Black billed gull
Image: Andrew Walmsley | ©

Avian influenza

Introduction

Avian influenza (also called bird flu) is a contagious viral disease that affects both domestic and wild birds and is caused by avian influenza viruses.

February 2024: Avian influenza advisory

Highly pathogenic avian influenza H5N1 (HPAI or bird flu) has spread globally since December 2021 but has not been detected in Oceania (Australia, New Zealand, Pacific Islands).  

Biosecurity New Zealand a branch within the Ministry for Primary Industries (MPI), is responsible for investigating and responding to any new pests and diseases arriving in New Zealand.

Biosecurity New Zealand has assessed the current risk of HPAI arriving in New Zealand as low. However it is closely monitoring the global situation, and the risk may increase as the disease spreads to regions where it has never previously been identified. 

New Zealand is lucky to be isolated from other land masses, does not have migratory waterfowl pathways, and we have good border biosecurity which will reduce the risk of arrival of HPAI. Biosecurity New Zealand has systems in place to prevent HPAI entering New Zealand through human activity and to ensure early detection if it does arrive. 

DOC is working closely with Biosecurity New Zealand to ensure we are prepared to manage the impacts on native species if the virus does arrive in New Zealand.

Monitoring of bird populations is part of DOC’s core work. We encourage anyone who sees three or more dead or dying birds, marine mammals or other wildlife to report it to Biosecurity New Zealand: 0800 80 99 66. 

Do not touch or attempt to move any dead or dying wildlife.

Avian Influenza - advisory for wildlife managers and bird banders January 2024 (PDF, 266K)

What is avian influenza?

Avian influenza is a contagious viral disease that affects both domestic and wild birds and is caused by avian influenza (AI) viruses.

Most wild birds infected with the virus are asymptomatic. Strains of this virus are classed as either:

  • low pathogenic (LPAI) - causing no or minimal illness
  • highly pathogenic (HPAI) - causing severe illness.

How is avian influenza spread?

Avian influenza is mainly spread by close contact between infected birds and healthy birds. It can also be transmitted when birds come in contact with environments, equipment or materials (including water and feed) that have been contaminated with faeces or secretions from the nostrils or beak of infected birds.  

This highly contagious viral infection can affect all species of birds both wild and domestic. Cases have also been seen in mammals associated with bird mortality events including seals and sea lions.

The transmission of avian influenza from birds to humans is rare but the World Health Organisation states HPAI in humans has a 50% mortality rate. People who are in close and repeated contact with infected birds or heavily contaminated environments are at risk of being infected with avian influenza.

What is the risk of avian influenza arriving in New Zealand?

HPAI has been spreading globally since December 2021 but has not been detected in New Zealand, Australia, the Pacific Islands.

New Zealand has never had a case of HPAI, but low-pathogenicity avian influenza viruses have been detected via surveillance in wild mallard ducks in the past.

If HPAI is detected in New Zealand, Biosecurity New Zealand is the lead agency and would coordinate any response with support from DOC and the Ministry of Health.

A variety of migratory shorebirds do return here and could bring avian influenza. The most numerous shorebirds are the bar-tailed godwit, red knot, ruddy turnstone and Pacific golden plover. The bar-tailed godwit flies directly from Alaska to New Zealand without stopovers. 

Other species may visit estuaries along the Asian coastline, the Philippines and Australia on their annual migrations south from arctic Russia.

Seabirds such as Arctic and pomarine skuas arrive every spring and summer from the Arctic region. Arctic tern, little terns and common terns are also regular annual visitors to New Zealand, and many species of pelagic seabirds breed here after spending winter feeding in the Pacific and Southern Oceans.

Vulnerable New Zealand wildlife species 

We don’t know exactly what impact HPAI would have on native species but, based on overseas evidence, it is likely to affect colony nesting birds such as red and black-billed gulls, gannets, terns and other seabirds.

This virus spreads rapidly through close contact. HPAI is transmitted between colony birds through secretions and faeces, and to predator/scavenger species such as raptors and marine mammals through exposure and consumption.

How can we protect our wildlife?

Management options are limited, bird flu in wild birds is not an eradicable disease. The best way to protect our native birds is to ensure there are strong, healthy populations at multiple locations. This means continuing, and where possible increasing, the great work done by breeding and predator control programmes. We also need to have strong biosecurity and quarantine practices.

Vaccination might be an effective way to protect some core breeding populations to prevent species extinction. It is not possible to vaccinate all our endangered birds, but we can focus on those species in captivity where the full two doses of vaccine can be given.

Vaccination requires two injections under the skin, one month apart. The Poulvac Flufend RG vaccine was developed overseas by Zoetis. The vaccine has been shown to be safe and effective in zoos in Europe.

Use of HPAI vaccines in New Zealand is prohibited. However, the Ministry for Primary Industries has granted approval for DOC to use this vaccine in a controlled trial to test its safety and efficacy in a select number of endangered native birds.

The trial is limited to a small number of threatened native species in specified captive facilities. It is being carried out under strictly controlled conditions by DOC. The vaccine being trialled in Aotearoa contains inactivated (dead) virus, meaning it cannot cause a bird flu infection.

Five species in the vaccination trial:

  • Takahē
  • Tūturuatu (shore plover)
  • Red-crowed kākāriki (as a surrogate for kākāriki karaka)
  • Kakī (black stilt)
  • Kākāpō

HPAI - Bird flu vaccination trial general factsheet (PDF, 771K)

HPAI is a notifiable disease and must be reported to MPI

Signs of HPAI vary but indicators include, sudden death, tremors, weakness, paralysis, difficulty breathing and diarrhoea.

Report groups of three or more sick or dying birds, marine mammals or other wildlife to the Biosecurity New Zealand Exotic Pest and Disease hotline: 0800 80 99 66.

Biosecurity New Zealand will take details and an incursion investigator will be in contact with you. Provide as much detail as you can, including:

  • Record a GPS reading or other precise location information.
  • Take photographs and/or videos of sick and dead birds.
  • Identify the species and estimate the numbers affected.
  • Note how many sick or freshly dead are present as well as total number present.
  • Follow Biosecurity New Zealand instructions for handling of sick or dead birds.

Further resources

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