Not shown: synonymous nucleotide mutations that were common for the NA-H134N viruses: PB1-c93t, PB1-g1930a, and HA-g1520a. In addition, NA-H134N viruses differed from each other by the following synonymous nucleotide mutations: B/Laos/0406/2016 possessed NS1-g345a, B/Laos/0525/2016 possessed NA-t762a, NS1-a561g, and B/Laos/0654/2016 possessed NS2-g186a.
‡Corresponds to position 219 in NS1 protein numbering used by Ma et al. (15).
§Original indicates specimen collected from patient; C1 and C2 indicates virus propagated once or 2 times on MDCK cells.
¶Presence of the NA-H134N substitution in the original respiratory specimens was confirmed by a pyrosequencing assay (see Figure 1) (Technical Appendix Table 2).
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