Figure 3.

Maximum-likelihood phylogenetic tree for the neuraminidase (NA) gene in study of highly pathogenic avian influenza virus A(H5N1) infection in cats, South Korea, 2023. The phylogenetic tree is based on sequences of H5N1 NA sequences of viruses isolated recently, as well as on the HA gene sequence of other H5Nx viruses. Bootstrap values (1,000 replicates) >70% are displayed at the branch nodes. The black circle denotes virus isolated from poultry in South Korea, 2022–2023, and the black triangle denotes viruses isolated from raw duck meat used for cat food. The blue shaded square denotes viruses isolated from cats in shelter 1, and the red square indicates viruses isolated from cats in shelter 2. The blue outlined square indicates viruses isolated from cats in shelter 1 by SNU. Scale bar indicates number of nucleotide substitutions per site. SNU, Seoul National University.