Avian influenza (AI) - questions and answers
What is Avian Influenza?
Avian Influenza is a highly infectious viral disease that can affect many species of birds, including commercial, wild and pet birds. Other names for Avian Influenza are bird flu, fowl plague and fowl pest. There are 144 subtypes of Avian Influenza virus in the A group of Avian Influenza viruses. These subtypes are differentiated by the presence of 2 proteins known as H and N.
Severe bird flu is caused by a few subtypes of Avian Influenza viruses in the 'H5' and 'H7' categories. The majority of avian influenza virus subtypes cause only relatively mild disease or sub-clinical infections in birds and poultry.
One of the subtypes is H5N1. This is the subtype involved in recent outbreaks of Avian Influenza in SE Asia and more recently in some areas of Eastern Europe.
What type of birds does Avian Influenza affect?
Avian Influenza can infect a very wide range of birds including chickens, turkeys, ducks, geese, quails, guinea fowl, partridges, pheasants, ostriches and a large number of aviary and wild birds especially waterfowl like ducks, geese and swans. AI virus has been isolated from 90 species of wild birds including sea birds, waders, herons, ibis, pelicans, cormorants, coots, moorhens, grebes, psitticines (parrots), swallows, sparrows, finches, doves, pigeons and emus. The disease can also affect a large variety of aviary birds.
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 clinical signs including breathing difficulties, coughing, swollen heads, dark comb and wattles, depression, drop in egg production, changes in egg shell colour, loss of appetite, decreased feed intake and decreased vocalization. Nervous signs like tremors of the head, unsteady gate, twisted necks and other unusual positions of the head and body sometimes occur.
Has Australia ever had an outbreak of Avian Influenza?
Australia had five outbreaks of Avian Influenza in chickens between 1976 and 1997. The outbreaks were in Victoria (3), Queensland (1) and NSW (1). All the outbreaks were contained and successfully eradicated withno impact on human health. They were not caused by the H5N1 strain. They were all from an 'H7' strain.
What is H5N1 bird flu?
There are many strains of Avian Influenza viruses. Most of them do not cause disease. The strain that is currently causing widespread disease in Asia and parts of Europe is the H5N1 strain. This strain is not present in Australia.
Are there any Avian Influenza viruses present in Australia?
Yes. Some strains 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 strains are continuously circulating among some populations of wild birds in Australia.
How could H5NI spread to Australia?
The H5NI strain could enter the country through illegal importations of birds and 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 the virus themselves). Migratory wild birds could also bring it 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 virus but Australian ducks and geese are not migratory and rarely leave the continent. Since the emergence of the disease in SE Asia in 1997, 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. Although Australia has had five outbreaks of Avian Influenza, the scientific data indicates that the outbreaks were not spread by migratory birds.
How has Avian Influenza spread in SE Asia?
The World Health organisation (WHO) has identified the main mechanism of transmission in SE Asia to be movements of captured or domestic live birds, local bird markets, trans-boundary trading in birds and bird products, movements of equipments, movements of people as well as interactions between local wild water birds and domestic poultry. The density and methods of raising domestic poultry in some of the affected countries as well as the unsuccessful attempts to eradicate the disease from poultry flocks are crucial factors contributing to the widespread nature of the disease in Asia. Migratory birds appear to have played a role in the spread of bird flu to Europe.
Why is there so much concern about the current outbreaks in SE Asia and Europe?
At present, the H5N1 strain is a disease of birds and poultry. If humans become infected from handling infected birds, they don’t pass the disease on to other humans. But, there is a concern that the H5N1 virus may change to a virus that is easily transmissible between people and capable of causing disease in humans, birds and other animals. While this is a possibility, it has been circulating in some of the most densely poultry and human populated areas of the world for up to nine years and up until now it has only affected a few individuals. Those affected have had a close association with infected poultry. There is no evidence of the virus being able to spread easily between humans. In its present form H5N1 is not capable of massive spread to humans and infection in humans occurs rarely and primarily as a result of close contact with infected poultry.
What is NSW doing about possible Avian Influenza outbreaks in poultry?
