The global spread of H5N8 avian influenza viruses is a public health concern The first confirmed outbreak of highly pathogenic avian influenza virus (HPAIV) in birds was documented in Scotland in 1959 with the influenza A H5N1 subtype, although there have been numerous suspected HPAIV outbreaks documented globally since 1878. H5N1 and its genetic reassortants (including H5N2, H5N5, H5N6, and H5N8) have been found to cause thousands of outbreaks worldwide ( 1 , 2 ) in both farmed poultry and wild birds, with massive mortality. The H5Ny HPAIVs are lethal to most farmed poultry, and culling is often used to prevent further spread. Several of the H5Ny AIVs have zoonotic and pandemic potential because they have been demonstrated to cross the species barrier, transmitting to mammals, including humans. Eurasia and Africa are experiencing a new wave of highly pathogenic H5Ny AIV outbreaks. The zoonotic potential of AIVs warrants continuous, vigilant monitoring to avert further spillovers that could result in disastrous pandemics.