Bird Flu In Antarctica: What Is H5N1 Strain? How Lethal Is It? Explained

H5N1 has been classified as a highly pathogenic avian influenza (HPAI) virus because of its high death toll in poultry.

Bird Flu In Antarctica: What Is H5N1 Strain? How Lethal Is It? Explained

Antarctica was untouched by bird flu till now.

A lethal strain of bird flu has been detected in Antarctica, a key breeding ground for many birds. The discovery was made by British experts who analysed the unexplained deaths of skuas, a scavenging bird, on Bird Island in South Georgia, a British overseas territory east of South America's tip and north of Antarctica's main landmass. The samples of the birds were sent to the UK and came back positive on October 23, The Telegraph reported. The virus was most likely brought by birds returning from their migration to South America.

What is the H5N1 strain?

It is a sub-type of the avian flu and has been spreading across the world. According to US government's National Library of Medicine, the first outbreak of H5N1 avian flu in humans occurred in 1997 in Hong Kong.

The current outbreak has been caused by a deadly form of the H5N1 sub-type, said Nature. The strain emerged in Europe in 2020, and has spread fast to a number of countries, including South America, where there has been a huge number of bird flu cases.

H5N1 has been classified as a highly pathogenic avian influenza (HPAI) virus because of its high death toll in poultry. Outbreaks are usually seasonal, but since 2021, they have become persistent. In 2022, the virus killed millions of birds across five continents, the magazine said.

Will there be a pandemic?

Scientists at Centres for Disease Control (CDC) and other experts have said that it is not easy for the H5N1 virus to transmit from animals to humans. It is even harder for the virus to pass from person to person. 

However, there are concerns that the H5N1 sub-strain may be able to exchange genetic information with the seasonal flu virus if a person with flu develops this bird flu. 

A strain of avian flu virus that develops greater ability to spread among humans could have serious consequences.

Fears of mass wipe-outs

The news about the avian flu virus reaching Antarctica has alarmed researchers across the globe. South Georgia, where the skuas were found dead, is also home to several species of albatrosses, macaroni and gentoo penguins, and northern and southern giant petrels.

Experts fear these birds could also be hit by the disease, which is transmitted mostly through faeces or direct contact.

"Mortality is growing. It's really worrying. Bird Island is one of the most exceptional habitats - the variety and density of birds is astonishing - so it's very concerning that it has arrived in such an important location," Dr Norman Ratcliffe, a seabird ecologist with the British Antarctic Survey, told The Telegraph.

"Some colonies of these birds are very dense, and when it takes hold it can spread quickly," the expert added.

Immunity against H5N1

Antarctica has never had an outbreak of bird flu before so the immunity of its residents is very low. "The populations are completely naive," Dr Thijs Kuiken, a veterinary pathologist at Erasmus University Medical Centre in the Netherlands, told The New York Times (NYT). "The worry is that the first time that it goes through, it will really have a high impact in terms of rate of mortality."

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