A Case Study of Highly Pathogenic Avian Influenza H5N1 At Bird Island, South Georgia: The First Documented Outbreak in the subantarctic region

The spread of the high pathogenicity avian influenza (HPAI) H5N1 subtype has had dramatic impacts on commercial poultry farms and numerous populations of wild birds and mammals. Here we document the detection, monitoring, and impact of the first documented outbreak of H5N1 HPAI in the subantarctic region, at Bird Island (South Georgia). Mortalities from HPAI were first suspected in September 2023, and later confirmed by genetic analysis. Infections were confirmed initially in three bird species, wandering albatross (Diomedea exulans), brown skua (Stercorarius antarcticus), and gentoo penguin (Pygoscelis papua), and later also in the Antarctic fur seal (Arctocephalus gazella). In total, 77 brown skuas, 38 gentoo penguins, and 58 wandering albatrosses are considered to have died from HPAI infections, and HPAI was confirmed in five Antarctic fur seals. Total mortality is unknown for all species as other individuals will have been scavenged before discovery or died at sea. This report is presented as a case study, including details of the management, risk, safety considerations, and ethical decisions regarding animal welfare and research. As such, the lessons learned may help guide research and management responses to HPAI outbreaks elsewhere, particularly in remote areas or in species of conservation concern.