What is 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. See more on H5 bird flu and human health (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. 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.

Signs of H5 bird flu

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.

Common signs of H5 bird flu in animals

Keep watch for signs of H5 bird flu.

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 (such as chickens, ducks)

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

Mammals (such as seals, cows, cats)

• weakness or tiredness
• trouble walking or breathing
• seizures, tremors or walking in circles
• drooling or runny nose
• sudden illness or death.

How H5 bird flu spreads

H5 bird flu can spread through:

• body fluids, droppings and feathers of infected birds (in the right conditions, the virus can survive for months)
• other infected animals
• contaminated clothing and shoes, vehicles and equipment
• 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.