Avian influenza (AI) - questions and answers
What are the clinical signs of avian influenza in birds?
The clinical signs are extremely variable depending on many factors such as the type of bird, the virus subtype and the presence of other diseases. Infected birds may die shortly after acquiring the infection with no obvious signs or they may show a variety of symptoms including breathing difficulties, coughing, swollen head, dark comb and wattles, depression, drop in egg production, changes in egg shell colour, loss of appetite, decreased feed intake and decreased vocalisation. Nervous signs like tremors of the head, unsteady gate, twisted necks and other unusual positions of the head and body sometimes occur. These clinical signs are not specific to avian influenza and can be seen in other poultry diseases.
How does avian influenza generally spread?
Avian influenza (AI) can be spread by movements of infected birds (domestic or wild), through droppings and secretions of infected birds directly or through movement of contaminated objects, clothing or vehicles. Windborne spread from infected large flocks is also possible over short distances. Other animals like cats and dogs can also spread the AI virus if they come in direct contact with contaminated materials or infected birds.
Are there any avian influenza viruses present in Australia?
Yes. Some subtypes of the avian influenza virus that are not known to cause disease have occasionally been found in wild birds and therefore it is very likely that these subtypes are continuously circulating among some populations of wild birds in Australia.
Has Australia ever had an outbreak of avian influenza?
Yes. There have been a number of outbreaks of avian influenza in domestic poultry since 1976 in Victoria, Queensland and NSW. All outbreaks were contained and successfully eradicated.
What is H5N1 ('bird flu')?
There are many subtypes of avian influenza viruses, most of which do not cause clinical disease in birds. H5N1 is the subtype that has caused clinical disease outbreaks in birds in Asia, Europe, the Middle East and Africa since 1996. These outbreaks have also been associated with sporadic, severe and fatal human cases.
No cases of H5N1 have been reported in birds or humans in Australia.
How could H5NI spread to Australia?
The H5NI avian influenza (AI) subtype could enter Australia through illegal importations of birds and/or their products. It may also be introduced accidentally by visitors (either on contaminated clothing if they have been working with infected poultry, or if they have contracted the virus themselves). Migratory wild birds could also bring H5N1 to Australia.
What is the chance of migratory birds bringing H5N1 to Australia?
The risk is generally regarded as quite low. Ducks and geese are the recognised spreaders of the avian influenza (AI) virus, but Australian ducks and geese are not migratory and rarely leave the continent. Since the emergence of the disease in Southeast Asia in 1997, and despite the abundance of migratory birds visiting our shores every year, Australia remains free of H5N1. Other countries on the Australian migration route like NZ, New Guinea, Taiwan, and the Philippines also remain free. The scientific data indicates that the Australian outbreaks of AI were not spread by migratory birds.
What is NSW doing about possible avian influenza outbreaks in poultry?
The level of biosecurity has been upgraded on commercial poultry farms in NSW to minimise the risk of exposure to risk factors like wild birds, contaminated water supplies, other animals and visitors. The poultry industry in NSW has been closely cooperating with NSW DPI to develop early reporting systems for unusual mortalities. NSW has extensive animal disease surveillance programs that ensure early detection of diseases. A network of private veterinarians, district veterinarians and diagnostic laboratories across NSW enable early diagnosis and effective response if an outbreak occurs.
Can anything be done to control avian influenza in wild birds?
No. The control of avian influenza in wild birds is not feasible. It is important to prevent outbreaks in commercial poultry farms because these birds could multiply the virus dramatically and the virus could spread further. It is essential to minimise possible contacts between domestic and wild birds.
Can birds be vaccinated against avian influenza?
The avian influenza vaccine is not readily available and its use will only be considered in an outbreak situation as part of the control and eradication strategy. There are significant limitations associated with vaccination against avian influenza. The vaccine can prevent clinical signs of disease, but birds can still be infected, shed the virus and spread infection. Vaccination may also lead to problems identifying birds that carry the virus, but do not show clinical signs because of the protection by the vaccine. In outbreak situations, vaccination could be considered in order to slow down the spread or to protect rare valuable birds in zoos and parks.
Is there any food safety concern associated with avian influenza?
No. Poultry products (meat and eggs) that have been property cooked are safe for human consumption as the cooking process destroys the avian influenza virus. Nevertheless, it is prudent for consumers to take normal food safety precautions when preparing and cooking poultry products.
Further information on food safety is available at the NSW Food Authority.
Can pet birds get avian influenza?
Yes. The majority of birds are susceptible to avian influenza and pet birds are no exception.
How do I protect my aviary birds or backyard birds?
Basic biosecurity steps will minimise the risk of avian influenza as well as other diseases. Health monitoring and sound husbandry practices assist in early detection of any flock problems. Purchase birds from reputable sources. Where possible, minimise contact between domestic and wild birds or other animals. Minimise non-essential visitors contact with domestic and aviary birds. Keep new flock introductions separately for 2-3 weeks after arrival. Water supply in most backyard or aviary flocks is chlorinated town water. Water from a dam, river or creek should be chlorinated to make it safe to drink.
What is an influenza ('flu') pandemic?
An influenza pandemic is a worldwide outbreak of disease that occurs when a new influenza A virus appears in the human population causing serious illness and which is able to spread easily from human-to-human.
Further information is available at NSW Health.