The level of biosecurity has been upgraded on poultry farms in NSW to minimise the risk of exposure to risk factors like wild birds, contaminated water supplies, other animals and humans. Contingency plans have been developed over many years to minimise the impact of an outbreak through early detection and early appropriate response. The poultry industry in NSW has been closely cooperating with NSW DPI to develop early reporting systems for unusual mortalities.
For much of the year, training exercises have been held around Australia to increase the capacity of Governments and Industry to respond to an outbreak in Australia.
NSW has extensive animal disease surveillance programs that ensure early detection of diseases. A net work of field veterinarians and diagnostic laboratories across NSW enable early diagnosis and effective response if an outbreak occurs.
Once the disease is present how is it spread?
Avian Influenza can be spread by movements of infected birds (domestic or wild), through droppings and secretions of infected birds directly or through contaminated objects, clothing or vehicles. Windborne spread from infected large flocks is also possible over short distances. Other animals like cats or dogs could also spread it if they come in direct contact with contaminated materials or infected birds.
Can anything be done to control Avian Influenza in wild birds?
The control of Avian Influenza in wild birds is not feasible. It is important to prevent outbreaks in commercial poultry premises because they could multiply the virus dramatically and the virus could spill over into local wild bird environments. Thus, it is essential to minimise as much as possible, contacts between domestic poultry or domestic birds and wild birds.
If H5N1 is found in wild birds there is no intention to initiate any mass culling of wild birds in Australia. The control of Avian Influenza in wild birds is not feasible and ineffective in prevention of further spread.
In an instance where when it is believed that the infection in wild birds is a recent spread from another source (eg a poultry farm) and the numbers are small and concentrated around an identifiable source, culling of wild birds in a limited area maybe contemplated.
Can it be eradicated?
Avian Influenza can be eradicated from poultry farms. On all occasions when it was found in Australia in poultry, it was successfully eradicated through slaughter of infected birds, disinfection of premises, surveillance in the area and movement controls of all domestic birds. The last outbreak in Australia was recorded in 1997 in a flock of commercial chickens in NSW.
Is Avian Influenza notifiable in NSW?
Notifiable disease means that if the disease is suspected or diagnosed in NSW, DPI must be informed of the case. Avian Influenza is a notifiable disease and if anyone suspects Avian Influenza in birds it should be reported to the Department of Primary Industries directly or on the Emergency Animal Disease Hotline 1-800-675-888.
Can birds be vaccinated against Avian Influenza?
The vaccine is not available off the shelves and its use will be considered in an outbreak situation as part of the control and eradication strategy. There are significant limitations associated with vaccination against this disease. The vaccine is capable of protection against disease but not against the birds becoming infected and shedding the virus. The vaccine will reduce the level of shedding but this reduction may not be sufficient to prevent further spread from the vaccinated birds. It may lead also 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.
How do you know that wild birds in Australia do not have the bird flu?
Bird flu (H5N1) is known to produce a variety of clinical signs in a wide range of wild as well as domestic birds. If H5N1 were to enter Australia, there will be lots of birds found dead in a confined locality, a "die-off". Australia has not experienced any such cases caused by bird flu. Government laboratories receive many samples from individual wild bird mortalities and investigations of suspect cases have been negative.
Surveys of wild birds over the years in many parts of Australia have not found any indication of exposure among wild birds or domestic birds to this virus. Current on-going surveys are also not indicating the presence or exposure of birds in Australia to H5N1. Following the recent spread to Asia and Europe the level of surveillance of wild birds in Australia has been increased.
Is the increased level of surveillance of wild birds an indication that Australia is at a greater risk than before?
The risk status has not changed. It is still believed that Australia is at the lower end of the risk scale. However, it makes good sense to monitor certain sites where migratory birds interface with Australian wild water birds to obtain early intelligence on the presence of the disease in the country.
How do I protect my aviary birds or my backyard chooks and ducks?
While the disease is not present in Australia and although in previous outbreaks in Australia backyard flocks remained free of the disease, it is recommended to introduce basic steps to minimise the risk of this disease as well as other diseases. Health monitoring and sound husbandry are an important perquisite for early detection of a problem in a flock. Birds should be purchased from reputable sources.
