H5 bird flu

Bird flu is a type of virus that mainly affects birds. It can also affect other animals and, on rare occasions, humans

Find out more at: Bird flu (Australian Centre for Disease Control Avian)

influenza virus strains are described as either:

• low pathogenicity avian influenza (LPAI), or
• high pathogenicity avian influenza (HPAI)

Most LPAI strains of the bird flu virus cause minimal disease in wild birds and poultry. HPAI strains have high mortality rates. Some LPAI strains can evolve into HPAI strains when they spread among poultry.

Different HPAI strains have different risks. For example, H7 strains such as H7N9, have previously caused serious outbreaks in poultry and Australia has successfully contained and eradicated H7 bird flu strains in the past.

Overseas, the highly contagious H5 strain (H5N1 clade 2.3.4.4b) has caused severe disease and high death rates in poultry, wild birds and affected mammals.

In recent years H5 bird flu has spread fast around the world. The wild birds that are most affected include waterfowl, shorebirds, seabirds and birds of prey or scavengers. Marine mammals have also been affected, with some detections in other animals like cats, goats, alpacas and pigs.

Overseas, H5 bird flu has been detected in:

• domestic pets including cats and dogs
• farm animals including dairy cows, and sporadically pigs, sheep and goats
• marine mammals including dolphins and seals
• wild animals including foxes and polar bears

Infected animals might look very sick—or show no signs at all. Sometimes birds can die suddenly without warning.

That’s why it’s important to report any sick or dead birds or other animals, even if you're unsure.

Keep watch for signs of bird flu. 

 Common signs of bird flu in animals Wild birds:

• can’t stand, walk, or fly properly
• droopy or puffed-up appearance
• breathing problems (panting or sneezing)
• unusual head or neck posture
• sudden death (especially in large numbers) Poultry (chickens, ducks, etc.)
• sudden drop in egg production
• ethargy or not eating/drinking
• swollen head or limbs
• bruising on comb, feet, or skin
• breathing issues or runny nose
• sudden death Mammals (seals, cows, cats, etc.)
• weakness or tiredness
• trouble walking or breathing
• seizures, tremors or walking in circles
• drooling or runny nose
• sudden illness or death

• Infected birds can spread the virus through body fluids, droppings and feathers. In the right conditions, the virus can survive in the environment for months.
• The virus can spread through contaminated clothing and shoes. It can also spread through animals, vehicles and equipment, and items like egg cartons.
• Most bird flu strains do not spread easily from animals to people. There is no evidence that the current H5 bird flu strain spreads between people. Bird flu transmission requires close contact with infected birds or other infected animals, or contaminated environments.

In June 2026, Australia had its first detections of the H5 bird flu in migratory seabirds on Australia’s southern coast.

You can read more on this detection at birdflu.gov.au.

The 2025 H7 bird flu outbreak in Victoria was eradicated in June 2025. This is a different strain to the H5 bird flu strain.

Australia has contained and eradicated H7 bird flu several times over the past 50 years. This demonstrates the strength of our established national response arrangements.