Epidemiological Update Avian Influenza A(H5) in the Americas Region - 26 August 2026

Avian influenza A(H5) is a highly contagious viral disease that primarily affects poultry and wild birds, with the ability to sporadically infect mammalian species, including humans. Since 1996, the A/goose/Guangdong/1/96 lineage has caused recurrent outbreaks in bird populations, as well as hundreds of human cases and deaths resulting from exposure to infected animals or contaminated environments. Currently, the A(H5N1) subtype and other avian influenza A(H5) viruses have been identified in birds and mammals across multiple geographic regions worldwide.

Between 2021 and March 2026, more than 600 species of wild and poultry birds and more than 100 species of mammals have been reported as affected by avian influenza viruses with zoonotic potential, such as A(H5Nx). In May 2026, the Food and Agriculture Organization of the United Nations (FAO), the World Organization for Animal Health (WOAH), and the World Health Organization (WHO) determined that the global public health risk associated with highly pathogenic avian influenza viruses (HPAI) A(H5) belonging to the Gs/Gd lineage remains low. Similarly, for people with occupational or frequent exposure, the risk was estimated to be low to moderate.