A novel highly pathogenic avian influenza (HPAI) H5N8 virus, first detected in January 2014 in poultry and wild birds in South Korea, has spread throughout Asia and Europe, and caused outbreaks in Canada and the United States by the end of the year. The spread of H5N8 and the novel reassortant viruses, H5N2 and H5N1 (H5Nx), in domestic poultry across multiple states in the U.S. pose a potential public health risk. To evaluate the potential of cross-species infection, we determined the pathogenesis and transmissibility of two Asian-origin H5Nx viruses in mammalian animal models.
