Australia remains on high alert for killer bird flu despite enduring recent high-risk migration season
The H5N1 strain of high pathogenicity avian influenza (HPAI), commonly known simply as bird flu, was first detected in Hong Kong in 1997 but seemed to subside until it reappeared in Asia in 2003. It soon spread rapidly through bird populations across the Middle East, the Americas, Europe and Africa.
The disease has caused the deaths of millions of birds – wild, farmed and pet. The same disease has also spread to marine mammals, killing tens of thousands of elephant seals, sea lions, dolphins and even otters. In early 2024, H5N1 reached mainland Antarctica, devastating populations of penguins and other bird species and seals.
This global spread has significantly impacted commercial poultry flocks and devastated agricultural industries. On rare occasions, humans have also been infected.
Australia emerges unscathed from recent migration season
For decades, Australian authorities have been bracing for the arrival of H5N1, and conservationists have long been dreading the day it arrives. Yet Australia remains the only continent free of the virus.
Recently, the country dodged another bullet, enduring last spring’s high-risk global bird migration season.
Wildlife Health Australia (WHA) was allocated $7 million from the federal government’s $95 million H5N1 funding commitment, which was made in October last year to prepare for the arrival of the virus.
WHA works with partners to identify emerging wildlife diseases and oversee the management of outbreaks. It has coordinated the national avian influenza wild bird surveillance program for almost 20 years.
Dr Tiggy Grillo, chief operating officer at WHA, says one reason H5N1 didn’t make it to our shores during the most recent high-risk season was because the severity of the virus either killed or prevented many infected birds from making their annual migration.
“For some species that get infected they might die where they are in that other country. Some birds can be exposed and survive, but they still might not be well enough to travel,” she explains.
“We know some birds do get exposed, but they mount an immune response, have survived, and have come to Australia. But we haven’t seen any active infection. We are still learning about what birds can move with this virus and stay healthy enough to reach Australia.”
‘We can’t stop the virus’
Despite withstanding this most recent threat, wildlife authorities are warning the virus continues to pose a significant threat, with its arrival still a matter of ‘when’, not ‘if’.
“We can’t stop the virus coming to Australia,” Tiggy says.
“This virus that is being seen overseas is unlike any previous avian influenza virus. This particular virus will have significant impacts on our unique wildlife, our agricultural industries and our economy.”
Before the federal government’s funding announcement last October, the Invasive Species Council, a non-government conservation advocacy organisation, had been vocal in calling for a larger, coordinated response from authorities.
Jack Gough, the Council’s acting CEO, says he is pleased with how government departments are mobilising to prepare for the arrival of the virus. However, he warns there’s no room for complacency.
“We’re not out of the woods and won’t be out of the woods for years to come,” Jack says. “We’ve been essentially protected by distance, but that means we’re also at high risk because there’s no built-up wildlife immunity. It’s highly likely we’ll see this disease turn up…and it won’t be something that’s eradicable.”
Three potential virus pathways
Three potential pathways for H5N1 to enter Australia have been identified, says Tiggy: the long-distance annual migration of birds from countries around the world already infected with H5N1, the movement of ducks and other waterfowl between Australia and countries to our north, and animals coming to Australia from Antarctica.
1. Global migration of infected birds
Tiggy says that while the annual spring migration has now finished, “the threat of this particular bird flu arriving in Australia is actually year-round”.
“It’s certainly a higher risk during the spring season because there are millions of birds that come to Australia during that period from areas where the virus is circulating,” she says. “But it is not the only risk period.”
2. Movement of waterfowl between Australia and countries to our north
“The second plausible pathway is through nomadic waterfowl movement, and that movement is very different from the long-distance migratory birds,” she says.
“Those nomadic waterfowl in Australia that move to the countries just to our north move frequently yet irregularly, and there is no pattern. So if the virus was to move within the Asia-Pacific region towards the countries just to our north, then the risk certainly does change to Australia.”
3. Animals coming to Australia from Antarctica
“The third plausible pathway [is] through Antarctica. We’re watching that very, very closely,” she says.
Vaccination calls
Experts are urgently exploring options for vaccinating threatened bird species as one way of preparing for H5N1’s arrival.
“We know there are things that can be done to limit the impact that it has, particularly on some of our species that are on the brink of extinction,” Jack says.
“The sorts of things that can be done include looking at vaccination of captive-bred populations of birds like swift parrots or orange-bellied parrots and looking at vaccination of some of the at-risk wild populations…like, potentially, sea lions on Kangaroo Island.
“The United States has been vaccinating condors. New Zealand has started vaccination of ground-nesting birds. South Africa has been vaccinating some of their penguins.
“When [H5N1] turns up, it will be devastating. It’s about minimising those deaths and maximising the resilience of highly vulnerable native animals and bird populations so they can make it through that initial wave of the virus and don’t go extinct.”
A spokesperson for the Australian Department of Climate Change, Energy, the Environment and Water (DCCEEW) says it’s collaborating with the Department of Agriculture, Fisheries and Forestry to work through regulatory and policy arrangements for the potential vaccination of threatened bird species.
“The decision of whether to vaccinate and how to apply vaccination to domestic, captive or threatened wild birds is complex and will depend on many factors,” the spokesperson says.
A broader response
Conservation organisation BirdLife Australia is also backing moves towards vaccination but says it must be part of a broader response.
“The healthier bird populations are, the more resilient they are,” says Tanya Loos, avian influenza response coordinator at BirdLife Australia.
“We were asking for vaccination trials, and we’re not ruling it out for some of our most threatened species like the orange-bellied parrot. But it’s very much part of a whole integrated response rather than something we’re emphasising more than anything else. We feel there are so many steps that need to be taken before that, [such as] comprehensive surveillance and monitoring, and really swift action on behalf of all the authorities to respond. [This includes] making sure that land managers have really good training.”
The DCCEEW spokesperson says the federal government is “undertaking a H5 bird flu susceptibility analysis for all native bird and mammal species”.
Meanwhile, Tanya emphasises that if the virus does enter Australia, it will also pose a serious risk to birds not currently considered endangered.
“It’s not just threatened species that we’re worried about,” she says. “We’re also worried about so-called common species such as black swans. But obviously we wouldn’t be looking to do vaccination for all the black swans across Australia. What we would be looking at is how we reduce stress in black swan populations and how we mitigate the spread if there’s an incursion.
“So many Australian bird species are [already] under threat from things like habitat destruction, introduced or feral species, and ongoing effects of climate change such as heatwaves and bushfires.
“A healthy population is more able to respond to a disease outbreak – even something as virulent and shocking as this particular form of avian influenza.”
Avoid, record, report
Tiggy says the public has an important role to play in the months ahead.
“We’re really keen for people to be aware of avian influenza and to promote that mantra of avoiding – so not touching – the birds or the wildlife that you see dead, [and instead] recording what you see and then reporting it to the Emergency Animal Disease Hotline,” she says.
“A false alarm is better than not reporting because the earlier we detect an unusual disease event that could be caused by this strain of avian influenza, the much earlier we can respond and stop the disease spreading.”
The Emergency Animal Disease Hotline can be contacted on 1800 675 888.
