H5N1 Bird Flu Reaches Victoria as Local Transmission Confirmed in South Australia

The deadly H5N1 bird flu strain has reached Victoria after a greater crested tern tested positive near Portland on July 30. The virus was first detected in Western Australia in June and has since spread across the southern coast through migratory birds. South Australia confirmed local transmission between birds on July 29, marking a critical escalation. Over 25 cases are now confirmed across Australia, prompting emergency animal disease response plans and mandatory poultry housing orders.

How the virus spread from Western Australia to Victoria

The H5N1 strain was first detected in a brown skua at Cape Le Grand National Park near Esperance, Western Australia, in June. The virus then spread rapidly across the southern coast via migratory birds. A second case in Western Australia was confirmed in a giant petrel. By late July, cases had reached South Australia, New South Wales, and Queensland before arriving in Victoria. A greater crested tern found near Portland tested positive on July 30, confirming Victoria’s first case.

Local transmission now occurring between wild birds

South Australian authorities confirmed on July 29 that H5N1 is transmitting between birds in the wild for the first time. Eleven suspected cases were detected among greater crested terns in South Australia, with seven in the state’s south-east and four on Kangaroo Island. Minister for Agriculture Julie Collins confirmed the local transmission on July 29, warning that further detections are expected. One suspected case near Seal Bay on Kangaroo Island has raised concerns for an endangered sea lion colony at the popular tourist site.

Threat to poultry farms and food supply

The detection has alarmed Victorian farmers after the 2024 H7N8 outbreak resulted in almost 2 million birds being culled and disrupted egg supplies to supermarkets. Victorian Chief Veterinary Officer Graeme Cooke has extended mandatory voluntary housing of poultry to a minimum of 14 days from July 30. The 2024 outbreak killed 1.3 million birds, followed by 600,000 in 2025. Victorian Farmers Federation President Ryan Milgate noted the current detection is in a wild bird, meaning commercial flocks remain unaffected at this stage, but preparation has been extensive.

Government response and public reporting

Victoria has enacted its State Emergency Animal Disease Response Plan following the positive test. Genetic testing is underway at the CSIRO’s Australian Centre for Disease Preparedness at Geelong to formally confirm the result. Chief Veterinary Officer Cooke urged the public to report any cluster of five or more sick birds of any species, or even a single sick or dead seabird, waterbird, shorebird, bird of prey, or marine mammal. A concerned member of the public discovered the infected tern and reported it to Wildlife Victoria on July 29.

Final Thoughts

With H5N1 now confirmed in Victoria and local transmission occurring in South Australia, Australian authorities face a critical wildlife emergency. The virus has spread to five states in just six weeks, and mandatory poultry housing orders are in effect. Farmers and wildlife officials must remain vigilant as the strain continues to move through migratory bird populations.

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