Antarctica wildlife at risk as bird flu surges around the globe

As the sun dipped low on the horizon, casting long shadows over the rugged Canadian coastline, a team of scientists ventured into the heart of a seabird breeding colony. The surroundings echoed with the cacophony of seabird calls, a symphony of life that reverberated through the coastal air. Yet, amidst the lively chorus, the scientists felt something was wrong.

They pressed forward, their footsteps muffled by the soft blanket of moss beneath their boots, until they came across what they had come here for – bodies, scattered across the rocky shores, their lifeless forms a stark contrast to the beauty that surrounded them. The scientists moved with purpose, their trained eyes scanning the landscape for clues amidst the chaos. With measured steps, they approached each fallen bird, their gloved hands gentle as they collected samples for analysis.

The cause of death? A Highly Pathogenic Avian Influenza (HPAI) virus known as H5N1.

HPAI viruses are distinguished by their high pathogenicity, causing severe systemic infections and rapid death in susceptible bird species. The severity of illness can vary depending on factors such as the virus subtype, the host species, and environmental conditions. The primary mode of transmission among birds is through direct contact with respiratory secretions or faeces from infected birds.

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Wild migratory birds, especially waterfowl, serve as natural reservoirs for these viruses, playing a crucial role in their spread over vast geographic regions. This means that the viruses are a global concern due to their ability to spread rapidly across continents through migratory bird pathways and international trade.

H5N1 now presents an existential threat to the world’s biodiversity.

Dr. Chris Walzer

Even more worrisome is the transmission of HPAI viruses from birds to mammal populations. From January 20 to July 31, 2022, researchers collected nasal, oral, conjunctival, and rectal swab samples from 132 stranded seals spanning the coastal stretch from Maine to Virginia along the US northeast shoreline. Initially, hope flickered as no traces of the HPAI virus were found among the first 82 seals sampled until May 31, 2022.

The National Oceanic and Atmospheric Administration (NOAA) sounded the alarm on June 1, 2022, declaring an Unusual Mortality Event (known as “UME”) that killed 164 harbor seals and 11 gray seals in Maine alone. As researchers delved deeper, they uncovered a startling revelation: out of 41 sampled seals, 17 harbor seals and 2 gray seals were HPAI positive, clustered within coastal regions already besieged by outbreaks among terns, eiders, cormorants, and gulls. Amidst the tragedy, a subset of the stricken seals exhibited respiratory symptoms and neurological complications; nasal, oral, conjunctival, and rectal samples confirmed the virus.

It’s not only the seals in New England that have been impacted. H5N1 has ravaged Peru’s pelicans, boobies, sanderlings, and Guanay cormorants (with numbers of at least 63,000) and the Peruvian population of about 105,000 South American sea lions (Otaria flavescens), killing more than 3.29% of the total population.

“The fact that the virus is not only in birds but also in mammals means it is potentially risky for the public,” says Sefor biologist Pilar Ayala, who is among a team of wildlife specialists dedicated to registering and collecting samples from deceased and ailing animals along Peru’s extensive Pacific coastline. “It is currently being seen in different species of mammals, so we must take precautions in order to avoid another pandemic for humans.”

Although human infections are rare, they can result in severe respiratory illness and, in some cases, death. Close contact with infected birds or contaminated environments is the primary route of transmission to humans, and infection by the H5N1 virus has already occurred in countries like Chile and Ecuador.

Today, cases of avian flu in polar bears, otters, foxes and seals have been recorded in other countries 

From 2003 to July 2023, the World Health Organization (WHO)  documented 878 cases of HPAI H5N1 infection in humans and 458 (52.16%) fatalities in 23 countries.

The initial outbreak of the HPAI H5N1 virus occurred in 1959 among poultry in Scotland. Yet by the 1990’s the HPAI H5N1 virus had travelled across the Northern Hemisphere, where it made to Hong Kong and caused the deaths of six individuals out of the 18 who contracted the infection in 1997. This marked the first identification of an HPAI H5N1 virus strain affecting humans, gaining global attention.

After a brief lull, the HPAI H5N1 virus resurged in 2003 and has since persisted, spreading among wild avian populations across Europe, Asia, and Africa.  Today, cases of avian flu in polar bears, otters, foxes and seals have been recorded in other countries, including the UK with approximately 70 mammals confirmed positive for the H5N1 virus.

Finland has recently disclosed another H5N1 outbreak at a fur farm, impacting a facility that houses blue foxes; this occurrence brings the total number of outbreaks at such farms to 25. H5N1 has also been found in domestic cats, tigers, leopards, grizzly bears, and frighteningly in very mobile marine mammals like dolphins and porpoises.

“H5N1 now presents an existential threat to the world’s biodiversity. It has infected over 150 wild and domestic avian species around the globe as well as a dozens of mammalian species,” says Dr. Chris Walzer, Wildlife Conservation Society Executive Director of Health.

“Globally, HPAI H5N1 has now infected many mammals—including foxes, pumas, skunks, and both black and brown bears in North America. Some 700 endangered Caspian seals died from HPAI near Dagestan in 2023. Additionally, outbreaks in mink farms in Spain and Finland that serve as potential mixing vessels for reassortment have also been documented. HPAI H5N1 in Latin America [has had] devastating consequences.”

The H5N1 virus has not yet infiltrated Australia and New Zealand, but in October 2023, H5N1 was confirmed by British scientists for the first time in the Antarctic region.  The virus was detected during the sampling of ill and deceased brown skuas discovered on Bird Island, located off the coast of South Georgia.

Since H5N1 arrived in the Antarctic, there have been mass deaths of elephant seals as well as increased deaths of fur seals, kelp gulls and penguins, according to the latest update from the Scientific Committee on Antarctic Research (Scar). “If the virus does start to cause mass mortality events across penguin colonies, it could signal one of the largest ecological disasters of modern times,” researchers wrote in a pre-print research paper.

The Scientific Committee on Antarctic Research agreed: “Given the dense breeding colonies of wildlife in the Antarctic and sub-Antarctic regions, HPAI is expected to have devastating impacts on the wildlife and to lead to catastrophic breeding failure and mortality events in the region.”

Some believe it is a matter of time before it reaches our shores. “This [new bird flu strain] has not been detected in Australia, but there are concerns about the potential impacts on poultry and wildlife if it arrives on our shores,” the Australian Government’s Department of Agriculture and Fisheries website states. While there is hope strict biosecurity measures will help protect against the disease in regard to the poultry industry, it doesn’t address the biggest concern: wild bird species, particularly waterfowl and shorebirds, could serve as carriers of the virus, facilitating its spread across different regions.

One solution to this problem is increasing monitoring of wild bird populations, but that is easier said than done according to Professor Michael Ward from the Sydney School of Veterinary Science. “One of the problems is implementing surveillance of animal viruses, it’s always difficult to sample wild populations, particularly birds,” Ward says.

But Walzer thinks it should be one of the top priorities for countries worldwide. “The cost of inaction is already causing major devastation to wildlife. As we work to help affected populations recover, we must remain vigilant against the spread of this deadly pathogen to people before it’s too late.”