Additionally it is recommended that backyarders where possible minimise the contact between the domestic birds and wild birds or between their birds and other animals. It is a good idea to minimise non essential visitors contact with poultry or aviary birds. New introductions to a flock should be kept separately for 2-3 weeks after arrival.
Water supply in most backyard or aviary flocks is chlorinated town water. If dam, river or creek water is used it is advisable to ensure that the drinking water to the birds is safe by chlorinating the water.
How should water be chlorinated?
Too much chlorine could be detrimental to the health of the birds. In chickens levels above 3ppm can result in poor egg production and other health problems. The amount of required chlorine is influenced by the quality of the water and levels of organic matter in the water. Dam water may require 5ppm (5 mg in 1 litre of water or 5 grams in 1000 litres of water) to neutralise viruses such as Avian Influenza. Too little chlorine will not be effective in the prevention of spread of organisms from contaminated water. The contact time required to exert the killing effect is also important. At least 1 hour at levels of 5ppm is required to be effective on dam water. To achieve this, the water and chlorine solutions should be mixed in a settling tank. This allows both the settling of organic matter and suspended soil as well as sufficient contact time and appropriate reduction in chlorine levels to avoid toxicity to the birds. The level of chlorine in the water should be monitored regularly.
How are you going to guarantee the safety of workers who may help in destruction/disposal/decontamination of infected farms?
People working on farms infected with Avian Influenza will be given appropriate protective clothing, anti-viral drugs and be under medical supervision to eliminate the health risk as far as is possible.
Dead birds - should they be reported?
The occasional dead bird is found in most bird enterprises occasionally and a dead bird is not a cause for alarm. The death of a bird in an aviary or small poultry holding should be investigated by your private veterinarian as part of routine good management. Unusual clinical signs or unusual mortality involving more than one bird or protracted unexplained death in a flock of birds should be reported to your veterinarian or to NSW DPI and investigated. Multiple deaths of birds in a neighbourhood should also be reported. It is particularly important to report an incident if large number of dead birds is found in close proximity to large lakes, rivers and dams. Generally, with H5N1 following exposure of birds to the virus, multiple deaths can be expected within a short period of time. It may involve birds from one or multiple species of birds.
It is useful to remember that wild bird die-offs are commonly caused by poisoning and some other diseases. The location, the time, season etc could provide valuable clues as to whether poisoning from, for example botulism, is the cause or whether Avian Influenza is involved.
If I report wild dead birds can I be guaranteed that they will be picked up?
Not necessarily. An experienced veterinarian will assess the details of each case. Further investigations may follow if necessary. Specific instructions will be given to the person reporting the dead birds with respect to collection and where applicable also instructions on storage and handling of the dead birds.
Exposure to pigeons and their excrement - is it dangerous in terms of bird flu?
Pigeons in Australia have not been identified to carry bird flu but they can become infected. Pigeons can be infected with other organisms that pose a risk to humans but, again, there are no recorded cases of these diseases associated with wild pigeons. In the 5 outbreaks of Avian Influenza in Australia, pigeons were not involved in the spread of the disease and no evidence was found in pigeons around the infected areas.
Can pet birds get AI?
Yes, most birds are susceptible to AI and pet birds are no exception.
Is it safe to keep pet chickens in Australia?
Pet chickens like other pets could also carry some infections that affect humans. For example, Ornithosis/Chlamydia. The transfer of diseases between pet chickens and humans is rare and generally it is safe to keep pet chickens. Usual common sense hygiene should be in place to avoid risks of disease transmission between pets. Even if Avian Influenza was present in Australia the chances of a few pet chickens being exposed to Avian Influenza virus are very small. Further steps could be taken to further reduce the risk of exposure of pet birds to Avian Influenza. If the disease becomes widespread in a certain area the risk of exposure to the disease could lead to further assessment of the risk.
Travelling overseas to locations with bird flu and returning to Australia from those countries - what precautions need to be taken?
