Issue 4, 13 March 2025
The detection of the H7N6 strain of high pathogenicity avian influenza (HPAI) at Hillgrove Farm in early December last year prompted a rapid response from MPI, Mainland Poultry and industry.
Our readiness work with the poultry and egg sectors, Department of Conservation and health agencies to prepare for HPAI H5N1 meant we were in a good position to deal with the less virulent H7N6 strain found on this farm.
We acted quickly to put strict biosecurity controls in place at the farm to prevent any possible spread. All chickens on the farm were humanely culled.
Extensive testing and monitoring of chicken farms linked to the Hillgrove property was carried out. A final round of testing on 22 December, involving 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, give us confidence that this virus has been contained to just the one property.
Cleaning and disinfection (C&D) operations at Hillgrove Farm are progressing well. The size of the site and the complexities of cleaning the type of free-range sheds on the property means this has been a huge undertaking for Mainland Poultry, MPI and our contractor NZ Biosecurity Services Ltd.
Each shed must be cleaned of all waste, with a mixture of jet washing, hot washing, sanitisation and fumigation, along with drying periods and then inspections. Once C&D is complete, a stand-down period of 28 days will apply before poultry can be re-introduced to the sheds.
Grass in the free-range areas of the property also needs to be managed. This requires cutting and baling the grass, treating the underlying soil with lime to reduce the risk of live virus persisting in the soil, and fallowing.
This has been a significant and complex response that would not have been possible without the partnership approach between MPI, Mainland Poultry and the Egg Producers Federation, the expertise of industry and the support of the wider sector.
What we have learned from this response will help inform our readiness work for H5N1 clade 2.3.4.4b. H5N1 2.3.4.4b is a much more virulent strain of HPAI.
Our webpage on the response has more information, including a detailed epidemiological report on the detection of H7N6 and the response at the Hillgrove property.
Trade implications of the H7 detection
Immediately following the detection in Otago, we suspended certification of live and raw poultry commodities to markets requiring freedom from HPAI.
Since then, we have been engaging with relevant trading partners to provide updates on stamping out H7N6 and discuss ways to reopen trade. While there are common elements across markets, solutions are agreed with each country.
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. Most recently, we have reopened access for trade in day-old chicks and hatching eggs with Malaysia worth around NZ$25 million.
HPAI is not a food safety concern
A key focus of our response to the H7N6 detection in Otago was to reassure New Zealanders that eating thoroughly cooked eggs and poultry products remains safe, even during a bird flu outbreak.
New Zealand Food Safety (NZFS) published advice on food safety, reiterating that there is no evidence that people can be infected with avian influenza by eating thoroughly cooked eggs or poultry (like chicken, turkey, or duck), or foods that contain them.
You can find this advice on our website:
www.mpi.govt.nz/dmsdocument/66309-Food-safety-advice-during-bird-flu-outbreaks-Fact-sheet
If HPAI H5N1 is detected in New Zealand, NZFS will issue updated advice through the MPI website.
Connecting with local government
Local government will play a key role in any response to HPAI H5N1. MPI is working closely with Te Uru Kahika (Regional and Unitary Councils Aotearoa) to coordinate and connect with territorial local authorities on H5N1readiness. At the same time, MPI and the Department of Conservation (DOC) are continuing to engage with local government at the regional and district level.
DOC recently ran a Rotorua Lakes regional tabletop exercise for HPAI, attended by representatives from local councils, NGOs, Treaty partners, health agencies and MPI. The aim was to define how cross-agency resources will be deployed at an operational level under various scenarios. The session was very constructive, with a strong sense of local ownership and collaboration.
It followed a national tabletop exercise in August last year involving One Health partners MPI, DOC and health agencies with representatives from Northland, Auckland and Waikato Regional Council. More regional tabletop exercises are being planned.
DOC and MPI staff also recently attended a hui hosted by Waikato Regional Council, involving representatives from a range of groups including local councils, Treaty partners and community organisations.
