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Readying for avian influenza – update from the Ministry for Primary Industries

Published on 26 July 2024.

The Ministry for Primary Industries (MPI) has issued the first in a series of regular updates about high pathogenicity avian influenza (HPAI) and New Zealand’s preparations should it arrive here. Read the full update below.

Preparing for HPAI

New Zealand has never had a case of HPAI, but we have been preparing for avian influenza in one form or another since the early 2000s.

The HPAI strain of concern to New Zealand is H5N1, a strain being spread by the movement of wild birds in the northern hemisphere, and most recently to the Antarctic Peninsula.

Unlike many biosecurity threats, HPAI is not expected to be brought to New Zealand by human activity, but by migratory wild birds. If HPAI arrives in New Zealand via wild birds, it could spread to other wildlife or poultry by direct contact between infected and healthy birds, or through contaminated equipment and materials, including water and feed.

We know from the experience overseas that a ‘One Health’ approach to this disease is essential, so we’re working in partnership with the Department of Conservation, Ministry of Health and Health New Zealand | Te Whatu Ora to prepare for HPAI if it arrives here.

Improving on-farm biosecurity now is going to be an essential first line of defence against HPAI.

The implementation of rigorous on-farm biosecurity in New Zealand now, before HPAI arrives, has the potential to protect individual farms from infection and to limit impacts on the domestic supply of poultry meat and eggs.

MPI is working in partnership with the Poultry Industry Association of New Zealand and the Egg Producers Federation to strengthen the industries’ business continuity and resilience in the event of an outbreak of HPAI. We are talking with industry to understand what operators and farmers are already doing as part of their usual risk management activities, and what else is needed. This work will support poultry meat and egg farmers to have robust biosecurity plans in place, and support the wider industry to be prepared. We’ve developed a joint newsletter with industry bodies to share the latest HPAI information with their poultry and egg producers. You can find the newsletter here.

We’ll continue to update you on our preparations for HPAI through this newsletter, our website and social media. Go to www.mpi.govt.nz/HPAI to see the latest information and resources.

Food safety assurance

MPI’s website provides accurate information about the safety of egg and chicken products.

The new Avian influenza, food safety and human health page explains that HPAI is not a food safety concern and these products are safe to eat:

  • properly handled and cooked poultry meat, eggs, and egg products
  • pasteurised milk and milk products
  • cooked beef.

This is because avian influenza viruses are sensitive to heat treatment, so even if we had HPAI in New Zealand, thoroughly cooked food and pasteurised milk products would be safe to consume.

Thorough cooking of poultry or foods that contain poultry or eggs means heating food to an internal temperature of:

  • 75°C for at least 30 seconds, or
  • 70°C for 3 minutes, or
  • 65°C for 15 minutes.

Australian outbreaks of HPAI H7 strains

The latest news from Australia is that HPAI H7 strains have been detected in commercial poultry at two farms in New South Wales (plus four additional detections on non-commercial properties), eight farms in Victoria and two sites in Australian Capital Territory (a poultry farm and backyard chickens).

New Zealand has never had a case of high pathogenicity avian influenza of any strain, despite previous outbreaks of the disease in Australia. There are strict measures in place at the border to prevent HPAI from entering New Zealand through cargo, air passengers or other imports, including poultry or egg products entering New Zealand.

Australia does not have the H5N1 strain that we are particularly concerned about. The H5N1 strain that has adapted to wildlife is being spread by the movement of wild birds, most recently to the Antarctic Peninsula. The HPAI H7 strains in Australia develop only in poultry, not wild birds (see below for more details on that).

The difference between the H7 strains detected in Australia and the H5N1 strain means we don’t need to be concerned about the threat of wild birds introducing HPAI from the current Australian outbreak to New Zealand.

The H5N1 strain that has emerged since 2020 is able to establish in wildlife and spread large distances with the movement of wild birds. This is the strain that has been detected in Antarctica and has been the focus of our preparedness.

In contrast, the strains detected in New South Wales and Australian Capital Territory (H7N8) and Victoria (H7N3 and H7N9) appear to have arisen in the traditional way, where low pathogenicity avian influenza (LPAI) in wild birds is transmitted to poultry, and then mutates to HPAI in the poultry. This is a chance mutation that doesn’t happen with each transmission of LPAI to poultry.

The H5N1 strain is different because the high pathogenicity strain is carried in wild birds and any transmission to poultry will result in HPAI. This infographic from the World Organsation for Animal Health illustrates this: 052314_WOAH Infographic V9

The Australian outbreaks of the H7 strains provide useful information on the way that HPAI has behaved over the past 30 years, and how it continues to behave in parallel to the H5N1 strain in wildlife.

See the latest updates from Australian states affected in these links:

Victoria

New South Wales

ACT

US detection of HPAI in dairy cows

Late last month, US authorities announced results from a second study of the effectiveness of pasteurisation of milk containing HPAI, using a process typically used by commercial milk processors. The intention was to further confirm that pasteurisation is effective at inactivating the virus in fluid milk and other dairy products made from pasteurised milk. The results of the second study confirmed the results of the earlier study, that the most commonly used pasteurisation time and temperature requirements were effective at inactivating HPAI H5N1 virus in milk.

The spread of HPAI H5N1 to dairy cows is the only known spillover to cows worldwide. Many other countries with this strain of the virus have not detected spillover to cows.

We don’t expect spillover to dairy cattle should HPAI H5N1 arrive in New Zealand, although we will need to remain vigilant for spillover events to any mammals. It’s likely that any spillover in New Zealand would be unique to our situation – for this reason we are working with vets and industry bodies to raise awareness of HPAI and potential signs in mammals.

Resources

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