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About avian influenza
Avian influenza is a contagious viral disease that primarily affects domesticated and wild birds, but is known to be transmissible to mammals.
There are 2 categories of avian influenza virus:
- high pathogenicity avian influenza (HPAI), which can cause severe signs and high death rates in birds
- low pathogenicity avian influenza (LPAI), which typically causes few or no signs in birds but can possibly mutate to become HPAI.
New Zealand has never had HPAI. However, LPAI viruses exist in wild birds and have been detected in New Zealand. Biosecurity New Zealand has an active surveillance programme for LPAI and tests around 2,000 samples from wild birds each year.
Types of HPAI viruses, like the current H5N1 circulating globally, can cause high mortality in poultry (chickens and turkeys), waterfowl (ducks, geese, and swans), shorebirds (godwits, stilts, and plovers) and seabirds (gulls and terns). HPAI in poultry is also known as "fowl plague" and "bird flu".
New Zealand's risk of HPAI
The risk of HPAI arriving in New Zealand is low because we:
- have strong border biosecurity
- are isolated from other land masses
- are not on a migratory pathway for waterfowl (while a few species of wild birds sometimes arrive from Australia, this only happens occasionally)
- have limited migratory shorebird pathways, and the likelihood of an infected bird making the journey here is small, due to the high mortality of HPAI.
New Zealand’s risk of an incursion of HPAI will change if the disease spreads in Antarctica towards the Ross Sea region, and we are carefully monitoring changes in the distribution of the virus.
If high pathogenicity avian influenza is detected in New Zealand or its territories, Biosecurity New Zealand will coordinate a response in partnership with the Department of Conservation and the Ministry of Health.
Biosecurity, surveillance, and response
In 2021 and 2022, there were outbreaks of the H5N1 strain of HPAI in domesticated and wild birds across the northern hemisphere, including the United Kingdom, Europe, and the United States. HPAI H5N1 has also been detected in non-avian species including a wide variety of mammals. In 2023, this strain began to appear in the southern hemisphere, including in South America and Africa, before being detected in the sub-Antarctic island of South Georgia in the South Atlantic Ocean in late 2023, and the Antarctic peninsula near South America in February 2024.
Australia, New Zealand, the Pacific Islands and much of Antarctica remain free from the H5N1 virus. We are actively monitoring disease spread and as more information about how the disease behaves comes to light in other parts of the world.
Early detection systems
We have many systems in place to prevent HPAI entering New Zealand on those pathways that can be managed, and to ensure early detection if it does arrive.
These include:
- biosecurity border checks for travellers coming into New Zealand who have had contact with poultry and/or wild birds, and for risk items and cargo
- the Biosecurity New Zealand Exotic Pests and Disease Hotline for reporting suspected cases: 0800 80 99 66
- annual sampling for LPAI in non-migratory waterfowl, in partnership with Fish & Game New Zealand
- monitoring and awareness with New Zealand's wildlife hospitals, poultry industry groups, veterinarians, and wildlife rehabilitation centres
- work with the Department of Conservation Te Papa Atawhai (DOC) on any suspected exotic diseases in wild bird populations, including native birds
- work with the Ministry of Health on any suspected human cases of HPAI
- support and collaboration with World Organisation for Animal Health and international partners in avian influenza working groups.
What we'll do if HPAI is detected
If HPAI is detected in New Zealand or its territories, Biosecurity New Zealand is the lead agency and will coordinate any response. Any actions, such as movement control, vaccination, or depopulation, would depend on the infected species and location.
We are working closely with the Department of Conservation and the Ministry of Health on a ‘one health’ approach to preparing for and responding to HPAI.
Avian influenza viruses in humans and other mammals
Avian influenza is a disease with potential for zoonotic spillover, which means there is the possibility it can spread to people as well as other mammals.
Overseas, HPAI has been detected in a variety of land-based and marine mammals, which can be infected with the disease after eating infected material from wild birds. In March 2024, HPAI was detected in dairy cattle in the United States, with cattle generally recovering from the disease following treatment.
Globally, there are rare cases of human infection with avian influenza, generally when people have a lot of contact with infected birds or mammals.
You can find out more on the New Zealand Ministry of Health and the Food and Agriculture Organization of the United Nations (FAO) websites.
Highly pathogenic avian influenza – Ministry of Health
Global avian influenza viruses with zoonotic potential situation update – FAO
How HPAI could arrive and spread
There is a possibility that HPAI could arrive in New Zealand through infected migratory birds. Once in New Zealand, it could spread by direct contact between infected and healthy birds, or through contaminated equipment and materials, including water and feed.
Although, historically, waterfowl are the most common hosts, shorebirds and seabirds have now been identified as hosts for HPAI. If avian influenza arrives in New Zealand, there is a risk it will spread from wild birds to domesticated birds, such as poultry, because properties with domesticated birds often border wildlife habitats and contact between poultry and wild birds is possible.
How to identify HPAI
Avian influenza signs vary, but with HPAI, the most obvious sign is several dead birds within a flock. As well as sudden mortality, signs for HPAI in poultry (chickens and turkeys) can include:
- lethargy or a reluctance to move
- reduced appetite
- droopy head, paralysis, or incoordination (neurologic signs)
- darkened or swollen face, comb, or wattle ("cyanosis") from lack of oxygen
- coughing, panting, and nasal secretions
- unexpected drop in egg production
- bruising or hemorrhages
- severe diarrhoea
- a silent or "too quiet" poultry shed.
In domesticated waterfowl, such as ducks and geese, HPAI generally has lower mortality and is, therefore, harder to detect. Signs are usually related to the nervous system, such as involuntary movement, lack of co-ordination, blindness, and trembling.
Signs in other species often kept in New Zealand, such as quail, guinea fowl, and pheasants, differ depending on the virus strain.
HPAI in backyard poultry and waterflowl fact sheet [PDF, 521 KB]
What to do if you suspect avian influenza
If you see sick or dying birds with signs consistent with HPAI, report it immediately to Biosecurity New Zealand's Exotic Pest and Disease hotline on 0800 80 99 66.
Sick or dead birds should not be handled. Our investigators will advise you on what action to take.
If your backyard poultry are unwell or there has been an unexpected death of several birds, contact your veterinarian first to rule out more common diseases.
Information that can be helpful for our investigators includes:
- an accurate location of the birds (GPS reading or other precise location information is ideal)
- photographs or videos of sick and dead birds
- an estimate of sick, dying, or dead birds
- any previously sick or recently dead birds.
Make sure you wait for instructions before handling any sick or dead birds.
Avian influenza in animals can only be diagnosed and confirmed through laboratory testing at the MPI Animal Health Laboratory.
Find out more about avian influenza
Bird flu and diseases – Poultry Industry Association NZ
Avian influenza and other wildlife diseases – DOC
Exotic diseases of Poultry: A review – Surveillance Magazine [PDF, 5.3 MB]
Find out about HPAI fowl plague – The Poultry Site
Avian influenza – World Organisation for Animal Health