On return to Australia if such locations have been visited, Australian Quarantine and Inspection officers based at Australian ports should be notified.
If you have been in contact with live poultry in Asia, you should avoid visiting poultry premises in Australia for seven days after returning.
Industry practice is that people working on poultry farms should stay away from live birds for at least one week on return.
If you have simply recently visited a country that has had bird flu outbreaks, but not had any contact with wild birds or poultry, you should inform the manager of the poultry farm you are intending to visit. You should have a complete change of clothing before visiting poultry premises and will need to comply with any biosecurity plan in operation at the premises.
If you have birds at home, a complete change of clothing and shoes is advisable. It is advisable also to try and stay away from your own birds or other birds for at least 7 days.
What is an Influenza (or flu) pandemic?
A flu pandemic is a world-wide outbreak of disease that occurs when a new Influenza A virus appears in the human population, causes serious illness and is able to spread easily from person to person.
Is a flu pandemic different to the flu that occurs every year?
Yes. The seasonal outbreaks or ‘epidemics’ of flu that occur each year are caused by subtypes of Influenza viruses that are already circulating among people. This means that there is already a level of immunity in the community. Because we know or can predict which viruses are circulating each year, we can also vaccinate people for it. Pandemic flu is caused by an entirely new virus subtype. Because it is a new subtype, no-one in the community will have immunity to it. The pandemic can spread very quickly before a vaccine becomes available, affecting a greater number of people and likely causing greater sickness and death than a seasonal outbreak of flu.
Is the bird flu going to cause a flu pandemic?
Bird flu or Avian Influenza is an infectious disease of birds caused by type A strains of the Influenza virus. There have been a number of outbreaks of bird flu recently in Asia and isolated cases in Europe. There have also been some cases of people catching bird flu as a result of close contact with sick poultry. Because the bird flu virus has infected a small number of people, it is being closely watched in case it undergoes genetic changes making it able to spread easily from person to person. If these changes occur, then it would cause a pandemic. So far, this has not occurred. Organisations such as the World Health Organization and the Australian Government are concerned that this may happen in the future.
Is 'bird flu' or 'pandemic flu' in Australia?
No. There are no current reports of bird flu in animals or humans in Australia. A truly pandemic virus has not emerged yet, so is not present anywhere in the world.
What is the current level of threat of a pandemic in the world?
A close watch is being kept on the bird flu outbreaks. An expert group in Australia met at the end of May 2005 and determined that the threat level is Overseas 3. This means there are some human bird flu cases overseas but the infection is limited and doesn’t appear to be readily passing from human to human. A pandemic would be declared if we reached Overseas 6 - that is, when there is increased and sustained transmission of human bird flu in the general population.
How does pandemic flu spread?
Pandemics of flu are spread from person to person by respiratory secretions in three ways:
- Through spread of droplets from one person to another (eg coughing, sneezing).
- By touching things that are contaminated by respiratory secretions and then touching your mouth, eye or nose.
- Through spread of particles in the air in crowded populations in enclosed spaces.
How will I know if a pandemic has reached Australia?
The National Incident Room, situated in the Australian Government Department of Health and Ageing, is closely monitoring the situation overseas. Australia has a robust surveillance system and strong measures in place at international borders to give us maximal warning of the pandemic reaching Australia. If a pandemic occurs, it will be announced by the Minister for Health and Ageing and Australia’s Chief Medical Officer. The Department’s communications strategy for informing the public about the level of threat and the action that needs to be taken (including by individuals) will be stepped up.
What are the symptoms of pandemic flu?
The symptoms of pandemic flu are the same as the seasonal flu virus. For example, sudden onset of high temperature, muscle aches and pains, tiredness, cough, sore throat and stuffy or runny nose.
How long do symptoms take to develop and how long do they last?
It may take 2 to 7 days to show symptoms when you catch the flu and the symptoms may last for up to a week.
Who is at risk from pandemic flu?
A pandemic flu virus that emerges will be a new one that the entire population has no immunity to. Therefore, potentially all age groups will be at risk, but it is difficult to predict in advance who will be most severely affected. Previous pandemics have affected different age groups and have had varying death rates.
