Figure 1.
Phylogenetic trees comparing the haemagglutinin nucleotide sequences of 2017/18 Korean influenza A(H5N6) viruses, South Korea, December 2017 (n = 4)
Bdk: broiler duck; Brk: breeder duck; BT: baikal teal; CK: chicken; CT: common teal; DK: duck; EHG: Eurasian herring gull; EM: environment; FP: ferruginous pochard; GBG: great black backed gull; GH: grey heron; GS: goose; HA: haemagglutinin; MD: mallard; Mdk: mallard duck; MS: mute swan; NS: northern shoveler; PC: peacock; PS: painted stork; RS: ruddy shelduck; SB: spoonbill; TD: tufted duck; WD: wild duck.
To investigate the origins of novel influenza A(H5N6) viruses (A/AP/Korea/W612/2017, A/AP/Korea/W613/2017, A/AP/Korea/W614/2017 and A/AP/Korea/W615/2017: marked with asterisks), full-length nucleotide sequences of HA genes were compared with available H5Nx and high blast-scoring virus sequences from GenBank and the Global Initiative on Sharing All Influenza Data (GISAID). The deposited GenBank accession numbers of HA genes are MG891804–MG891807; GISAID sequences are acknowledged in Supplement 1. Time-scaled phylogenies (dates shown on the horizontal axis) were inferred using strict-clock Bayesian Markov Chain Monte Carlo analysis. The month of isolation is indicated at the end of the virus name.
The yellow line indicates the 2016/17 influenza A(H5N6) subtypes while the blue line indicates the 2017/18 H5N6 subtype which was isolated from South Korea. The Group A of clade 2.3.4.4 viruses comprises influenza A(H5N8) viruses identified in South Korea in the 2013/14 and 2014/15 winter seasons. Group B comprises H5N8, H5N6 and H5N5 viruses identified in Asia and Europe during the 2013/14 to 2017/18 winter seasons. Group C of clade 2.3.4.4 viruses comprises H5N6 viruses identified in China and South Korea during the 2015/16 and 2017/18 winter seasons, respectively.
