Australia has confirmed its first mass mortality event in native wildlife caused by the H5N1 bird-flu virus.
The event marks a significant escalation in the virus's impact on the region's biodiversity. Officials said this development could lead to wider outbreaks across various wildlife populations and potentially threaten agricultural sectors.
The deaths occurred on Baudin Rock, an island off South Australia's south-east coast near Cape Jaffa and the mouth of the Murray River [2, 3, 4]. The virus primarily impacted greater crested terns, which are native seabirds [1, 2].
While initial investigations reported more than 80 birds found dead or sick [5], official confirmation later listed 78 cases [1]. Other reports indicated that 84 terns were killed at the site [3]. The discrepancy reflects the challenges of counting casualties in remote colony environments.
Agriculture Minister Julie Collins said the situation is a serious concern for the country's wildlife. The virus is highly pathogenic and spreads rapidly through dense seabird colonies [4]. There are further concerns that silver gulls may act as vectors, potentially carrying the H5N1 virus further inland [3].
“Australians can expect to see greater disease spread, with larger numbers of wildlife impacted,” Collins said [1].
Testing for the mass mortality event began on Aug. 1, and the government confirmed the results on Monday [1, 5]. The discovery follows a pattern of avian influenza outbreaks seen globally, but this is the first time Australia has witnessed a mass death event in its native wildlife linked to the H5 strain.
“Australia has confirmed its first mass mortality event in native wildlife caused by the H5N1 bird-flu virus.”
The transition from sporadic individual cases to a mass mortality event indicates that H5N1 has established a foothold in Australian seabird populations. Because the virus can be transported by mobile species like gulls, the risk of the pathogen moving from coastal isolates to inland poultry farms or other vulnerable wildlife increases significantly, necessitating heightened biosafety surveillance.
