H5N1 Bird Flu Strain Detected Across Wildlife on Remote Australian Island

A highly pathogenic H5N1 clade has been confirmed across multiple species on Heard Island, a UNESCO-protected territory 4,000 kilometres southwest of Perth, following seal pup deaths discovered in late 2025. Australian Antarctic Program scientists completed their assessment in June 2026. No mainland incursion has occurred, but migratory seabirds now present the primary surveillance concern for Australian biosecurity authorities.