Avian influenza (bird flu)

Avian influenza virus strains are designation as low pathogenic (LPAI) or highly pathogenic (HPAI), according to the severity of disease and their potential to cause mortality in infected poultry. Such categorisation does not relate to how infectious the viruses may be to humans, other animals, or other species of birds.

Most strains of AI virus cause minimal disease in wild birds and in poultry. However, some LPAI strains can evolve into HPAI strains when they spread among poultry, causing severe disease and mortality. Sometimes these HPAI viruses spill back to wild birds where they may also cause disease or death in certain species and pose a risk of spreading into naïve poultry populations.

Avian Influenza viruses (type A) are categorised into subtypes based on their two surface proteins Hemagglutinin (HA) (16 subtypes H1-H16) and Neuraminidase (NA) (9 subtypes N1-N9), with many combinations occurring. The H5 and H7 AI virus subtypes pose the greatest potential to evolve into HPAI viruses and as such are closely monitored by animal health and biosecurity agencies.

H5N1 is a particular strain of highly pathogenic avian influenza.

All bird species are thought to be susceptible, with reports showing it to occur in more than 140 species including domestic poultry - chickens, turkeys, pheasants, partridges, quail, pigeons, ducks, geese, guinea fowl and ostriches - and wild birds.

AI viruses usually only infect birds but pigs, tigers, leopards and domestic cats have also been infected with H5N1.

The clinical signs are variable and depend on a range of factors including the virulence of the virus, the species and age of the birds infected, the presence of concurrent diseases, and the environment.

In severe forms, such as H5N1 infection, the disease appears suddenly and birds die quickly.

Common signs to look for in poultry are:

• sudden death in several birds
• ruffled feathers
• unusual head or neck posture
• inability to walk or stand
• reluctance to move, eat or drink
• droopy appearance
• respiratory signs such as laboured breathing, nasal discharge or sneezing
• diarrhoea
• swollen head, wattle or comb, and or purple discoloration
• internal haemorrhage (evident on butchering)
• occasionally neurological manifestations, and
• a drop in egg production.

Diagnosis of AI can only be confirmed through laboratory testing.

No. AI is a severe viral disease and there is currently no effective treatment available for birds once clinical signs of disease appear. Vaccines are available for certain subtypes of avian influenza, which may protect poultry from clinical signs of disease if they subsequently become infected. However, routine vaccination for AI is not permitted in Australia.

AI virus is excreted in the saliva, nasal secretions and faeces of infected birds. It is spread between infected birds via close contact, the movement of infected live birds and virus-contaminated poultry products, feed, equipment and materials. The virus can survive long periods in faeces and water and on feathers, eggs or in meat.

In Australia, AI could spread to domestic birds through contamination of feed and water by wild bird droppings or secretions. Infected migratory shore and wading birds could transmit AI to Australian nomadic waterbirds, which could mingle with and spread the virus to domestic birds.

If you own birds, you can take practical measures to avoid their water and feed becoming contaminated, such as storing feed in sealed containers away from wild birds and avoiding opportunity for wild birds to access their feeders and water supply.

Other measures might include:

• using safe water sources such as town or bore water, if these sources are not available, drinking water may be treated with chlorine or via other methods to inactivate any potential viruses;
• using netting or fencing to keep wild birds from accessing poultry runs; and
• regularly clean bird equipment and pens with a household disinfectant, do not share bird equipment with other bird owners.

Always thoroughly wash your hands and clothing with soap and hot water before and after handling birds. Footwear can be cleaned with normal household disinfectants, washing soda or vinegar.

See our bird biosecurity information.

WHO, FAO and the OIE agree that control of avian influenza infection in wild bird populations is not feasible and should not be attempted.

Wild waterfowl have been known for some time to be the natural reservoir of all influenza A viruses. Migratory birds can carry these viruses, in their low-pathogenic form, over long distances, but do not usually develop signs of illness and only rarely die of the disease.​

Australia has a surveillance program to detect incursions of AI. The National Avian Influenza Wild Bird Surveillance (NAIWB) program collects and screens samples from Australian wild birds for AI viruses and the data generated are used to monitor and understand AI in wild birds in Australia. Over the life of the 18-year program, thousands of Australian wild bird samples have been screened with no high pathogenicity AI viruses detected in our wild birds.

The H5N1 strain has never been reported in Australia. There have been seven outbreaks of other highly pathogenic avian influenza strains (which have not caused disease in humans) in commercial bird flocks in Australia, all of which were successfully eradicated. The last reported case was in 2013 in Young, New South Wales. Previous outbreaks occurred in commercial poultry farms in New South Wales (2012), Victoria (1976, 1985 and 1992) and Queensland (1994).

The recent global circulation of HPAI viruses is posing unprecedented risks for vulnerable wildlife species.

HPAI viruses pose considerable risk for poultry industries.

The risk of a human influenza outbreak caused by avian influenza viruses is very low.

There is low likelihood of a human influenza outbreak developing in Australia as a result of migratory birds carrying HPAI virus to Australia. If a human pandemic influenza arose from avian influenza virus spill over and adaption (recombination or mutation) for increased transmissibility in humans, it would most likely occur elsewhere in the world, where poultry and human population densities are higher and where the viruses are considered endemic, and any spread to Australia would be from international travellers.

