Avian influenza (bird flu)

About bird flu

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 but this is rare – see Bird flu (avian influenza) on the SA Health website for information about bird flu in humans.

Birds can spread the virus to each other through their saliva, poo and mucus from their noses and mouths.

Healthy birds can catch it through contact with sick birds or contaminated water, food, soil or surfaces.

Sometimes other animals become infected by eating sick or dead birds, or by being in close contact with them.

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 can sometimes mutate into HPAI (this is called a spillover event).

H5 bird flu is a highly contagious type of HPAI – H5N1 clade 2.3.4.4b – which has spread quickly around the world.

Overseas, H5 bird flu has caused severe disease and high death rates in poultry, wild birds and some mammals.

H5 bird flu is different to the H7 strain of bird flu that was recorded in poultry in Australia in 2024 and 2025. All outbreaks of H7 bird flu were successfully eradicated.

In June 2026, H5 bird flu was detected in Western Australia, and shortly afterwards South Australia recorded its first confirmed case of H5 bird flu.

This is the first time this strain has been detected in Australia and has the potential to affect agricultural industries, wildlife and the national economy.

Signs of bird flu in poultry

Bird flu can be confused with many other diseases that have similar signs. The infection can also vary in severity with some animals appearing very sick and others showing no signs at all. Sometimes birds can die suddenly without warning.

Symptoms may include:

• sudden drop in egg production
• lethargy or not eating or drinking
• swollen head or limbs
• bruising on comb, feet, or skin
• breathing issues or runny nose
• sudden death.

Early detection is critical and South Australians are encouraged to remain vigilant.

If you see suspect bird flu, immediately contact the Emergency Animal Disease Hotline on 1800 675 888.

Reducing risks

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.

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.

Avian influenza is a nationally notifiable disease.

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 poo 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.