Deadly Bird Flu Outbreak Kills Hundreds of Seal Pups on Remote Antarctic Island

On October 24, 2025, Australian scientists reported a concerning discovery on Heard Island in the sub-Antarctic region. Hundreds of dead seal pups were found on the island, with signs indicating they were killed by the deadly H5N1 bird flu virus.

The virulent strain of H5N1 has been sweeping through wild bird and mammal populations since 2021, causing millions of deaths and infecting poultry and dairy farms, as well as some farmworkers. While the detection on Heard Island is not yet confirmed, the symptoms observed by the scientists are consistent with the H5 strain of the virus.

The presence of the virus on the nearby French Kerguelen and Crozet islands is not unexpected, as the highly contagious nature of the disease has allowed it to spread rapidly. However, the discovery on Heard Island, which is located more than 2,400 miles southwest of Perth and 1,060 miles north of Antarctica, is particularly concerning. This would be the farthest the flu has reached in the Antarctic region since arriving from South America in 2023.

Heard Island is a breeding ground for large populations of penguins, seals, and seabirds, making the potential spread of the virus to other species on the island a significant worry. Researchers plan to return to the island around the end of the year to assess the situation further.