H5N1 - what to be aware of

Avian influenza is an infectious disease of poultry (and birds) and occurs worldwide. H5N1 however is different to other forms of avian influenza in that it circulates in wildlife in the HPAI form causing disease and deaths in wildlife- also expanded host range- particularly mammals.

Chickens, ducks, geese, turkeys, guinea fowl, quail, pheasants, emus and ostriches are included in the more than 400 species that are susceptible to avian influenza. Many species of wild birds, including waterfowl and seabirds can also carry the virus.

Mammals, especially carnivores and marine mammals, are known to be susceptible to H5N1 with infection presumed to occur via consuming infected birds. Infection of marine mammals is thought to occur via close contact with, or ingestion of infected birds, or contact with marine environments contaminated with virus from infected birds.

Livestock and domestic pets can also be susceptible.

Avian influenza strains vary in whether they cause disease and death in birds or not. The strains are classed as either low-pathogenicity (doesn’t cause significant disease in chickens) or high pathogenicity (causes severe disease in chickens). Low Pathogenicity Avian Influenza (LPAI) strains circulate at low levels in wild bird populations in Australia without causing significant disease and can occasionally transmit into poultry. Once circulating within poultry flocks, sometimes the virus can mutate into High Pathogenicity Avian Influenza (HPAI) and cause severe disease and death.

H5N1 is a strain of avian influenza that is on every continent except Australia. It differs from strains in Australia in that it circulates in wild birds as HPAI and has caused a large number of deaths in many different wild bird species, as well as wild mammals, including marine mammals such as sea lions.

HPAI H5N1 is a viral disease that spreads rapidly between birds. Virus is found in saliva and faeces as well as the tissues and fluids (blood) of infected animals and in eggs. HPAI can persist in the environment for extended periods under favourable environmental conditions.

HPAI virus can also be spread by the wind in poultry intensive areas; or virus contaminating footwear, clothing, or equipment that has had contact with birds or vehicle tyres. Biosecurity measures such as movement restrictions and disinfection practices are essential to minimise the spread of HPAI.

In severe cases of poultry (chickens, ducks and turkeys) involving sudden death, symptoms may not be seen. Mortalities occur as early as 24 hours after the first signs of the disease and frequently within 48 hours. Mortality rates of nearly 100% have been reported for severe and acute cases. In other cases, more diverse visible signs occur, and mortalities can be delayed for as long as a week.

The virus is mostly spread by wild birds, particularly ducks, after having direct contact with domestic poultry or birds, or by contaminating their food, water or bedding. It can also spread through movements of eggs, birds, people, vehicles and clothing, footwear, aerosols, water and feed.  For this reason, the disease remains a constant biosecurity threat.

Clinical signs of infection with HPAI in birds include:

• Sudden death without clinical signs
• Lethargy or reluctance to walk, eat or drink
• Droopy appearance or ruffled feathers
• Purple discolouration or bruising of the wattles, combs and legs
• Respiratory signs such as panting, nasal discharge, coughing or sneezing
• Swelling around the head and neck, incoordination, inability to walk or stand
• Watery or green diarrhea
• Sudden decrease in egg production

Infected wild mammals may show a wide range of clinical signs, including:

• neurological signs (paralysis, seizures and tremors)
• respiratory signs
• sudden death, including the potential for mass mortality events.

If you notice any unusual signs of disease, abnormal behaviour or unexplained deaths in your birds, contact your veterinarian, Local Land Services District Vet on 1300 295 799, or the Emergency Animal Disease Hotline on 1800 675 888.

Early detection is essential to reduce the potential impact of this disease.

Australia has successfully eradicated previous H7 strains of HPAI from the country, but the H5N1 HPAI strain that is currently circulating globally has shown its ability to establish and spread in a wide range of environmental and production systems around the world.
Vigilance and preparedness are essential safeguards.

Eggs and chicken meat are safe to eat provided they are handled and cooked as per standard food handling practices.

The World Health Organization considers the public health risk associated with H5 avian influenza viruses to be low.

Prevent pets from interacting with or eating sick and dead birds (including wildlife).

Regardless of whether you are a commercial producer, or you only keep a few chickens or birds in your backyard, putting biosecurity practices in place will help to protect your birds from disease.

• Restrict contact between your birds and wild birds wherever you can
• Provide feed and water in the poultry shed or use equipment that restricts wild bird access.
• Keep your poultry sheds, yards, aviaries and equipment clean
• Only buy healthy birds from reputable suppliers and always quarantine new birds before introducing them to the existing flock
• Limit any visitors to your birds, and check if essential visitors have recently visited other premises where poultry are kept
• Always practice good hygiene if you attend bird shows or poultry auctions
• Always wash your hands before and after handling birds and eggs
• Change into clean footwear before entering poultry houses or hen facilities, to stop the potential transfer of disease from outside
• Keep good records of bird movements or sales
• Record and report unusual signs of disease or increased deaths in your birds

If you notice any unusual signs of disease, abnormal behaviour or unexplained deaths in your birds, contact your veterinarian, Local Land Services District Vet on 1300 295 799, or the Emergency Animal Disease Hotline on 1800 675 888.

Outbreaks of H5N1 overseas have led to extensive losses of poultry, and mass mortalities of wild birds and mammals, particularly marine mammals (i.e. seals, sealions and dolphins) and mammals that prey or scavenge on birds.

Based on the level of impact in other countries, it is expected that an outbreak of H5N1 in Australia would have severe impacts on our wildlife and poultry industry.

In July 2023, the Australian Government commissioned an expert assessment of the current level of risk from H5N1 to wild birds in Australia. It summarised the risk of incursions and establishment of H5N1 in wild birds to be ‘High’. An abridged version of the risk assessment is available on Wildlife Health Australia’s (WHA) website.