Can pandemic flu kill people?
Yes. However, there are treatments available and ways to prevent infection from occurring in the first place. All national and state and territory health authorities have strategies in place to reduce the spread and impact of the pandemic in the population.
How is pandemic flu treated?
The mainstays of treatment include rest, ensuring adequate fluid intake and nutrition and taking medications to help with fever and pain such as aspirin (but not in children) and paracetamol. Complications, such as bacterial pneumonia, can develop in some people and can be treated with antibiotics. Those who are severely affected may need hospitalisation, supplemental oxygen therapy and respiratory support through artificial ventilation.
What about antiviral medications?
The effectiveness of antivirals in the treatment of pandemic Influenza is unclear. The Australian Management Plan for Pandemic Influenza provides for some limited use for management of cases and contacts. However, in the event of a pandemic these medications will be in short supply. The Australian Government has developed a significant stockpile of the antivirals which will be used for prevention and treatment with the aim of minimising the overall sickness and death in the population.
How can I protect myself and others from pandemic flu?
Apart from the Influenza antivirals, there are many measures that individuals can take to protect themselves and others from all respiratory diseases, including pandemic flu.
- general hygiene measures such as regular hand washing;
- cough hygiene (turning away from other people and covering the mouth with tissues when coughing or sneezing, disposing of the tissues afterwards and washing hands after disposal of the tissues);
- when unwell, avoiding public places and contact with children or people with underlying illnesses;
- when attending a medical practice, alerting the receptionist to your symptoms so you can be seated away from others and possibly be given a surgical mask; and
- maintaining good general health and staying up-to-date with the recommended vaccinations, such as the pneumococcal and seasonal flu vaccine for those in high risk groups (see below for further information about vaccines).
What about vaccines during a flu pandemic?
The seasonal flu vaccine will not protect against pandemic flu. However, in the lead up to a pandemic, it will still be important to vaccinate high risk groups against any seasonal strains of flu which are currently circulating. The pneumococcal vaccine is also important for the elderly, as it can prevent secondary bacterial pneumonia, caused by the pneumococcal bacteria. Your GP can give you further advice about whether you should receive these vaccines and there is information available on the Department of Health and Ageing’s website. The Australian Government has signed contracts with 2 vaccine manufacturers to ensure that enough pandemic vaccine for all Australians will be produced during the event of a pandemic. However, the vaccine may take at least 3-6 months to produce, and initially will be in short supply. Therefore, priority groups are being determined in conjunction with Influenza experts. Once sufficient pandemic vaccine has been produced, all Australians will be able to receive the vaccine.
Is pandemic flu a quarantinable disease?
Yes. Highly pathogenic Avian Influenza affecting humans was made a quarantinable disease on23rd March 2004.
If I get pandemic flu will I be put in quarantine?
Depending upon the severity of disease, people who have symptoms of pandemic flu will be advised to stay at home or will be cared for in hospital (in isolation from other patients without pandemic flu.) Depending on the timing and severity of the pandemic outbreaks, quarantining of contacts (i.e. family or friends) of pandemic Influenza patients may occur, usually in the home. Quarantine or isolation measures may be used to help stop pandemic flu coming into Australia, as well as keeping it contained in the event the pandemic has arrived in this country.
How long would people be quarantined for?
Based on the current bird flu strains, individuals may be quarantined for 7 - 10 days. This will need to be reviewed according to the characteristics of the pandemic virus itself.
How well prepared is Australia for pandemic Influenza?
Australia is comparatively well prepared to respond to a flu pandemic. Quarantine officers are maintaining a high level of alert for birds and bird products from bird flu affected countries. The Australian Government has extensively stockpiled drugs and equipment needed in a pandemic - such as antiviral agents, personal protective equipment, and negative pressure units needed to isolate hospital rooms to prevent flu spread and thermal scanners to screen people with signs of flu at the borders. The Government has also contracted with two vaccine producers to ensure sufficient pandemic vaccine will be available for all Australians.
