Bird flu outbreak threatens Antarctic wildlife and research programs

A study has revealed that avian influenza (H5N1) is spreading rapidly in the Antarctic Peninsula, severely affecting wildlife.

Researchers from the Australis expedition announced on the 17th that they confirmed avian influenza infections in nine bird species and four marine mammal species after surveying 27 locations in the Antarctic Peninsula.

Avian influenza is a deadly respiratory disease for birds that has spread globally since October 2021. It has been reported on all continents, including Antarctica, and according to the World Organisation for Animal Health (WOAH), over 280 million birds have died or been culled since October 2021.

Recently, cases of infection in mammals and humans have increased, raising concerns. In the United States, 66 cases of human infection were reported last year, and the first suspected death occurred in January this year. In December 2023, a variant virus spread to the Arctic, causing confirmed deaths of polar bears, raising the possibility that the Antarctic ecosystem could also face a greater threat.

Following the first confirmed H5N1 infection in the Antarctic continent in October 2023, researchers explored 27 locations in the Antarctic Peninsula for six weeks from January this year to investigate further spread. As a result, the H5N1 virus was detected in 24 out of the 27 surveyed locations, confirming infections in a total of 13 species, including nine bird species and four marine mammal species. Additionally, 188 of the 864 samples collected from living animals and carcasses tested positive for the virus.

The animal found with the most carcasses in this survey was the skua. Researchers discovered 172 skua carcasses only in Margarita Bay, located south of the Antarctic Peninsula. They analyzed that the rapid spread of the virus was likely due to the skua's habit of consuming carcasses.

Academics are concerned that the spread of H5N1 could lead to the collapse of the Antarctic ecosystem. There are precedents of H5N1 causing severe damage in other regions. In 2023, 76% of the greater skua population near the United Kingdom decreased due to H5N1, and in the same year, about 18,000 elephant seals in Argentina died en masse.

Researchers noted that although they have not yet confirmed large-scale die-offs in Antarctica, the high concentrations of the virus detected in penguin populations are worrisome. Antarctic animals breed in dense habitats and frequently encounter different species, which greatly increases the risk of virus spread. Furthermore, many species that inhabit Antarctica and its surrounding areas are rare and not found elsewhere in the world, so if infections spread, the risk of extinction rises significantly.

Kim Jung-hoon, a principal investigator at the Korea Polar Research Institute, said, "Mammals inhabiting Antarctica, such as penguins and southern elephant seals, often live in groups, and if H5N1 spreads, mass die-offs could occur."

Although the spread of H5N1 is progressing in earnest, it is difficult to accurately ascertain the actual scale. There are many regions the researchers have not surveyed, making it hard to estimate the overall damage, and in the case of marine mammals, carcasses often disappear in the sea, making it challenging to verify the number of deaths.

Kim expressed concern, stating, "Given the characteristics of Antarctica, the entire process from accurately assessing the number of infected individuals to implementing quarantine measures is difficult. If avian influenza spreads further, there could come a situation where the Antarctic research program itself is halted."

References

Science (2025), DOI: https://doi.org/10.1126/science.z4b7gwj