Avian Influenza Hits the Antarctic Region for the First Time; Spread of Highly Pathogenic H5N1 Threatens Marine Mammals

Avian influenza, also known as bird flu, has been a major environmental concern in previous years because of its potential to cause severe illness and death in the bird population. After crossing continents, this disease is believed to have reached Antarctica, threatening the remote and fragile ecosystem in the region.

HPAI Alert in Antarctica

In the northern hemisphere, the deadly avian influenza called highly pathogenic avian influenza (HPAI) first started to cause mass mortality outbreaks in seabirds in late 2021. As the bird flu virus arrived in South America last fall, scientists expressed concerns that the outbreak could spread to Antarctica and threaten penguin and seal populations.

It was confirmed on October 22 when scientists detected the virus in brown skua birds on Bird Islands, marking the first virus cases in the Antarctic region. It also raised concerns regarding the potential harm of the flu to penguin and seal populations.

The British Island is about 1,056 miles (1,700 km) off the southern tip of Argentina. It is part of the British overseas territory of South Georgia and the South Sandwich Islands. Argentina also claimed it as part of the Tierra del Fuego Province.

After receiving reports of several potentially symptomatic birds and unexplained mortality in the region, the British Antarctic Survey (BAS) took samples from some birds on the island. The swabs were sent to the UK's Animal and Plant Health Agency, where they tested positive for bird flu. It was not indicated, though, what subtype of the virus has infected the birds.

Natural pathways are the major means of spread of HPAI, and it is also possible that it was caused by the return of birds that migrated to South America, where a high number of HPAI cases was reported.

Two research stations are operated by the BAS in South Georgia, including one on Bird Island. Researchers on the island began to take precautionary measures and suspended most of the field works that involved animal handling. They also conduct enhanced clothing and field equipment cleaning while observing areas of high wildlife density.

How Deadly is HPAI?

The viral disease avian influenza primarily affects bird populations. Low-pathogenic bird flu is common in wild birds and usually causes no signs of disease. However, some viral strains like H5 and H7 are found to be highly pathogenic in domestic poultry and can cause mortality if they escape into wild bird populations. These strains are the ones referred to as highly pathogenic avian influenza.

The current H5N1 HPAI outbreak began in 2022 and resulted in the death of many seabirds in South America, the Pacific Ocean, the Atlantic, South Africa, and the Northern Hemisphere. In this recent outbreak, scientists have reported infection in mammals due to predators and scavengers that consume infected birds or carcasses.

According to the World Health Organization (WHO), the number of cases of bird flu in humans is extremely rare. However, the increasing number of detected H5H1 strains among mammals raises the concern that the virus might also adapt to infect humans more easily.