A highly contagious form of bird flu has been confirmed in Antarctic seals for the first time, threatening one of the most fragile ecosystems on the planet.
Scientists working for the UK's Animal and Plant Health Agency (APHA) have discovered the H5N1 virus variant in samples taken from dead elephants and fur seals on the sub-Antarctic island of South Georgia.
Dozens of animals are known to have died, many likely in remote bays and at sea.
Experts at the British Antarctic Survey told Sky News that the unfolding tragedy was a “mass mortality event.”
Dr Marco Valchieri, from APHA, spent three weeks collecting wildlife samples in South Georgia, a UK overseas territory in the Southern Ocean.
Photo: Abha
Seals and seabirds share the same beaches, giving the virus an opportunity to transmit, he said.
“It's important because this level of mortality is not typically seen in this population,” he said.
“The fact that we found the virus suggests that it is responsible for the victims seen.”
The virus has swept the globe
Figure 2.3.4.4b of the virus has swept the globe, spreading by migratory birds. It has caused mass die-offs in several seabird colonies in the United Kingdom.
Any movement of the virus between birds and mammals is a concern for scientists, who are closely monitoring “spillover events” for any sign of mutation.
It is believed to have killed thousands of seals across South America, as well as large numbers of mink and foxes that are farmed for fur in Europe. It has been discovered in a small number of mammals in the UK, including seals and wild foxes.
But there is no good evidence that the virus spreads between mammals, and APHA scientists found no indication that the virus has adapted to survive in seals.
“These animals share the same environment as birds,” Dr. Valchere said.
Read more:
The third set of vaccines is for duck foie gras to try to stop the bird flu outbreak
Hope in the fight against deadly bird flu
Nearly 10,000 seabirds died and fell ill across Scotland
“This is how we think these animals contracted the virus.”
Conservationists had hoped that the vast Southern Ocean would prevent the virus from arriving Antarctica and South Georgia, but was discovered in October in the carcasses of brown skua, a large seabird.
'Big relief' for penguins in Antarctica at the moment
New research by APHA has also found the virus in kelp gulls and Antarctic terns, but so far it has not been seen in penguins.
Professor Ashley Banyard, a bird flu specialist at APHA, told Sky News: “It is a relief for many of us that penguins have not been affected.”
Curious penguins examine Dr. Valchere. Photo: Abha
“We don't know whether this is due to a lack of susceptibility, or whether they had prior exposure and some antibody response to a less pathogenic virus that may have been transmitted asymptomatically in migratory birds.”
But penguins have been affected in other parts of the world and wildlife experts fear the consequences of the virus reaching Antarctica itself.
“These are mass mortality events well above baseline levels,” said Norman Ratcliffe, a seabird ecologist at the British Antarctic Survey.
“If the virus becomes established on the continent, it will likely spread throughout it.
Photo: Abha
“This will impact the global population of emperor penguins and a very large proportion of the world's Adelie penguins as well.
“It is also possible that leopard seals, crabs and Weddell seals are infected.
“These are all species that are found nowhere else, so this will have global implications for Antarctic wildlife.”
Many Antarctic species are already struggling with climate change and declining sea ice.