HPAI detections overseas
In Australia, Agriculture Victoria has confirmed HPAI H7N8 at four poultry properties in northern Victoria. This strain is different to the strains that impacted Australian poultry farms during 2024.
The United States (US), Europe and the United Kingdom are experiencing increasing outbreaks of H5N1 in poultry. This increase in outbreaks during the northern hemisphere winter is only to be expected in a seasonal disease that is spread by migrating wildlife.
The US also continues to experience outbreaks in dairy cattle following an initial spillover event in 2024. Although HPAI is not a cattle disease, the H5N1 strain of the virus has been detected in dairy herds in multiple states. Further spillover events are likely to be detected through the enhanced surveillance that is being implemented in the US as part of its national milk testing strategy.
We consider that, if this strain of HPAI did arrive in New Zealand, the risk of transmission from birds to cattle or other livestock is low. This is because the US is the only country that has reported spillover to cattle worldwide, despite large seasonal avian outbreaks of this strain in other northern hemisphere countries, and because our production system is quite different from the US.
A new science report has confirmed that H5N1 has spread to the Indian Ocean sub-Antarctic archipelagos of Crozet and Kerguelen. In October 2024 the virus was detected in dead southern elephant seals, king penguins, gentoo penguins, brown skuas and kelp gulls.
MPI remains in close contact with our colleagues overseas and we are monitoring all developments with this disease.
H5N1 infections in cats
There have been several recent reports from the US about cats becoming infected with H5N1 after eating raw pet food containing contaminated poultry.
We have known for some time that cats are susceptible to the H5N1 virus. Feline cases overseas have been linked to poultry or wild bird exposure, consumption of contaminated raw pet food and more recently after drinking raw milk from infected dairy cattle.
Avian influenza viruses are sensitive to heat treatment, meaning that it is safe to eat properly handled and cooked poultry meat and eggs, pasteurised milk and milk products and cooked beef. This extends to cooked pet foods such as cooked dog rolls, canned food and kibble.
As part of our readiness work here in New Zealand, New Zealand Food Safety is preparing a risk assessment of HPAI for raw pet food, so we can consider and mitigate any potential risks.
Spillover to humans
There have been further reports of HPAI H5N1 detection in humans, associated with known H5N1 outbreaks in poultry and dairy cattle. Avian influenza generally only spreads to people who have had a lot of close contact with infected birds or other infected animals. It appears that, in at least some of the cases reported recently, inadequate personal protective equipment (PPE) played a role in the spread to humans.
Strong biosecurity is essential to stop the spread of this virus to domestic birds, humans and other mammals. This means appropriate use and disposal of PPE, relevant to your context. Here in New Zealand, government agencies have been working with industry to develop health and safety guidance for people whose work brings them into contact with wild birds or poultry, including advice on appropriate PPE, depending on the level of risk.
We expect to include a link to the guidance in our next newsletter.
The Cabinet paper outlining the One Health approach to HPAI H5N1 and supporting documentation have been published on MPI’s website:
You can find them either by using the filter at the top of the page (search on HPAI) or scrolling down the page and looking for ‘One Health Response Approach to Highly Pathogenic Avian Influenza – Cabinet paper’.
Resources
Information and advice on HPAI, including planning and surveillance for H5N1 – MPI: www.mpi.govt.nz/HPAI
‘Bird flu, be ready’ information for backyard and pet bird owners – MPI: www.mpi.govt.nz/bird-flu
Information on the latest situation in the United Kingdom – UK Govt: www.gov.uk/government/news/bird-flu-avian-influenza-latest-situation-in-england#latest-situation
Information on the latest situation in the US – CDC: www.cdc.gov/bird-flu/situation-summary/index.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fbird-flu%2Fphp%2Favian-flu-summary%2Findex.html
Information on the outbreak in Victoria, Australia – Agriculture Victoria: https://agriculture.vic.gov.au/biosecurity/animal-diseases/poultry-diseases/avian-influenza-bird-flu
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