Fig. 1. Schematic diagram of reassortment among clade 2.3.4.4b highly pathogenic avian influenza viruses (HPAIVs) in Eurasia. Each oval represents a viral isolate, within which the eight gene segments (from the top to the bottom: PB2, PB1, PA, HA, NP, NA, M, and NS) are indicated by horizontal bars. The color of each bar identifies its origin. The H5N8 B1 ancestor is indicated by light green. The original genes of the B0 ancestor are shown in gray. Other colors represent different Eurasian avian influenza lineages.