Other measures include enhancing the national infectious diseases surveillance system, improving laboratory capacity in developing countries in the South East Asia region and developing an independent WHO Collaborative Centre for Reference and Research on Influenza. To date, the Australian Government has invested $156.8 million in preparing for a pandemic.
If H5N1 bird flu did occur in Australia, would it be safe to eat chicken meat and eggs?
Yes. Bird flu is not present in Australia and, if it ever did appear, diseased poultry or eggs would not be allowed to reach the market. They are destroyed as part of eradication campaigns. Close surveillance is placed on poultry or egg layer farms and if any sign of illness develops, they are put in quarantine prior to the disease being stamped out.
In any case, thoroughly cooking chicken meat and eggs would protect people from the virus, as it already does for other genuine food-borne diseases. Further information on safe preparation and cooking of poultry products is at www.foodauthority.nsw.gov.au
Can I get bird flu from handling or eating chicken or eggs?
There is no evidence that bird flu can spread through contaminated food. If the disease was detected in Australia, the chance of infected poultry entering the food chain would be extremely low. Nevertheless, it is prudent for consumer to take normal food safety precautions in the kitchen. The NSW Food Authority always recommends consumers follow a few simple food safety tips to minimise the risk of food-borne illness.
The World Health Organisation (WHO) also advises that poultry produces (chicken meat and eggs) that have been properly cooked are safe to consume.
The NSW Food Authority recommends the following practices, based on WHO advice, to reduce exposure to the virus. These are the same commonsense techniques used to destroy many common food-borne pathogens:
- Separate raw meat from cooked or ready-to-eat foods. Do not use the same chopping board or the same knife for raw meat and other foods. Do not handle both raw and cooked foods without washing your hands in between and do not place cooked meat back on the same plate or surface it was on before cooking.
- Keep clean and wash your hands. After handling frozen or thawed raw chicken or eggs, wash your hands thoroughly with soap. Wash and disinfect all surfaces and utensils that have been in contact with the raw meat.
- Cook food thoroughly. Thorough cooking of poultry meat will inactivate the virus. Either ensure that the poultry meat reaches 70°C at the centre of the product ("piping" hot) or that the meat is not pink in any part. Egg yolks should not be runny or liquid. Do not use raw or soft-boiled eggs in food preparations that will not be heat treated or cooked further.
- Do not eat raw poultry parts or raw eggs.
For further information see www.foodauthority.nsw.gov.au
Can I contract H5N1 from handling wild birds?
In Australia wild birds are not known to be carrying the disease. The risk therefore, currently, is very low. Wild birds can carry other diseases that can infect humans. To further minimise any risk, it is recommended that general hygiene precaution should be followed when handling wild birds. This includes not handling wild birds unless necessary, wearing disposable gloves and washing hands nails and forearms thoroughly with soap and water after handling dead birds or their carcases.
Can hunters contract H5N1 Avian Influenza from wild birds?
Recreational duck hunting is not permitted in NSW. Culling of pest birds is permitted under permits from (NPWS and/or Game Council). In such cases, the risk is extremely low as long as Australia remains free of the disease. To reduce the risk even further the following suggestions are common sense precautions that permit holders should follow normally when hunting:
- Do not handle birds that are obviously sick or birds found dead.
- Keep your game birds cool, clean, and dry.
- Do not eat, drink, or smoke while cleaning your birds.
- Use rubber gloves when cleaning game.
- Wash your hands with soap and water or alcohol wipes after dressing birds.
- Clean all tools and surfaces immediately afterward; use hot soapy water, then disinfect with a 10% chlorine bleach solution.
- Cook game meat thoroughly.
Can I contract other strains of Avian Influenza from wild birds?
In Australia infection of wild birds with other strains of Avian Influenza has been occasionally reported at a very low level. The strains found in wild birds in Australia are different from the strains involved in human cases in Asia. The spread of other strains of Avian Influenza to hunters has not been recorded.
What would happen if Australian chickens did get avian influenza?
Under the supervision of the NSW Department of Primary Industries, all birds on affected properties would be destroyed on-farm and disinfection and movement controls would be put in place to prevent the spread of the virus.