Avian influenza (bird flu)

Alert

H5 bird flu has been confirmed in wild birds in Queensland, Western Australia, South Australia and New South Wales.

Queensland has activated emergency arrangements and is undertaking surveillance to determine the extent of the infection in wildlife.

On 31 July 2026, the Queensland Chief Veterinary Officer recommended extension of the voluntary (non-mandatory) housing of Queensland free-range commercial poultry, where practical and consistent with animal welfare requirements.

  • This extension is for a further 28-day period, until 28 August 2026.
  • It is a heightened biosecurity measure and will continue to be assessed as the national H5 bird flu response evolves.

Do not touch sick or dead wild birds or wildlife. If you suspect bird flu in any species of animal, you must report it immediately to the Emergency Animal Disease Hotline on 1800 675 888.

Avian influenza (AI) is a highly contagious viral infection of birds, including poultry. There are many strains of the virus, some of which cause no clinical signs (low pathogenicity), while others can be devastating to susceptible birds (high pathogenicity). Turkeys and chickens are particularly susceptible to the AI virus.

Under Queensland legislation, avian influenza viruses (low pathogenicity and high pathogenicity) are restricted and prohibited matter under the Biosecurity Act 2014, and must be reported.

Cause

AI is caused by a type A influenza virus in the Orthomyxovirus family.

Other names

  • Bird flu
  • Fowl plague

Distribution

Outbreaks of HPAI in Australia have occurred in domestic poultry since 1976 in Victoria, New South Wales, Queensland and the Australian Capital Territory.

Since 2021, a strain of HPAI virus (H5N1 clade 2.3.4.4b) has caused ongoing outbreaks throughout much of North America, South America, Europe, Asia and Africa, and into Antarctica and its islands.

In addition to outbreaks in poultry and a variety of wild bird species, disease and mass mortalities have been observed in a wide range of wild and domestic mammals (terrestrial and aquatic)—particularly in marine mammals and mammals that prey on or scavenge birds. The HPAI H5N1 virus has also been detected in dairy cattle, cats, goats and alpacas in the United States.

Hosts

Wild water birds are the natural hosts of low pathogenicity avian influenza (LPAI) viruses and frequently the source of AI infection in domestic poultry.

Wild birds (especially wild waterfowl) may contaminate domestic poultry feed or water supplies which, when ingested, may lead to infection or disease.

Animals affected

  • Wild birds
  • Poultry, including chickens, turkeys
  • Guinea fowl, quail, pheasants, emu, ostrich
  • Marine mammals
  • People—avian influenza could potentially be a serious human disease. Human illness and deaths have been confirmed in other countries in people who had close contact with avian influenza viruses (H5N1, H5N6, H7N7, H7N9, H9N2) through contact with infected poultry or their contaminated environment.

Clinical signs

AI can be confused with other diseases that have similar clinical signs. Early detection and reporting any unusual signs is essential for rapid control of the disease.

Clinical signs are variable and can be affected by the co-infection of other pathogens, the age of the birds, the environment and the severity of the virus itself.

In very severe forms the disease appears suddenly and birds can die very quickly (within 24 hours), sometimes without showing the classical signs of the disease.

Signs include:

  • sudden death
  • lack of coordination, tremors, swimming in circles
  • twisted necks or other unusual posture
  • inability to stand or fly
  • diarrhoea
  • difficulty breathing, coughing or sneezing
  • swelling around the head, neck and eyes
  • cloudiness or change in colour of the eyes
  • decrease in egg production
  • production of soft-shelled eggs.

In less severe forms, signs may also include:

  • respiratory signs (nasal discharge, coughing and sneezing)
  • swelling of the face
  • nervous signs
  • diarrhoea
  • reduced egg production.

Infected marine mammals may show signs including:

  • lack of coordination and tremors
  • seizures
  • difficulty breathing
  • nasal discharge
  • drooling
  • death, including the potential for mass mortality events.

Veterinarians can submit samples to the Biosecurity Sciences Laboratory from birds showing clinical signs of avian influenza virus infection.

Impacts

An outbreak of high pathogenicity (HPAI of any subtype) or low pathogenicity (LPAI of H5/H7 subtypes) avian influenza in Australian poultry could have serious social and economic impacts. Trade and markets will likely be disrupted and infected properties will have requirements (including movement control) imposed to control the disease under legislation.

