Australian black swan genomic sequencing reveals the iconic birds could be decimated by avian flu

For the first time, the iconic Australian black swan’s genome has been sequenced, but the results have scientists concerned about the potential catastrophic impact on the species by viral infections such as avian flu.

The study, led by University of Queensland (UQ) researchers, reveals the species lacks genes which help other wild waterfowl produce an immune response to fight infectious diseases.

Black swans live throughout Australia, except the Cape York Peninsula. They are found in higher numbers in the south of the country. Though endemic to Australia, the large waterbirds do occasionally visit Papua New Guinea, and have been introduced to New Zealand, other neighbouring countries, and even Japan.

International Union for Conservation of Nature (IUCN) criteria place the black swan in the “Least Concern” category. Its numbers are estimated to be between 100,000 and one million.

Despite its strong population, scientists are warning of the potential devastation that avian influenza could wreak on the black swan.

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UQ associate professor, Kirsty Short, says the bird’s geographic isolation has meant limited exposure to pathogens common in other parts of the world.

“Unlike Mallard ducks for example, black swans are extremely sensitive to highly pathogenic avian influenza (HPAI, often referred to as bird flu) and can die from it within three days,” says Short. “Our data suggests that the immune system of the black swan is such that, should any avian viral infection become established in its native habitat, their survival would be in peril.”

Avian influenza was first detected among domestic waterfowl in southern China in 1996. The virus spreads naturally among aquatic birds in the wild and can infect other birds and animals, including domestic poultry. While it doesn’t normally afflict humans, sporadic human infections can occur.

A seemingly highly-infectious and deadly strain of bird flu has been rampaging through Europe and the United States since late 2021. The wave is the worst ever in these areas.

In the US, 58 million poultry were affected as of this month. Europe saw outbreaks on around 2,500 farms across 37 countries. 50 million birds have been culled across the continent.

While HPAI isn’t currently in transmission in Australia, the country’s iconic black swans would be in serious danger should the virus make its way onto our shores.

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“We currently don’t have HPAI in Australia, but it has spread from Asia to North America, Europe, North Africa and South America. When it was introduced to new locations, such as Chile and Peru, thousands of wild seabirds perished. The risk to one of Australia’s most unique and beautiful birds is very real, and we need to be prepared if we hope to protect it,” Short explains.

Short hopes better understanding will help protect not only the black swan, but other susceptible species worldwide as well.

“We want to increase awareness about how vulnerable Australia’s bird species are to avian influenza and the highly precarious situation they are in,” Short says.

The research is published in Genome Biology.