Alert and surveillance on H5N1 influenza virus: risks to agriculture and public health

<p dir="ltr">Bird flu, primarily caused by avian influenza A viruses, poses significant pandemic threats due to antigenic drift and shift. The highly pathogenic avian influenza (HPAI) A(H5N1) virus has caused global outbreaks in birds, killing millions of wild birds and poultry, with sporadic cases in humans often being fatal with a case fatality rate of 52% (893 cases in 24 countries between 2003 and 2024, with 463 deaths) reaching all continents. The 2009 H1N1 pandemic demonstrated the risks of reassortment between human, avian and swine influenza viruses.</p>