Global spread of H5N1

Spread of bird flu Highly pathogenic H5N1 Highly pathogenic H5N1 Countries that have reported deaths of poultry or wild birds linked to highly pathogenic H5N1 infection as of March 2023. Countries that have reported human cases of highly pathogenic H5N1 infection. The global spread of H5N1 influenza in birds is considered a significant pandemic threat. While other H5N1 influenza strains are known, they are significantly different on a genetic level from a highly pathogenic, emergent strain of H5N1, which was able to achieve hitherto unprecedented global spread in 2008. The H5N1 strain is a fast-mutating, highly pathogenic avian influenza virus (HPAI) found in multiple bird species. It is both epizootic (an epidemic in non-humans) and panzootic (a disease affecting animals of many species especially over a wide area). Unless otherwise indicated, "H5N1" in this timeline refers to the 2008 highly pathogenic strain of H5N1. Cumulative Human Cases of and Deaths from H5N1As of April 11, 2007 Notes: Source WHO Confirmed Human Cases of H5N1 "[T]he incidence of human cases peaked, in each of the three years in which cases have occurred, during the period roughly corresponding to winter and