Figure 2: Emergence of norovirus GII.17 Kawasaki 2014 during the 2014–2015 winter in Hong Kong.

Maximum likelihood phylogenetic inference of complete and near complete VP1 nucleotide sequences was performed. Gaps in alignment were neglected in the analysis and the final data set contained 1,586 nucleotide positions. Shown are trees with the highest log likelihood. Statistical evaluation was performed by 1,000 bootstrap replications and percentages of clustering (≥80%) are shown at nodes. Magenta and blue squares denote GII.17 Kawasaki 2014 and earlier GII.17 sequences obtained in this study, respectively. Green triangle denotes the first case of GII.17 Kawasaki 2014 in Hong Kong. Purple circles indicate cases selected for saliva-binding assay. Scale bars indicate the number of substitutions per site. Sequence nomenclature: year–month of collection followed by unique sequence identifier (for GII.17 sequences acquired in this study); GenBank accession number followed by unique sequence identifier, country of origin and year of collection (for GII.17 sequences downloaded from GenBank). Country/region abbreviations: AU, Australia; CH, Switzerland; CN, China; GF, French Guiana; JP, Japan; NP, Nepal; TW, Taiwan; US, the United States of America.