🦢 H5N1 Avian Influenza Reaches Australian Mainland

A highly pathogenic strain of H5N1 avian influenza has been confirmed in multiple migratory seabirds across Western Australia and South Australia, marking the first detection of this globally circulating virus on the Australian mainland and completing its spread to all seven continents.

Timeline and Detection

Initial Detection in Western Australia

On June 14, 2024, a veterinarian discovered a sick brown skua on a remote beach at Cape Le Grand National Park, near Esperance, Western Australia. The bird was taken to a wildlife sanctuary but died overnight.

Testing by the CSIRO's Australian Centre for Disease Preparedness confirmed the bird was infected with H5N1 clade 2.3.4.4b—a highly pathogenic avian influenza strain. A second bird, a giant petrel found nearby, also tested positive for the same virus.

Subsequent Confirmed Cases

Since the initial detection, the following cases have been confirmed in Australia:

A total of five cases have been confirmed in Australia: four in Western Australia and one in South Australia. All detections have been in migratory seabirds visiting southern Australia. No cases have been found in Australian poultry or agricultural production systems.

Heard Island Outbreak

Prior to the mainland detections, the H5N1 strain was confirmed on Heard Island, an Australian external territory in the sub-Antarctic. A research voyage in January 2025 estimated that 13,359 southern elephant seal pups died from the virus—representing over three-quarters of the island's cohort of 17,364. Mortality rates reached up to 97% in some areas.

The virus was also detected in king penguins, gentoo penguins, Antarctic fur seals, and South Georgia diving petrels. Genetic analysis suggested the virus arrived on Heard Island around August 2025, likely via infected wildlife from the Crozet Islands, approximately 1,800 km away.

Australian Antarctic Program scientists reported that on-ground observations indicated no signs of ongoing mass mortality events in the areas they visited during sample collection. Aerial survey data from the voyage continues to be analyzed.

Government Response

Federal Government Actions

The Australian government has invested more than $113 million to strengthen bird flu preparedness and enhance national response capability. This includes delivery of rapid response equipment in every state and territory and building resilience in Australia's most at-risk native species.

An additional $11.2 million was announced in the 2024-25 budget for at-risk species resilience. A national taskforce, jointly led by the National Emergency Management Agency and federal agriculture, environment, and health departments, has been preparing since 2024. The government has developed over 100 response plans for important natural sites and susceptible species.

State Government Actions

Western Australia: The Department of Primary Industries and Regional Development (DPIRD) is leading the animal health response, with divisional commands established in South West and South Coast regions. The DPIRD patrol vessel PV Hamelin has been deployed for monitoring wildlife colonies in priority areas.

South Australia: The state has introduced mobile laboratories, rapid response vehicles, and decontamination units to contain potential outbreaks. $8.1 million has been invested from state and federal governments into PIRSA for emergency response, surveillance, diagnostics, and workforce readiness. An additional $3.5 million was allocated for the Department for Environment and Water to strengthen wildlife protection.

Industry Response

Inghams Group, Australia's largest poultry producer, implemented a complete lockdown across all its Western Australian operations as a precautionary measure, preventing all non-essential access to farms and processing operations. The company is seeking a regional housing order from the Australian Government's Chief Veterinary Officer to allow free-range poultry to be kept indoors.

Several poultry operations in southern WA have implemented enhanced biosecurity measures, including confining chickens indoors and closing farm shops. The Esperance Poultry Association cancelled its scheduled show as a precaution.

International Response

Papua New Guinea (PNG) suspended imports of Australian poultry and eggs following the detections, but later lifted the suspension. PNG is Australia's largest overseas customer for chicken meat, purchasing approximately half of Australia's total exports, which reached a record $133 million in 2023-24.

Risk Assessment

Human Health

The risk to human health from H5N1 is assessed as low by Australian health authorities.

Human infections remain rare globally and typically occur after close contact with infected poultry or contaminated environments. From 2003 to early 2026, 997 reported human cases were recorded globally, with 478 fatalities.

A small number of people who had direct contact with the affected birds have been identified, contacted, and will be monitored under national guidelines. The Australian Centre for Disease Control states that properly cooked poultry products and eggs remain safe to eat.

Health authorities recommend receiving the seasonal influenza vaccine to reduce the risk of co-infection with human and avian influenza viruses.

Wildlife Impact

A federal government analysis of Australia's 800 bird species and 350 mammal species has assessed more than 150 native bird species as being at "very high risk" of extinction or major decline if they contract the H5N1 strain. Over 10 mammal species are also at high risk, including the Australian sea lion, subantarctic fur seal, and Australian fur seal.

Species identified at very high risk include:

• Red goshawk
• Fairy tern
• Plains-wanderer
• Shy albatross
• Black swan
• Western hooded plover
• Short-tailed shearwater (migratory species)

Experts predict the virus could spread across almost all of Australia within six to 12 months and recur for three to five years before potentially stabilizing. Black swans are considered particularly susceptible due to their lack of necessary immune components to detect H5N1 and their out-of-control inflammatory response.

Poultry Industry

The H5N1 strain is highly lethal to chickens, turkeys, and quail. Ducks can be silent carriers. Australia has no history of H5N1 outbreaks and has been the only continent free of this strain.

Previous outbreaks of H7-type bird flu in Australia (2024-2025) required culling of over 2.4 million egg-laying chickens—representing 10% of the national flock—and led to egg price increases.

Public Advisory

Do not touch or handle sick or dead birds or marine mammals.

Authorities advise the public to:

• Keep distance, take a photograph, note the location
• Report sightings to the Emergency Animal Disease Hotline at 1800 675 888 or visit birdflu.gov.au
• Keep pets away from wildlife, including preventing cats from roaming and keeping dogs on leads in wildlife areas
• Bird owners should prevent wild birds from contacting domestic birds, keep enclosures clean, and wash hands thoroughly before and after handling birds

Signs of infection in animals include: sudden death, difficulty breathing, standing, walking, or flying, unusual behavior, swelling or discoloration, and respiratory distress.

Vaccination Status

Routine vaccination for poultry flocks against H5N1 is currently not permitted in Australia due to export status considerations.

The government has indicated that vaccination would primarily be considered for wildlife. Some countries have vaccinated threatened species such as California condors and king penguins. Australia has conducted limited trials on captive birds, and vaccination is considered part of the toolbox for specific species. This policy could change if a major outbreak occurs.

Surveillance

Since June 19, over 670 reports have been made to the Emergency Animal Disease Hotline in Western Australia, with 53 prioritized for investigation based on risk. Twenty-five negative test results have been returned across various coastal regions to date. In South Australia, over 780 bird samples have been tested since January 1.

The Eyre Bird Observatory, located near Esperance, has been closed since February due to a medical emergency involving a volunteer, limiting monitoring capabilities in a critical area. BirdLife Australia is working with the Department of Biodiversity, Conservation and Attractions and the local shire to reopen the facility, though no timeline has been confirmed.

Context

The H5N1 clade 2.3.4.4b strain originated in Asia and has spread globally since 2021. It has caused significant mortality in wild birds and mammals worldwide, including over 200 million chickens culled in the United States since the virus arrived there.

The virus has repeatedly spilled over into mammals, including dairy cattle, seals, and sea lions. In Argentina (2022), 96% of southern elephant seal pups died from the virus, and in South Georgia, breeding females decreased by 47% between 2022 and 2024.