In May and June of 2024, ten Australian poultry farms in Victoria, New South Wales and the Australian Capital Territory were infected with highly pathogenic avian influenza of the H7 strain (H7 bird flu).
Avian influenza is a viral disease of birds found globally, and many low pathogenicity strains that cause no or mild disease circulate in Australian wild birds. Highly pathogenic strains in poultry farms can cause outbreaks of severe disease, resulting in many sick and dead birds. State and federal authorities need reliable testing and accurate information about outbreaks like this, so they can quickly respond to minimise the spread and damage of the virus.
As Australia’s national reference laboratory, CSIRO’s Australian Centre for Disease Preparedness (ACDP) is responsible for confirming (or excluding) disease diagnosis in samples sent by state or territory laboratories.
For this event, ACDP conducted more than 2700 tests on samples sent from affected properties.
Using advanced genetic testing to understand the outbreaks
In the 2024 outbreaks, H7 bird flu was first confirmed by ACDP at properties in Victoria, then New South Wales and the Australian Capital Territory. Authorities, industry and the public needed crucial information: had one strain of bird flu spread across all three states, or was there more than one outbreak?
Using advanced genetic testing, scientists at ACDP could show there were actually three virus strains causing three separate outbreaks:
- the H7N3 strain at seven properties in the Meredith area of Victoria
- the H7N9 strain at one property in the Terang region of Victoria
- the H7N8 strain at two properties in the Hawkesbury district in NSW, and at one property in the ACT.
Having three separate outbreaks at once was an unprecedented event in Australia.
Scientists at ACDP ran several advanced tests to analyse the genome sequence of each virus sample they received. By comparing each sample’s genetic code, ACDP could see the strains were different. They were more closely related to low pathogenic strains known to be carried by Australian wild birds, and scientists could see each outbreak was likely to have spilled over from wild birds separately.
In addition, this information clearly showed that these strains were not the HPAI H5N1 strain causing widespread outbreaks in other parts of the world.
This genetic detective work helped authorities, and the public, better understand the viruses they were dealing with.
ACDP’s work continues
ACDP’s advanced genetic analysis was conducted more quickly than ever before, in hours instead of the days or weeks it used to take. This was possible because its scientists continually work to update and improve their methods, to make sure state and federal authorities have the best information available to help respond to disease outbreaks.
While ACDP’s role in the 2024 outbreaks may be over, its team continues to analyse hundreds of avian influenza virus samples collected by the National Avian Influenza in Wild Birds surveillance program. This work provides important early warning of new viruses that may be carried into Australia.
ACDP also helps keep track of the constant evolution of avian influenza strains circulating around the world, and is designated as a World Organisation for Animal Health, and Food and Agriculture Organisation, Reference Laboratory for Avian Influenza. In this capacity, ACDP is continuing to support government and the nation to be prepared for possible outbreaks of bird flu, including the H5 strain overseas.
Read our article about bird flu dynamics in Australia's wild birds for more information.
In May and June of 2024, ten Australian poultry farms in Victoria, New South Wales and the Australian Capital Territory were infected with highly pathogenic avian influenza of the H7 strain (H7 bird flu).
Avian influenza is a viral disease of birds found globally, and many low pathogenicity strains that cause no or mild disease circulate in Australian wild birds. Highly pathogenic strains in poultry farms can cause outbreaks of severe disease, resulting in many sick and dead birds. State and federal authorities need reliable testing and accurate information about outbreaks like this, so they can quickly respond to minimise the spread and damage of the virus.
As Australia’s national reference laboratory, CSIRO’s Australian Centre for Disease Preparedness (ACDP) is responsible for confirming (or excluding) disease diagnosis in samples sent by state or territory laboratories.
For this event, ACDP conducted more than 2700 tests on samples sent from affected properties.
Using advanced genetic testing to understand the outbreaks
In the 2024 outbreaks, H7 bird flu was first confirmed by ACDP at properties in Victoria, then New South Wales and the Australian Capital Territory. Authorities, industry and the public needed crucial information: had one strain of bird flu spread across all three states, or was there more than one outbreak?
Using advanced genetic testing, scientists at ACDP could show there were actually three virus strains causing three separate outbreaks:
- the H7N3 strain at seven properties in the Meredith area of Victoria
- the H7N9 strain at one property in the Terang region of Victoria
- the H7N8 strain at two properties in the Hawkesbury district in NSW, and at one property in the ACT.
Having three separate outbreaks at once was an unprecedented event in Australia.
Scientists at ACDP ran several advanced tests to analyse the genome sequence of each virus sample they received. By comparing each sample’s genetic code, ACDP could see the strains were different. They were more closely related to low pathogenic strains known to be carried by Australian wild birds, and scientists could see each outbreak was likely to have spilled over from wild birds separately.
In addition, this information clearly showed that these strains were not the HPAI H5N1 strain causing widespread outbreaks in other parts of the world.
This genetic detective work helped authorities, and the public, better understand the viruses they were dealing with.
ACDP’s work continues
ACDP’s advanced genetic analysis was conducted more quickly than ever before, in hours instead of the days or weeks it used to take. This was possible because its scientists continually work to update and improve their methods, to make sure state and federal authorities have the best information available to help respond to disease outbreaks.
While ACDP’s role in the 2024 outbreaks may be over, its team continues to analyse hundreds of avian influenza virus samples collected by the National Avian Influenza in Wild Birds surveillance program. This work provides important early warning of new viruses that may be carried into Australia.
ACDP also helps keep track of the constant evolution of avian influenza strains circulating around the world, and is designated as a World Organisation for Animal Health, and Food and Agriculture Organisation, Reference Laboratory for Avian Influenza. In this capacity, ACDP is continuing to support government and the nation to be prepared for possible outbreaks of bird flu, including the H5 strain overseas.
Read our article about bird flu dynamics in Australia's wild birds for more information.