Clade 2.3.4.4 H5 influenza virus was introduced to Taiwan most likely by migratory birds.
These viruses were closely related with the Japanese and North American isolates.
Multiple variants were generated after the reassortment with Eurasian gene pool.
Co-circulation of Mexican/95-like H5N2 viruses was identified during the outbreak.
Clade 2.3.4.4 H5 virus could potentially become established and enzootic in Taiwan.