Imma Perfetto
Cosmos science journalist
Discovery of how the deadly avian influenza virus spread to the Antarctic has raised concerns about how vulnerable the region will be during seabird breeding season.
In October 2023, British researchers confirmed for the first time the presence of highly pathogenic avian influenza (HPAI) in the Antarctic and sub-Antarctic regions.
The strain detected in remote South Georgia and the Falkland Islands was HPAI H5N1 clade 2.3.4.4b, the virus responsible for the global animal pandemic that has caused the death and destructions of millions of wild and domestic animals.
The initial viral genome sequences were made freely available months ago. Now, a full documentation of the extensive field sampling and diagnostic testing, published in Nature Communications, has revealed the virus spread from South America, likely through migratory wild birds.
The study details the virus’ initial detection in brown skuas in South Georgia inside the Antarctic region, followed by its rapid spread across multiple avian species and 2 seal species. It was simultaneously detected in southern fulmar and black-browed albatross in the Falkland Islands archipelago 1,500km to the west.
Dr Jane Younger, a lecturer in Southern Ocean vertebrate ecology at University of Tasmania in Australia, who was not involved in the research, says HPAI in the Antarctic and sub-Antarctic regions is an alarming development, underscoring the vulnerability of these remote ecosystems to infectious diseases.
“The recent study … provides critical insight into how migratory birds may act as vectors for the virus to enter new regions,” says Younger.
“In this case, the virus most likely spread to South Georgia and the Falklands from South America, where infections have killed tens of thousands of seabirds and marine mammals. This raises significant concerns about the potential spread of the virus to other areas of Antarctica, especially during the upcoming Antarctic seabird breeding season.
“This heightens fears that the virus could spread to more isolated regions via migrating birds and mammals.”
Confirmed and suspected cases of HPAI in the Antarctic and sub-Antarctic are reported through the Scientific Committee on Antarctic Research (SCAR).
Dr Michelle Wille, of the Centre for Pathogen Genomics at the University of Melbourne, Australia who was not involved in the research, says the last reported case in the Antarctic region was in March 2024, at the end of the tourist and research season.
“This article is extremely timely, given that research teams (and tourists) will soon be returning to the Antarctic region for the austral summer season,” says Wille.
“The data provides critical insights into virus introduction and spread, which will be integrated into continued and future preparation and response activities in Antarctica.”
Crucially, genome analysis reveals no evidence yet of virus transmission between infected marine mammals.
“Given the concern around potential mammal-to-mammal transmission in marine mammals in South America, it is encouraging that the full genome sequences from elephant seals and a fur seal did not contain any PB2 mutations of interest,” says Wille.
Dr Vinod Balasubramaniam, a molecular virologist at Monash University Malaysia, who was not involved in the research, adds: “The study did not find any unique adaptive mutations in the Antarctic strains that would increase the risk to human populations compared to other global instances of H5N1 infections.
“This finding is crucial because H5N1 is known for its potential to cause severe disease in humans, and mutations that increase transmissibility or virulence could pose significant public health risks. Monitoring the genetic composition of the virus is essential to detect any changes that might enhance its threat to humans or wildlife.”
