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Avian influenza is a contagious viral disease that primarily affects domesticated and wild birds.
There are different types of the avian influenza virus. The 2 types of concern for New Zealand are:
- high pathogenicity avian influenza (HPAI), which causes severe signs and high death rates in birds
- low pathogenicity avian influenza (LPAI), which typically causes few or no signs in birds but can mutate to become HPAI.
New Zealand has never had HPAI. However, LPAI viruses exist in wild birds and have been detected in New Zealand.
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 historically known as "fowl plague" and is also known as "bird flu".
More information about avian influenza:
Tracking global outbreaks of HPAI
In 2021 and 2022, there were outbreaks of the H5N1 strain of HPAI in domesticated and wild birds across the northern hemisphere. In 2023, this strain began to appear in the southern hemisphere, including in South America and Africa.
Australia, New Zealand, the Pacific Islands, and Antarctica remain free from the H5N1 virus. However, historically, Australia has had outbreaks of different strains of HPAI in poultry, which have been successfully eliminated each time.
The Food and Agriculture Organization (FAO) – part of the United Nations – has information on avian influenza outbreaks globally.
Avian influenza is a zoonotic disease, which means there is the possibility it can spread to people, as well as other mammals. HPAI has been detected overseas in a variety of non-avian species, such as pigs, dogs, mustelids, and most recently several types of marine mammals. This spread from bird populations into mammals is termed "spillover". There is no evidence of spread of H5N1 between mammals or back to birds (called "spillback").
Globally, there are rare cases of human infection with avian influenza, generally when people have a lot of contact with infected birds. You can find out more on the New Zealand Ministry of Health and the FAO websites.
The risk for 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.
There is a risk that HPAI could arrive in New Zealand through infected migratory birds, infected people or contaminated items. It could then 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.
Biosecurity New Zealand is monitoring HPAI and the global situation, and has many existing systems in place to prevent HPAI entering New Zealand and to ensure early detection if it does arrive.
- 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 summer field surveillance programmes at non-migratory waterfowl sites with Fish & Game New Zealand
- monitoring and awareness with New Zealand's wildlife hospitals, poultry industry groups, veterinarians, and wildlife rehabilitation centres
- surveillance support and input from New Zealand's Wildlife Advisory Group
- 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 suspect human cases of HPAI
- support and collaboration with World Organisation for Animal Health and international partners in avian influenza working groups.
If HPAI is detected in New Zealand and/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.
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
- unusual or 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.
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.