H5N1 Bird Flu

About H5N1 Bird Flu

H5N1 highly pathogenic avian influenza HPAI was first identified in a goose in Guangdong province, China, in 1996. The virus infects poultry and wild birds. Human infections were first reported in Hong Kong in 1997, with 18 cases and 6 deaths. The Hong Kong government culled 1.5 million chickens to contain the outbreak. From 2003 to 2024, the WHO recorded more than 900 human H5N1 cases in about two dozen countries, roughly half of them fatal. Most human cases involved direct contact with infected poultry. The virus has not acquired the ability to transmit efficiently between humans. H5N1 has spread globally through wild bird migration, reaching North America in late 2021 and South America in 2022. In 2024, H5N1 was detected in US dairy cattle, and dozens of mostly mild human cases, chiefly among farm workers, were reported in the US. Many experts consider H5N1 a leading candidate for a future influenza pandemic. Vaccine stockpiles exist but would need to be updated for circulating strains.