H5N1 Bird Flu Kills Thousands of Sub‑Antarctic Seal Pups, Traced to Crozet Islands
A deadly H5N1 bird flu outbreak has killed an estimated 13,000 southern elephant seal pups on Heard Island and McDonald Island, with a 76% mortality rate across about 17,000 births; several hundred adult king penguins have also died. Genetic data suggest the virus arrived from the French Crozet Islands around August 2025 and has been spreading eastward through sub‑Antarctic wildlife, a finding reported in BioRxiv (not yet peer‑reviewed).