Avian Influenza is a viral disease that spreads rapidly between birds. The virus is found in saliva and faeces as well as the tissues and fluids (blood) of infected animals and eggs.

Avian influenzas can persist in the environment (in soils and water) for extended periods under favourable conditions. They can be transmitted through respiratory aerosols and secretions (e.g. saliva, mucous) or faecal material of infected animals, or by ingesting infected animals. Contamination of clothing or equipment that has had contact with infected birds can also spread avian influenzas.

Wildlife Health Australia has cautioned that all bird species may be susceptible to infection from H5N1. However, not all species nor individuals will be affected in the same way.

Ongoing outbreaks and mortalities in wild birds, particularly waterfowl, shorebirds and seabirds, have been observed globally in a wide range of species, seen as individual bird deaths and mass mortalities. Birds that aggregate in high density are particularly at risk.

H5N1 has also resulted in the deaths of large numbers of terrestrial and aquatic mammals overseas, both wild and domestic. Animals that consume or come into contact with infected birds are susceptible. Pinniped species, namely seals and sea lions, are known to be at high risk.

Australia has unique endemic fauna not found elsewhere, so H5N1 impacts are more difficult to predict, but based on experience overseas, are expected to be significant for some of our native species, both avian and mammalian.

Some species may not show any signs of disease or show only very mild signs. In some cases, birds may die suddenly without displaying any clinical signs, or be found dead.

In birds, signs of disease usually appear in several or all birds in a flock, including:

• Sudden death without clinical signs
• Incoordination, head tremors, twisted necks, or head held upside down
• Tremors, spasms, seizures, circling
• Inability to stand or fly, decreased response to stimuli
• Rapid horizontal eye movements
• Unusual vocalisations
• Diarrhoea or regurgitation
• Emaciation
• Rapid or laboured breathing, coughing or sneezing
• Nasal or ocular discharge, salivation
• Swelling of the head
• Eye cloudiness or change in eye colour of birds.
• Lethargy or reluctance to walk, eat or drink
• Droopy appearance or ruffled feathers
• Poultry:
  • Purple discolouration or bruising of the wattles, combs and legs
  • Sudden decrease in egg production

Infected live marine mammals may show a wide range of clinical signs, including:

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

Avian influenza can only be confirmed through laboratory testing of samples collected by a veterinarian or government animal health officer.

There is no way to prevent H5N1 entering Australia because the most likely pathway for transmission is through the migratory movements of wild birds.

Biosecurity measures are the best means of disease control and should be relied upon instead of disturbing, displacing or harming wildlife.

Culling healthy wild birds is ineffective, impractical, and may be counterproductive to disease control. Most critically, it would likely jeopardise wild populations of threatened species.

All native birds and mammals in NSW are protected under biodiversity legislation.

Biosecurity and general hygiene

Although there are no confirmed detections of H5N1 in Australia, there are still several things you can do to reduce risks to domesticated birds, including:

• Maintain good baseline hygiene and biosecurity before, during and after working with poultry or around wildlife, and operate with an increased awareness of potential risks of wildlife disease.
• Restrict contact between your domestic birds and wild birds wherever you can, including contact with bird faeces.
• Provide feed and water inside the poultry shed, or use equipment that restricts wild bird access.
• Keep your poultry sheds, yards, aviaries and equipment clean.
• Only buy healthy birds from reputable suppliers and always quarantine new birds before introducing them to an existing flock.
• Limit any visitors to your birds, and check if essential visitors have recently visited other premises where poultry are kept
• Always practice good hygiene if you attend bird shows or poultry auctions
• Always wash your hands and arms before and after handling birds, eggs and bedding. Use abundant soap and warm water, dry hands thoroughly and reinforce with hand sanitiser (gel with 60 to 90% ethanol concentration).
• HPAI pathogen can be soil borne – pay particular attention to disinfecting equipment that has contacted the ground and change into clean footwear before entering poultry houses or hen facilities, to stop the potential transfer of disease from outside.
• Keep good records of bird movements or sales
• Record and report unusual signs of disease or increased deaths in your birds.
• Prevent pets from interacting with or eating sick and dead birds (including wildlife).
• If you need to dispose of dead birds, click here to access the guidelines for disposal.

How will I know there's an outbreak?

Across Australia, surveillance is underway as part of preparation for a possible outbreak of H5N1.

The National Avian Influenza Wild Bird (NAIWB) Surveillance Program coordinates both targeted and general surveillance of wild birds. Targeted surveillance focusses on sampling waterfowl (e.g. ducks, geese, swans) from locations where they are known to mix with seabirds or where they are in close proximity to poultry and humans. General surveillance focusses on testing from mass mortality events in wild birds around Australia and in the Australian Antarctic Territory.

In NSW, the DPIRD conducts surveillance under the NAIWB Surveillance Program. Current surveillance sites are at the Fivebough and Tuckerbill wetlands (Fivebough swamp), Leeton and Dangars Lagoon, Uralla and a long-term existing site in the Hunter Valley.

At each site, a minimum of 300 samples are collected each year over 6 samplings per year, with at least one per season (Spring, Summer, Autumn and Winter).

Since the program started in 2006, thousands of Australian wild bird samples have been screened. This helps monitor avian influenza viruses in wild birds and provides virus genetic information on newly detected strains. While LPAI viruses are regularly detected in wild birds, however no HPAI viruses have yet been detected in wild birds.

If H5N1 is detected in NSW, information will be published on:

• https://www.outbreak.gov.au/
• https://www.dpi.nsw.gov.au/dpi/bfs/animal-biosecurity/avian-influenza

The NSW BioResponse App, also provides up-to-date information about biosecurity emergencies.