Waterfowl, which are a common host of AI viruses, are thought to have had a role in the spread of the H5N1 virus in Europe, Asia and Africa but they do not normally migrate to Australia. A number of wading bird species do migrate to Australia, but they are not common hosts or spreaders of HPAI viruses. Australia’s strict biosecurity measures prevent the disease from coming into Australia through imported birds or poultry products.

Talk to your local vet, the Chief Veterinary Officer (CVO) in your state or territory or call the 24 hour Emergency Animal Disease Watch Hotline:

Phone 1800 675 888 - freecall from within Australia

Transmission to humans occurs predominantly through handling live or dead infected birds or very close contact with them and their excretions. Clinical signs and symptoms of AI in humans include fever, sore throat, respiratory distress, pneumonia and in some cases death.

People do not get infected with AI through eating properly cooked chicken meat and eggs. There is currently no evidence of efficient human-to-human transmission with H5N1 avian influenza viruses.

If AI were to pose a significant threat (direct or indirect) to Australia's human population, the Australian Government would activate the Australian Health Management Plan for Pandemic Influenza. This plan provides direction for the development of actions by all Australian Governments, their agencies and emergency services in the event of such an occurrence.

What's the difference between avian influenza in birds, human influenza and pandemic influenza? And where does H5N1 fit in?Word [121 KB] - a short non-technical and 'plain English' paper on the disease and its risk to humans.

Yes, it is safe to eat properly cooked chicken meat and eggs.

Before departing discuss the risk of avian influenza with your doctor as part of your routine pre-travel health checks.

Australians travelling overseas are encouraged to avoid contact with live domestic birds (such as chickens, ducks and geese) on farms and in market places and avoid contact with sick or dead birds. Practise good hygiene at all times. Ensuring all uncooked poultry and eggs are handled hygienically with careful attention to hand washing after handling. Only eat properly cooked poultry and eggs. Proper cooking destroys the virus in poultry and eggs.

Based on available information, the evolution of a new clade of the H5N1 virus (described as H5N1 clade 2.3.2.1) identified in 2011 as circulating in poultry in parts of Asia poses no increased risk to public health. It is not considered unusual because influenza viruses are constantly evolving, especially in areas where they circulate regularly in poultry.

While travelling, it is suggested that you regularly check the Department of Foreign Affairs and Trade Travel Bulletin and country specific travel advice for information about any change to the current situation and whether additional precautions are recommended.

 

Returning to Australia

When returning to Australia from overseas, you must declare for inspection any poultry meat and products (including raw or cooked chicken and duck), fresh or preserved eggs or egg products, feathers and items containing feathers, poultry vaccines, and any other animal products, plant material and food.

Duck shooters have an important role in detecting and reporting diseases in wild birds!

Many species of wild birds, especially waterfowl, can carry the virus but generally show no signs of disease. Australia does not have migratory waterfowl with known flyways. The risk of waterfowl catching AI is posed when they mingle with shore birds and waders that come to Australia from Asia. In order to mount an effective Australian response, ongoing vigilance and early reporting of signs of the disease is crucial. The immediate reporting of anything unusual such as large numbers of dead birds will ensure authorities can contain and eradicate the disease as quickly as possible.

The H5N1 HPAI can infect humans who come in very close contact with infected birds or their excrement. The virus can survive in bird excrement for over a month and can survive in water for many days, if not weeks, depending on temperature. It is important to know that freezing poultry does not kill the virus.

Although H5N1 HPAI has never been detected in wild birds in Australia, several subtypes of low pathogenic avian influenza are known to circulate at low levels in waterfowl and shorebird species. These viruses are not believed to cause clinical signs of disease in wild birds. However, it is important for recreational shooters, bush walkers and others such as poultry owners to be vigilant and report any unusual signs of the disease in birds immediately.

It is recommended that if handling wild birds, you practise good hygiene. If you come across a large number of dead birds or any other circumstances that look unusual, you should not handle the birds without the proper personal protection equipment. You should then take immediate action. Telephone the national Emergency Animal Disease Watch Hotline on 1800 675 888. Alternatively, contact the Department of Primary Industries or Agriculture in your state or territory or tell your local veterinarian.

The Australian Government Department of Health website provides information of the human health aspects of bird flu. A hotline is also available for people requiring further information:

Phone 1800 004 599 - free call from within Australia (8:30am - 5pm)

Downloadable Fact Sheets

Avian Influenza (bird flu) PDF [74 KB, 2 pages] also available in other languages

Bird flu and our health PDF [62 KB, 1 page]

Protect your birds against bird flu and disease PDF [70 KB, 1 page] also available in other languages

Bird Biosecurity

National Biosecurity Manual - Poultry Production

Outbreak website (National pests and disease outbreaks)

Emergency Animal Disease Response Agreement

Australian Government Department of Health and Ageing

Farm Biosecurity Manuals

WHO Disease Outbreak Notice

United Nations Food & Agriculture Organization - Avian Influenza​