The Invasive Species Council says a suspected detection of avian influenza in a migratory wild bird in southern Western Australia is a deeply concerning development and a stark reminder that Australia must remain prepared for the arrival of highly pathogenic H5N1 bird flu.
Confirmatory testing is expected tomorrow after authorities detected avian influenza in a migratory wild bird on mainland Australia for the first time. If confirmed as highly pathogenic H5N1, it would mark a significant escalation in the threat facing Australia’s wildlife.
The virus has caused devastating impacts on wildlife populations globally and was recently linked to mass deaths of elephant seals on Heard Island.
Invasive Species Council Policy Director Dr Carol Booth said the detection highlighted both the importance of Australia’s preparedness efforts and the potentially severe consequences for native wildlife if H5N1 reaches the mainland.
‘At this stage we need to wait for testing to confirm whether this is highly pathogenic H5N1 bird flu, but the detection is deeply concerning given the devastating impacts the virus is having on wildlife around the world.
‘We desperately hope this is not the realisation of our worst dreams. The recently reported mass deaths of elephant seals on Heard Island were a harbinger of the potential catastrophe for Australian wildlife if the virus has made it to mainland Australia.
‘If H5N1 is confirmed, the government’s own risk assessment predicts potentially catastrophic impacts on native birds, while the virus’s increasing ability to infect mammals raises the prospect of severe impacts on marine mammals and other wildlife.
‘It is a good thing governments have spent the past two years preparing for the arrival of bird flu, but a mainland detection would be a critical test of Australia’s preparedness and response systems.
‘Even if this is a false alarm, it warns against any complacency. Australia needs to be ready at any time with clear response plans. It also highlights the urgency of mitigating other threats to potentially susceptible wildlife.’
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Images of seals and sea birds available here.
Background:
What to look out for
- The public should report any unusual bird deaths immediately by calling the Emergency Animal Disease Hotline on 1800 675 888.
- Wildlife Health Australia have produced detailed advice for people who encounter sick or dead wild birds.
- Look for:
- Small groups or clusters (5 or more) of sick or dead wild birds of any species.
- Individual or less than 5 sick or dead wild seabirds, waterbirds, shorebirds or birds of prey (e.g. eagles, hawks)
- Infected live birds may show a wide range of signs if they are sick, including:
- lack of coordination, tremors, swimming in circles
- twisted necks or other unusual posture
- inability to stand or fly
- diarrhoea
- difficulty breathing, coughing or sneezing
- swelling around the head, neck and eyes
- cloudiness or change in colour of the eyes.
- Australian H5N1 bird flu risk assessment:
- The Australian Government commissioned a risk assessment of High Pathogenicity Avian Influenza (HPAI) which was released in July 2023.
- The assessment found that the risk of ‘HPAI virus exposure and establishment in resident wild birds’ is ‘moderate/high’ and that the impact of this would be ‘catastrophic’, leading to an overall risk of ‘high’.
- Some key findings from this assessment include:
- Extrapolating from global outbreaks of HPAI H5N1 clade 2.3.4.4b, there are likely to be significant consequences associated with incursion and establishment of HPAI in Australia via wild birds given a moderate likelihood of incursions.
- The frequency of HPAI incursions into Australia via wild birds may be significantly lower compared with other continents and as a result, containment of outbreaks may be more achievable in the Australian context if they are identified early.
- Consequences to wild birds are assessed as CATASTROPHIC with moderate uncertainty, consequences to poultry are assessed as HIGH with moderate uncertainty and consequences to wild mammals are assessed as MINOR with moderate uncertainty.
- In multiple outbreaks the scale of mortality has been extremely high, often involving deaths of 100s, 1,000s or 10,000s of individuals with significant proportions of birds, resulting in mortality globally estimated to be in the millions.
- The Australian black swan has recently been determined to be highly susceptible.
Impacts overseas
- From Oct 2021-April 2023, more than 335 species of wild birds were impacted in 8,403 reported wild bird outbreaks globally.
- Since arriving in South America in late 2022, bird flu has killed more than 30,000 South American sea lions, 17,000 southern elephant seal pups and unknown numbers of porpoises, dolphins and otters, as well as at least 650,000 native birds.
- The mortality rate of elephant seal pups in Argentina’s Península Valdés reached 95% in 2023 compared to only 1% in 2022.
- Mass mortality events have been observed in penguins and skuas since bird flu arrived in Antarctica in early 2024. The virus arrived at the end of the breeding season for birds and mammals, so even greater impact is expected in the warmer months.
- In the UK, H5N1 has wiped out about 30% of the country’s breeding population of roseate terns, great skua and gannets.
- Since 2020, there have been outbreaks in Asia, Europe, the Middle East, Africa, North America, South America and Antarctica – Australia remains the only continent free of high pathogenicity avian influenza.
- Humans and other mammals can become infected through contact with live or dead infected animals, or contaminated environments. Current strains of avian influenza do not appear to transmit between humans.
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