A strain of bird flu (H7N6) in Otago

Media releases we issued on the H7N6 detection in Otago

No further signs of HPAI following detection at Otago

There continues to be no sign of high pathogenicity avian influenza (HPAI) outside of Mainland Poultry’s farm at Hillgrove, Otago, where the H7N6 strain of HPAI was detected in December 2024.

There remains no risk to eggs and chicken supply in New Zealand, given the size of the national flock. The risk to human health remains low and there are no food safety concerns.

The farm is being cleaned and disinfected and remains in lockdown

We acted quickly to put strict biosecurity controls in place at the farm to prevent any possible spread. The farm remains under strict biosecurity lockdown.

All chickens on the farm were humanely culled.

We carried out extensive testing and monitoring of chicken farms linked to the Hillgrove property. In December, testing of 4,300 samples from 36 flocks across 5 farms linked to Mainland’s Hillgrove layer property found no sign of HPAI.

Testing was timed to coincide with the end of the full incubation period for the virus. This, and the number of tests carried out, gives us confidence that this virus has been contained to just the one property.

Cleaning and disinfection of the farm is being carried out to ensure all traces of the disease have been removed.

What is HPAI H7N6 and how did it get here?

Avian influenza is a viral disease of birds found globally. Virus strains are described as low pathogenicity (LPAI) or high pathogenicity (HPAI).

The H7N6 strain is closely related to LPAI strains present in wild birds in New Zealand.

LPAI has been present in wild bird populations in New Zealand for decades and many species of wild birds may have strains of the virus. Internationally, over 5,000 species of wild birds have this type of avian influenza.

LPAI causes few or no signs of illness in wild birds. However, when a low pathogenicity strain of avian influenza is introduced to chickens, it can mutate into a high pathogenicity strain.

Testing indicates that the infection at the Hillgrove farm and happened after free-range laying hens foraging outside were exposed to the low pathogenicity virus from wild birds, which then mutated in the hens to become HPAI. This is the first time such an event in New Zealand has been documented.

There is no evidence that H7N6 has spread from chickens back into wild birds.

While this is a high pathogenicity strain, it is not the HPAI H5N1 strain that has caused deaths in poultry, wild birds, and mammals overseas. New Zealand remains free of HPAI H5N1.

Testing has confirmed the strain is unrelated to the H7 strain of avian influenza identified in Australia.

What is the impact on international trade?

Immediately following the detection, we suspended certification of live and raw poultry commodities to markets requiring freedom from HPAI and have worked to protect as much of New Zealand’s existing trade as possible.

We continue to make positive progress in resuming safe trade. For example, we reached agreement with Australia to continue the export of some poultry products, including chicken meat, dried pet food, and dog rolls that meet avian influenza heat treatment requirements, worth more than $50 million.

We’re in close contact with relevant trade partners. While there are common elements across markets, solutions are agreed with each country.

How we have been preparing for the arrival of bird flu

MPI has been preparing for HPAI for some time. International experience with avian influenza has shown us this particular strain can be eradicated quickly and successfully.

We are working closely with industry partners. We have put a lot of effort in with the poultry and egg sector, the Department of Conservation, and Ministry of Health to prepare for H5N1 and that puts us in a good position to deal with the less virulent H7N6 strain found on this farm.

Does this mean New Zealand is at greater risk of getting HPAI H5N1?

The H7N6 strain detected in Otago is different from H5N1. The detection of H7N6 does not change the likelihood or risk of the H5N1 strain arriving in New Zealand.

Biosecurity New Zealand and our partners have surveillance programmes in place to detect the arrival of HPAI and other exotic diseases.

While the HPAI H5N1 strain is still some distance from New Zealand, it’s important we take a cautious approach.

New Zealand has an advantage over many other countries that have experienced the H5N1 strain of HPAI, in that we have time to prepare.

Are wild birds a risk to poultry farms?

There is no evidence to suggest any recent change in the circulating LPAI viruses in New Zealand wild birds or that the risk of spread of LPAI from wild birds to poultry has changed.

However, changes in animal husbandry with more free-range birds does create the potential for increasing exposure of poultry to LPAI viruses carried by wild birds.

Good on-farm biosecurity and minimising the contact between wild birds and poultry is the recommended approach to protecting poultry from bird flu.

Signs of HPAI

Look out for signs of HPAI in chickens, turkeys, and domesticated waterfowl such as ducks and geese.

Chickens and turkeys

The most obvious sign is sudden death of multiple birds within a flock. As well as sudden mortality, signs for HPAI can include:

lethargy or a reluctance to move
reduced appetite
swelling around the head and neck
droopy head, paralysis, or incoordination (neurological signs)
darkened or swollen face, discolouration of wattles and combs
coughing, panting, and nasal discharge
unexpected drop in egg production
bruising or haemorrhages, especially of the legs
watery or green diarrhoea
a silent or "too quiet" poultry shed.

Domesticated waterfowl, such as ducks and geese

HPAI generally has lower mortality in waterfowl, so it is harder to detect. Signs are usually related to the nervous system, such as involuntary movement, lack of coordination, blindness, and trembling.

How to report suspected HPAI

If you see 3 or more sick or dead wild birds in a group, report it immediately to the exotic pest and disease hotline on 0800 809 966. Do not handle or move the birds.

Provide as much detail as you can, including:

a GPS reading or other precise location information
photographs or videos of sick and dead birds
species identity and estimate of numbers affected
note how many are sick or freshly dead, and the total number present.

We will take the details and an animal health specialist will be in contact with you. Follow any instructions from MPI for handling of sick or dead birds.