It is critically important that any suspicion of this disease is immediately reported. If HPAI or LPAI (H5/H7) is detected, it is important to eradicate it as quickly as possible to control further spread and reinstate Australia's disease-free status for trade purposes.

How it is spread

Low pathogenicity strains of the AI virus are found in some wild bird populations in Australia, in particular waterfowl such as ducks and geese.

Spread from wild birds or waterfowl to domestic flocks occurs by either:

  • direct contact with infected wild birds, or
  • indirect contact such as contaminated pasture, water or feed.

Infected backyard poultry could also be a source of AI virus for commercial poultry through proximity to the commercial poultry farms, contaminated equipment, clothing or footwear.

Once a flock has been infected, the virus has the potential to change from a low pathogenicity strain to a high pathogenicity strain and potentially cause a significant disease outbreak.

In overseas incidents, spread of AI virus between flocks has been mainly due to poor biosecurity involving:

  • movement of infected birds
  • movement of contaminated feedstuffs, equipment, vehicles, personnel clothing and footwear on commercial or non-commercial properties
  • live bird markets (movement of infected birds, contaminated crates and contaminated vehicles)
  • egg collection
  • depopulation activities that infect nearby properties with birds through wind-borne spread (dust, droplets)
  • use of the same transport vehicle for dead bird pickup or waste collection from different premises.

Risk period

Incubation period of 3 to 5 days.

The virus is able to survive in the environment for variable amounts of time. It will usually survive the longest in water and the faeces of infected birds.

Monitoring and action

Poultry farmers, bird owners, bird fanciers and wild bird carers and watchers should be aware of this disease and remain vigilant for any unusual disease occurrence.

Do not handle sick or dead birds without suitable protective clothing and equipment (face mask, gloves).

Poultry

Comprehensive plans to respond to and control an outbreak of high pathogenicity avian influenza in poultry exist at a national level and have been developed in consultation with peak poultry industry body groups.

The nationally agreed response strategy is outlined under the AUSVETPLAN for avian influenza.

It includes:

  • immediate stamping out and disposal of infected and in-contact birds to remove the major source of virus
  • strict quarantine and movement controls to prevent the spread of infection
  • decontamination to remove and reduce the virus load
  • tracing and surveillance to locate the source of infection, locate other infected premises and determine the extent of the infection
  • zoning or compartmentalisation to define infected and disease-free areas.

Wildlife

The National Management Agreement for H5 HPAI in Wildlife (H5 NMA) is a national arrangement for responding to incursions of H5 high pathogenicity avian influenza in wildlife, where eradication or containment of the disease is unlikely.

The H5 NMA supports rapid and coordinated action through a ‘One Health’ approach that seeks to mitigate risks to human health, animal health, and the environment from outbreaks of H5 HPAI in wildlife.

Report

Call the Emergency Animal Disease Watch Hotline on 1800 675 888.

Your report will be reviewed, and we will contact you if more information is needed. Not all reports will require follow-up, sampling, or further action.

Veterinarians can:

Control

Prevention

Prevent AI through biosecurity measures that can help to prevent the introduction of the disease into the flock. It is the responsibility of all bird owners (commercial and non-commercial) to implement biosecurity measures to protect their animals from pests and disease.

In free-range situations, the risk is increased as birds are outside and have a higher chance of coming into contact with wild birds or their droppings, compared to flocks that are kept indoors. A high level of vigilance is needed in monitoring the health of your flock.

Vaccination

Control of AI without the use of vaccination is preferred. Vaccination has not been necessary in Australian outbreaks to date, but its usefulness has been demonstrated in overseas outbreaks.

If the disease is spreading at a significant rate, vaccination, enhanced biosecurity and other infection control measures may be implemented to protect flocks from infection.

National protection

The Australian and Queensland Governments understand the importance of protecting our poultry industry.

Measures taken to heighten biosecurity in Australia and Queensland for avian influenza include:

  • banning the importation of live poultry, aviary birds and eggs into Australia from countries that have avian influenza
  • inspection, quarantine and testing of poultry products (meat and/or egg products and products including feathers) and live birds at airports, seaports and international mail handling facilities
  • investigation of reported suspect infection in birds or poultry by Biosecurity Queensland veterinary officers and biosecurity officers
  • screening of relevant bird samples submitted for diagnostic purposes by the Biosecurity Sciences Laboratory.

Further information