Phylogenetic and Molecular Characteristics of Wild Bird-Origin Avian Influenza Viruses Circulating in Poland in 2018−2022: Reassortment, Multiple Introductions, and Wild Bird–Poultry Epidemiological Links

Figure 2

Graphical representations of HPAIV subtypes and genotypes detected during two consecutive H5Nx HPAI seasons in 2020–2022 in Poland along with their evolutionary relationships. (a) Genetic network of HA (H5) sequences collected from wild birds (colorful circles) and poultry (gray circles). Small-diameter circles represent unique sequences, while large-diameter circles encompass groups of phylogenetically similar sequences. (b) Identified HPAIV subtypes/genotypes along with undergoing reassortment events. For reassortants, AIV genes clustering phylogenetically with seasonally dominant genotypes such as H5N8 and H5N1-G1 were colored in red and pink, respectively. Exchanged gene segments are indicated corresponding to the color scheme used in the HA genetic network (H5N1-G6 was not included in the network analysis).

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