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 (this is called a spillover event)
high pathogenicity avian influenza (HPAI) – more disease with mortality rates up to 100% possible.

LPAI circulates among wild native birds and is more common in waterfowl (ducks and geese) and shorebirds (waders and sandpipers), both of which are the natural reservoirs of the virus.

LPAI to HPAI spillover events have from time to time caused outbreaks of avian influenza in Australia. These have not been the H5 strain currently impacting birds and wildlife globally; Australia remains free from H5N1 HPAI (H5 bird flu).

Most birds can become infected and spread the virus to a wide range of species. There is an increased risk of HPAI being introduced to Australia through:

its rapid global spread
migratory birds and other wildlife returning to our shores annually.

Avian influenza in Australia

Detections of HPAI are rare in Australia. All previous outbreaks have been in poultry. HPAI has not been found in poultry in South Australia. Between May and June 2024, outbreaks of the H7 strain of HPAI were declared in Victoria, New South Wales and the Australian Capital Territory. All outbreaks were successfully eradicated.

In February 2025, Agriculture Victoria confirmed the presence of an H7 strain of HPAI at poultry properties in northern Victoria. Read more about the current response to avian influenza by Agriculture Victoria.

There are currently no restrictions on the movement of poultry and fertile eggs into SA beyond the normal requirements for poultry movement.

Find updates on the current disease situation in Australia, including state and territory-specific information about how to protect your birds.

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 avian influenza 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.

H5N1 - what to be aware of

H5 bird flu, specifically high pathogenicity avian influenza H5N1 clade 2.3.4.4b, is a serious and highly contagious strain that has moved quickly around the world. Australia is currently the only continent free from this strain of H5 bird flu.

Wild, farmed and pet birds can catch bird flu. Overseas, other animals have become infected by this strain of H5 bird flu. These were mainly marine mammals and bird-eating scavengers but cases have been detected in wildlife and livestock.

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.

If H5 bird flu reaches Australia, this disease will have significant impacts on our agricultural industries, unique wildlife and the national economy.

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.

Avian influenza can be highly infectious, causing rapid spread in highly pathogenic forms of the disease.

When to report

Early detection of avian influenza is essential for controlling the disease. The following observations must be reported immediately – if unsure, call the Hotline for advice about bird mortalities.

Commercial poultry	Backyard poultry (50 birds or less)	Wild birds and animals
Either: 2% or more deaths above baseline mortalities within a week drop in egg production, with or without respiratory signs	Both: more than 10% deaths within 3 days birds exhibiting respiratory or nervous signs	Any: 1 or more sick or dead waterfowl (ducks, geese, swans), shorebirds (stilts, avocets), seabirds or predatory and scavenging species in the same place 5 or more dead wild birds of any other species in the same place unusual signs of disease

If you see multiple sick or dead birds:

Avoid contact with them and keep pets away – don’t touch them.
Record the date, time, location, species (type of bird), and how many.
Report your observations to the Emergency Animal Disease Hotline.

When to report - resources

Reducing risks

Australia has well-established national response arrangements in place to respond to emergency animal diseases, including avian influenza.

Avian influenza spreads from wild birds to poultry. Even with movement conditions in place to control interstate HPAI detections when needed, SA poultry is at ongoing risk from wild birds in our state.

Good biosecurity is critical at all times to protect poultry flocks from disease.

All poultry owners must have biosecurity plans. Best practice farm hygiene and biosecurity practices are adopted in the Australian poultry industry and are standard practice. National farm biosecurity manuals outline these measures, and you can download this fact sheet for tips to keep your flock safe. ( PDF 92.9 KB )

There is no avian influenza vaccination in Australia for poultry.

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 avian influenza 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 avian influenza 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 how government and industry work together to respond to disease outbreaks.

Husbandry and hygiene practices for poultry

To achieve a high level of biosecurity, restrict contact between poultry and wild birds. Take these steps to maintain your overall flock’s health:

Keep feed and water inside sheds where practical, or covered so they are difficult for wild birds to access.
Make sure fresh feed and water is provided daily.
Keep feed and water spaces clear of faeces and other organic matter.
Ensure drinking water is treated, especially if it is straight from a natural water source, such as a river or dam. Treated drinking water should be regularly tested for effectiveness.
Change nesting materials on a regular basis.
Minimise the presence of vegetation that attracts wild birds, particularly waterfowl.
Make sure poultry species are prevented from mixing – keep chickens, ducks and turkeys separate.
Limit any visitor contact with birds. Check whether essential visitors have recently been at other premises where poultry are kept.
If you attend poultry shows, don’t allow your birds to mix directly with others.
Keep new birds separate from your flocks in a quarantine pen for at least 4 weeks, until you are sure they are disease-free after transportation.

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, including washing your hands thoroughly with soap and water, before and after handling birds and eggs.

People who have regular contact with poultry or other animals at risk of avian influenza are strongly recommended to have the seasonal flu vaccine each year.

If you are experiencing cold or flu symptoms after handling sick birds or poultry, call your doctor for medical advice.

SA Health has more information about avian influenza in humans – including symptoms, treatment and prevention.

Resources for vets

In October 2024 PIRSA presented an avian influenza professional development webinar for veterinarians. Recordings of the different sessions can be viewed on YouTube as listed below. While best viewed in the order presented, it is not essential. Corresponding fact sheets have also been provided.