What Happened
Australia is facing a sharp escalation in its highly pathogenic avian influenza (H5) outbreak, marked by the confirmed deaths of more than 1,000 greater crested terns. These carcasses were discovered on three critical breeding sites off the coast of South Australia: Troubridge Island, North Page Island, and South Page Island. State government surveillance teams identified these mass mortality events as a significant shift in the virus’s behaviour, noting that it is now killing birds within densely packed colonies rather than isolated individuals.
The scale of the loss on these remote islands has prompted urgent responses from state leadership. South Australian Premier Peter Malinauskas addressed the situation in parliament, describing the verified deaths as “deeply concerning” and confirming that authorities are treating the events with the utmost seriousness. While the confirmed toll stands at over 1,000 birds across the three sites, officials caution that the actual death toll may be higher because not every carcass can be retrieved or tested.
The Timeline
The current wave of detections began with federal data released on 6 August, which listed 123 positive or presumed-positive findings across the nation. By Friday, 14 August, South Australia alone had recorded 177 confirmed cases, indicating a rapid acceleration in transmission rates within the state.
The specific mass mortality events involving the greater crested terns were detected on Wednesday, 19 August 2026. This discovery followed earlier detections of the virus in coastal areas near Adelaide, on Kangaroo Island, and along the Limestone Coast. The outbreak has since spread beyond South Australia, with H5 identified in wild birds in Victoria, Western Australia, and New South Wales.
The geographic scope of the infection is widening as investigations continue into other species. Seven of the state’s 11 confirmed deaths have occurred on King Island. Furthermore, investigations are currently underway in Tasmania and South Australia regarding deaths involving little penguins. In Tasmania specifically, the virus was found for the first time last Thursday, 20 August 2026, in a brown skua at Rocky Cape on the north-west coast, followed by subsequent findings of dead silver gulls and crested terns.
Who Said What
South Australian Premier Peter Malinauskas stated that no similar mortality events had been reported in mammals within Australia. However, he noted that international experience shows some mammalian species can become infected after contact with sick birds. Despite the surge among wild bird populations, officials confirmed that no H5 infections have been verified in domestic poultry or the broader agricultural sector.
Consequently, Australia continues to be recognised as free of highly pathogenic avian influenza in its poultry industry according to international animal-health guidelines. Health officials maintain that the likelihood of human infection is minimal, noting that cases in people are rare and usually involve close contact with sick birds or heavily contaminated environments.
Why This Matters
The situation poses a unique threat to native wildlife due to the biology of the affected species. Greater crested terns remain in Australia year-round and form large nesting aggregations, creating ideal conditions for rapid viral spread. The virus is not confined to seabirds; a raven recovered from the Limestone Coast tested positive, demonstrating that the pathogen can affect other coastal fauna.
While no H5 cases have been reported in Australian mammals, producers and backyard-flock owners are being urged to tighten biosecurity measures. This includes keeping domestic birds away from wild birds, feathers, droppings, or contaminated water sources to prevent cross-species transmission.
For the public, the primary advice remains to avoid handling sick or dead birds. Anyone who discovers multiple ill or dead birds should stay clear of the area, note the location, and report the incident to the Emergency Animal Disease Hotline on 1800 675 888. Carcasses should not be moved or disposed of unless directed by authorities. Proper handling and thorough cooking ensure that chicken meat and eggs remain safe for consumers, as the virus is not regarded as a food-safety hazard when poultry products are prepared correctly.
Each suspected case still requires laboratory confirmation; not every dead bird is automatically counted as H5-related. Official guidance and updates continue to be issued by the Department of Agriculture, Fisheries and Forestry as surveillance teams work to contain the spread.