Highly pathogenic avian influenza (HPAI) H5N1 has been detected in Western Australia, marking the first confirmation of the virus on the continent. The detection occurred after two sick seabirds, a brown skua and a giant petrel found near Esperance, tested positive for the highly contagious strain.
Global Strain Reaches Australia
The confirmed strain is HPAI H5N1 clade 2.3.4.4b, a globally circulating variant that has spread rapidly over the past five years, causing significant losses in poultry and wildlife populations worldwide. Prior to these detections, Australia was the last continent to remain free of this particular strain of bird flu. The virus has been confirmed in millions of wild animals and poultry across other continents and has also spilled over into mammals, including dairy cattle, seals, and sea lions.
This strain presents a different challenge compared to previous bird flu outbreaks in Australia, as it can infect a wider variety of species and spreads more quickly, including between mammals and across continents. Transmission typically occurs through close contact with infected animals or contaminated environments, such as scavenging carcasses. Species living in large colonies and scavengers are considered particularly vulnerable.
Origin and Potential Spread
The presence of the virus in Southern Ocean seabirds suggests it likely arrived in Australia via wildlife movements rather than through migratory shorebird routes. Research indicates that migratory wildlife, including seabirds, have been instrumental in spreading this virus across the Southern Ocean from South America since 2023. Genetic sequencing will be crucial to determine the precise relationship between the virus found in Australian birds and strains detected elsewhere.
While the current risk to humans from H5N1 is considered low, human infections are rare and usually involve direct or indirect exposure to infected animals or contaminated environments. In the United States, this virus has severely impacted poultry and dairy industries, leading to mass culling of commercial flocks. At present, no H5N1 cases have been identified on Australian poultry or dairy farms, but producers are being advised to adhere to strict biosecurity measures, including minimizing contact between domestic and wild birds and protecting feed and water sources.
Preparedness and Response
Australia has been preparing for a potential H5N1 outbreak since 2024, with a national taskforce jointly led by the National Emergency Management Agency and federal agriculture, environment, and health departments. This taskforce has conducted outbreak exercises and enhanced surveillance efforts.
The response now shifts to action, with plans to expand surveillance around seabirds, wetlands, scavengers, marine mammals, and both backyard and commercial poultry. Rapid sequencing of positive samples is a priority to map the virus’s potential spread. Wildlife managers are urged to develop plans for vulnerable populations, and consideration may be given to vaccination options for highly susceptible wildlife, similar to trials underway in the United States for seals.
The public is encouraged to report any sightings of sick or dead birds or marine mammals to the Emergency Animal Disease Hotline on 1800 675 888, noting the location and taking photos from a safe distance. Authorities also advise the public to avoid touching sick or dead animals and to keep pets away from carcasses.
Helene Elliott is the senior reporter for News Raise. She covers Science news. She also has a keen interest in photojournalism. Helene holds a nomination for the prestigious Red Smith Award. She is married to author Dennis D’Agostino, a former publicist with the New York Mets.
