Avian influenza
Avian influenza (AI), also known as ‘bird flu’, is a virus that causes high numbers of deaths in poultry, wild birds, and some mammals. Occasional infections have been detected in humans.
The virus is classed into 2 types, depending on its severity in poultry:
- low pathogenicity avian influenza (LPAI) – less disease and can readily mutate into HPAI
- high pathogenicity avian influenza (HPAI) – more disease with mortality rates up to 100% possible.
Most birds can become infected and spread the virus to a wide range of species.
Global situation
Since 2021, there have been many detections overseas of HPAI viruses in wild birds, wild mammals, and poultry. HPAI H5N1 clade 2.3.4.4b has been the predominant strain during the past 24 months.
Both individual and mass mortalities have been observed. Based on the latest reporting to the World Organisation for Animal Health (WOAH), the new and ongoing HPAI outbreaks have significantly increased. These are notably causing losses in the sub-Antarctic islands and countries across most continents.
Avian influenza in Australia
Detections of HPAI are rare in Australia, which is currently the only continent free from the virus. There is an increased risk of HPAI being introduced to Australia through:
- its rapid global spread
- migratory birds returning to our shores annually.
All previous HPAI outbreaks have been in poultry – these occurred in other states and were successfully contained and eradicated. HPAI has not been found in poultry in South Australia.
LPAI circulates among wild native birds and is more common in waterfowl (e.g. ducks and geese) and shorebirds (e.g. waders and sandpipers), both of which are the natural reservoirs of the virus.
Outbreak preparation
Outbreak preparation
The Biosecurity division of PIRSA works with the National Avian Influenza Wild Bird Surveillance Program, which is coordinated by Wildlife Health Australia.
This program monitors AI virus presence in wild birds to understand the risks and prevent infection in poultry flocks. Disease investigations are also performed in poultry and wild bird mortalities, testing for avian influenza.
If HPAI is detected in Australia, it is declared as an emergency animal disease. Immediate actions will focus on its eradication and minimising the impact of any outbreak.
Learn about the detailed response undertaken by Animal Health Australia.
Symptoms in birds
Avian influenza can be confused with many other diseases that have similar clinical signs. The infection can vary in severity, including the following:
- sudden death in several birds in a short space of time – typical of HPAI infection
- respiratory distress (open mouth breathing, coughing, sneezing)
- nervous signs (twisted neck, inability to stay upright, inability to fly, uncoordinated movement, walking or swimming in circles, partial or full paralysis)
- swollen head
- reluctance to move, eat, or drink
- reduced egg production
- misshapen eggs
- diarrhoea
- droopy appearance.
AI can be highly infectious, resulting in rapid spread in highly pathogenic forms of the disease.
When to report
Early detection of HPAI is essential for controlling the disease.
The following observations must be reported immediately to the EAD hotline. If unsure, call the hotline for advice about bird mortalities.
| Commercial poultry | Backyard poultry (50 birds or less) | Wild birds and animals |
|---|---|---|
| 2% or more deaths within a week | Both:
| Either:
|
Reducing risks
There is no vaccination for AI virus for poultry in Australia. Biosecurity is the best defence to protect poultry flocks from disease, with a focus on minimising contact with wild birds.
Husbandry and hygiene practices for poultry
Husbandry and hygiene practices for poultry
To achieve a high level of biosecurity, make sure:
- feed and water are kept inside sheds where practical, or covered so they are difficult for wild birds to access
- fresh feed and water is provided daily
- feed and water spaces are clear of faeces and other organic matter
- drinking water is treated, especially if it is straight from a natural water source, such as a river or dam
- treated drinking water is regularly tested for effectiveness
- the presence of vegetation that attracts wild birds, particularly waterfowl, is minimised
- poultry species are prevented from mixing – keep chickens, ducks and turkeys separate
- visitor contact with birds is limited
- new birds are kept separate from your flocks in a quarantine pen for at least 4 weeks, until you are sure they are disease-free after transportation
- your overall flock’s health is maintained.
Human health
Human health
The spread of avian influenza from birds to people is rare but may occur with some strains of the virus if there is close contact with:
- infected birds or their droppings
- heavily contaminated environments.
Always practise good personal hygiene when handling birds, including washing your hands thoroughly with soap and water.
If you are experiencing cold or flu symptoms after handling sick birds or poultry, call your doctor for medical advice. Find more information about AI in humans via the Australian Government Department of Health and Aged Care.
