HPAI incursion risk assessment for Australia
The risk (likelihood and consequence) of HPAI H5N1 clade 2.3.4.4b incursions into Australia via wild birds
High pathogenicity avian influenza (HPAI), or “bird flu”, is an infectious disease that causes severe illness and death in poultry and wild birds. HPAI can also cause disease in mammals, including rare cases in people. Since 2021, a new strain of HPAI, called HPAI H5N1 clade 2.3.4.4b, has caused significant illness and deaths in poultry and wild birds on all continents except Oceania. This strain of HPAI has not been detected in Australia.
To better understand the risk of HPAI and help guide preparedness efforts, the Australian Government Department of Agriculture, Fisheries and Forestry (DAFF) commissioned work to assess Australia’s vulnerability to this disease, including a risk assessment. The risk assessment report focuses on the likelihood and consequence of HPAI H5N1 clade 2.3.4.4b incursions into Australia via wild birds with establishment in wild birds, poultry or wild mammals.
The risk was assessed to have increased compared to previous risk assessments. This is partly because an outbreak of clade 2.3.4.4b is likely to have more severe impacts than previous strains of HPAI, including impacts on wild birds.
This risk assessment was based on information available as of the 20 July 2023. The global avian influenza situation is dynamic and since this report was commissioned HPAI emerged in the sub-Antarctic, thousands more wild birds and marine mammals have been infected, and a considerable number of scientific studies have been published addressing the ecology, evolution, virology, pathogenicity of this virus. As remaining knowledge gaps and uncertainties are being steadily addressed, sections of the risk assessment will be revised in due course. Key updates are noted in the document.
There is no way to prevent HPAI entering Australia through migratory movements of wild birds into Australia. It is important that individuals or groups who may observe or handle wild birds are aware of HPAI, to ensure appropriate reporting and investigation is undertaken and to ensure risks to themselves and other animals are minimised. The National Avian Influenza in Wild Birds Program will continue nationwide surveillance for all avian influenza viruses. Stay up to date via the DAFF and Wildlife Health Australia websites.
WHA would like to acknowledge the significant expertise and comprehensive assessments undertaken by Dr Marcel Klaassen (Deakin University) and Dr Michelle Wille (The University of Melbourne) in addition to critical contributions and feedback from members of the National Avian Influenza Wild Bird Steering Group.