TEMPO.CO, Jakarta - Australian authorities have warned that more mass bird deaths are likely after the country confirmed its first large-scale wildlife mortality event caused by the highly pathogenic H5 avian influenza virus, commonly known as bird flu, marking what officials described as the beginning of a prolonged environmental crisis.
The outbreak was confirmed after dozens of greater crested terns and silver gulls died at Baudin Rocks, off Cape Jaffa in South Australia, becoming Australia's first recorded mass mortality event linked to the H5 strain of bird flu.
Agriculture Minister Julie Collins said the virus could continue affecting Australia's wildlife for years despite extensive preparedness efforts.
"This could be a long period of time and a very long journey," Collins said, noting that countries overseas have been battling the same strain since 2022.
According to news.com.au, Collins said Australia had done everything possible to delay the virus' arrival, but acknowledged it was impossible to stop such a highly contagious disease from spreading among wild birds.
"We've certainly seen devastating impacts overseas, particularly mass bird mortalities," she said. "We cannot stop a very virulent, very contagious disease in wild birds."
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) has so far confirmed 74 H5 bird flu cases nationwide, with detections reported across South Australia, Victoria, Western Australia, New South Wales, and Queensland.
Environment Minister Murray Watt issued an equally stark warning, saying Australians should prepare for further wildlife losses.
"I want to level with people: this is the beginning of what is likely to be a long, difficult journey in terms of the impacts on wildlife," Watt said.
He said Australia had been the last continent to record the arrival of this particular H5 strain, allowing authorities additional time to prepare. However, once the virus entered migratory bird populations, preventing further spread became virtually impossible.
"The reality is, you can't stop native and wild birds flying around, and you can't stop wild animals moving around," Watt said. "That will mean more mass mortality events like the one we have now seen."
Authorities said aerial surveillance over Baudin Rocks detected about 50 dead birds and another 30 showing signs of illness. Laboratory testing later confirmed H5 infection in five greater crested terns and one silver gull.
As reported by The Guardian, concerns have already expanded beyond South Australia after aerial surveillance identified another cluster of sick and dead greater crested terns in Victoria's Glenelg River estuary near Nelson and at nearby Lawrence Rocks.
Victorian authorities are awaiting laboratory confirmation, but officials said field observations closely resemble the South Australian outbreak. If confirmed, it would become Australia's second documented mass mortality event linked to the virus.
Victorian Chief Biodiversity Officer James Todd said surveillance findings were consistent with the recent outbreak across the border.
State Chief Veterinary Officer Graeme Cooke also reported a clear increase in dead seabirds along Victoria's southwest coastline during recent inspections.
Beyond South Australia's initial outbreak, authorities have confirmed 18 additional H5 cases across several new locations, including Pages Islands, Troubridge Island, Southend, Glenelg, Monarto, and the internationally significant Coorong wetlands.
The detection of the virus in a migratory petrel at the Coorong has heightened concerns because the wetland supports large populations of native waterbirds and migratory species.
South Australian Environment Minister Emily Bourke said the expanding geographic spread demonstrates how quickly the virus is moving beyond seabird colonies.
The Australian government said eradication is no longer considered feasible and efforts will instead focus on monitoring outbreaks, protecting vulnerable wildlife populations where possible, and strengthening surveillance across affected regions.
Officials also warned the virus has the potential to infect some mammal species, although current infections in Australia remain primarily confined to wild birds.
"This is not something that will disappear quickly," Collins said. "Australians should expect further spread and larger numbers of wildlife to be affected."
Read: South Australia Reports 7 New Suspected H5N1 Bird Flu Cases
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