On a remote beach near Esperance, Western Australia, two sick seabirds have brought the bird flu crisis to Australia.
Testing has confirmed highly pathogenic avian influenza (HPAI) H5N1 in a brown skua and a giant petrel. Both are species of seabirds commonly found in the Southern Ocean.
H5N1 is a type of avian influenza, or bird flu, caused by an influenza A virus. The strain has been confirmed as HPAI H5N1 clade 2.3.4.4b, a globally circulating strain that can spread rapidly. Over the past five years, this strain of the virus has killed millions of wild animals and poultry.
These are the first confirmed detections of this strain in Australia. But the coming weeks will tell us whether these are isolated cases, or the start of a wider outbreak.
Spreading far and wide
Since 2021, the HPAI H5N1 strain of bird flu has spread through every continent except Australia. Overseas, it has devastated wildlife and caused major losses in poultry. This strain has also repeatedly spilled over into mammals including dairy cattle, seals and sea lions.
This strain of H5N1 is a different challenge to the bird flu outbreaks Australia has seen before. That’s because this strain can infect a much wider variety of species and spreads more quickly than other strains, including between mammals and across continents.
Transmission occurs through close contact with infected animals or contaminated environments, including scavenging of carcasses. This is why birds living in large colonies such as gannets, terns and albatrosses are most vulnerable. Tasmanian devils and other scavengers are also more exposed to the virus.
For humans, the current risk is low. Human infections are rare and most cases involve direct or indirect exposure to infected animals or contaminated environments. Examples include dairy farms, live poultry markets or beaches with sick or dying wild birds and marine mammals.
How did it get to Australia?
The species of the two confirmed bird flu cases are the first clue to how the virus reached our shores. Brown skuas and giant petrels are Southern Ocean seabirds who fly across huge distances and may scavenge contaminated carcasses.
Their detection in Western Australia suggests the virus likely reached mainland Australia through Southern Ocean wildlife movements, rather than the northern migratory shorebird routes.
Our research shows migratory wildlife, including seabirds, have spread this virus thousands of kilometres across the Southern Ocean from South America since 2023.
Genetic sequencing of the virus will be essential to show how closely the virus in these birds is related to viruses from Heard Island, Antarctica, South America or elsewhere.
A devastating disease
In the United States, this virus has decimated the country’s poultry and dairy industries. It has led to the mass culling of commercial flocks, both to contain the virus and prevent price hikes for consumers.
At this stage, no H5N1 cases have been detected on Australian poultry or dairy farms. However, poultry producers now must follow government guidance on maintaining biosecurity standards. This involves minimising contact between domestic birds and wild birds, protecting feed and water sources and immediately reporting unusual illness or deaths.
Also at risk are Australian fur seals and colony nesting seabirds such as terns, gannets, and albatrosses. Tasmania’s endemic shy albatross and culturally significant yula, or short-tailed shearwater, are also vulnerable to the virus.
Freshwater birds such as ducks are another concern, as they can spread influenza viruses through water. For critically endangered birds such as orange-bellied parrots, even a few bird flu deaths can put the entire species at risk.
So, what can we do?
Given Australia was the last H5N1-free continent, we’ve had time to prepare.
Since 2024, a dedicated national taskforce has led the country’s response to a potential H5N1 outbreak. This taskforce – jointly led by the National Emergency Management Agency and the federal agriculture, environment and health departments – has conducted outbreak exercises and increased surveillance across Australia.
This preparation must now become action. Surveillance should expand around seabirds, wetlands, scavengers, marine mammals, backyard poultry and commercial poultry. Positive samples should be sequenced quickly to map how the virus may spread. Wildlife managers need plans for vulnerable wildlife populations before they get exposed.
Beyond surveillance, there are other tools we can use. In the United States, researchers are trialling bird flu vaccination in seals as a way to protect endangered Hawaiian monk seals. If our outbreak worsens, Australia should consider similar options for highly vulnerable wildlife, such as fur seals, black swans and other native birds.
The public can help authorities contain the spread of H5N1 by reporting any sick or dead birds or marine mammals to the Emergency Animal Disease Hotline on 1800 675 888. It’s best to note the location and share any photos taken from a safe distance. The public should also avoid touching sick or dead animals, and keep dogs away from any carcasses.
