Global Report on High Pathogenicity Avian Influenza in Antarctica and sub-Antarctic Islands

Geographical isolation and extreme climates have resulted in the long isolation of Antarctica and sub-Antarctic islands. The result is a unique assemblage of animals, many endemics to the region. Low pathogenicity avian influenza is present in Antarctica; however, we have a poor understanding of the epidemiology, ecology and evolution of these viruses in the region. Of concern is the arrival of high pathogenicity avian influenza (HPAI) H5N1 clade 2.3.4.4b in the austral summer of 2023/24, and subsequent range expansion in the 2024/25 austral summer. Herein we review data and information from the literature (including all pre-prints, reports, and press releases), providing a narrative of events in the sub-Antarctic and Antarctica. We also address the impacts of HPAI H5N1 on Antarctic wildlife, and the unique challenges of working in the region.