New Zealand Govt Statement on HPAI H7N6 Detection In Poultry

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Like everywhere else in the world, LPAI viruses circulate in Oceania. Most are considered innocuous to poultry and to humans, but when an H5 or H7 LPAI virus spills over from wild birds into poultry it can sometimes spontaneously mutate into an HPAI strain.

 

Often these HPAI outbreaks are limited to a single farm, but he virus can be inadvertently spread by moving birds, eggs, feed, equipment or personnel between farms. Less commonly, it may be picked up and carried to other farms by local or migratory birds.

Earlier this year we followed multiple outbreaks of HPAI H7 in Australia; (H7N3 & H7N9) in Victoria, and H7N8 in New South Wales & ACT (see map below).  No new outbreaks have been reported, however, since mid-summer.

With the exception of China's H7N9 epidemic, human infections with H7 viruses have been generally mild (with a few notable exceptions). They can be, however, very destructive and difficult to eradicate in poultry.

Overnight the New Zealand Ministry for Primary Industries  announced the detection of HPAI H7N6 on a poultry farm in Otego, on the South Island.  This appears to be the first reported HPAI outbreak in New Zealand. 

Initial tests indicate this outbreak is unrelated to the outbreaks in Australia earlier this year, and are likely the result of the above mentioned spontaneous mutation from an  LPAI -> HPAI virus.   

The full statement from the NZ MPI follows:

Strict biosecurity measures in place on chicken farm

Date: 02 December 2024

Biosecurity New Zealand has placed strict movement controls on a commercial rural Otago egg farm, after testing confirmed a high pathogenic strain of avian influenza in chickens that has likely developed from interactions with local waterfowl and wild birds.

"Tests from the Mainland Poultry managed farm have identified a high pathogenic H7N6 subtype of avian influenza. While it is not the H5N1 type circulating among wildlife around the world that has caused concern, we are taking the find seriously," says Biosecurity New Zealand deputy director-general Stuart Anderson.

"Our testing shows it is unrelated to a H7 strain that was identified in Australia earlier this year, and we believe this case may have happened as part of a spillover event, where laying hens who were foraging outside of the shed were exposed to a low pathogenic virus from wild waterfowl.

"Low pathogenic viruses are present in wild birds here, especially waterfowl like ducks, geese, and swans, and the virus can mutate on interaction with chickens.

"It is important to note that the strain found on this farm is not a wildlife adapted strain like H5N1, so we believe it is unlikely to be transmitted to mammals."

There had been no reports of other ill or dead birds on other poultry farms, and there are no human health or food safety concerns. It is safe to consume thoroughly cooked egg and poultry products.

Mr Anderson says quick action had been taken in co-operation with Mainland Poultry and a restricted place notice issued.

"Test results late last night confirmed the strain, but we already had restrictions in place and expert biosecurity staff on site, with more arriving today. Mainland Poultry took the right steps by reporting ill birds in one shed on the property and locking that building down as testing continued.

"We will move quickly, with Mainland Poultry, to depopulate birds on the remote property, and we’ve placed a 10-kilometre buffer zone around it alongside the restrictions preventing movement of animals, equipment, and feed.

"We aim to stamp this out like we did with infectious bursal viral disease that affected chickens in 2019," Mr Anderson says.

John McKay, chief executive of Mainland Poultry, which manages the free-range farm, says it is committed to taking quick action.

"We have been preparing for an event like this for some time, knowing that low pathogenic avian influenza is already present in New Zealand wild birds. Fortunately, this is not the H5N1 type that has caused concern for wildlife in other parts of the world. International experience with avian influenza has shown us this particular strain (H7N6) can be eradicated quickly and successfully.

"We will be working closely with MPI to depopulate the affected shed, ensure rigorous testing of all other birds on the farm and manage the situation effectively. I’m confident with swift action and collaboration we can eradicate this," says Mr McKay.

Mr Anderson says Biosecurity New Zealand is working closely with industry partners to ensure the find was dealt with quickly and any possible impacts to trade limited.

"Importantly, the farm has strong biosecurity standards and Mainland is helping with ongoing investigation and tracing of animal movements.

"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.

"If anyone sees 3 or more sick or dead wild birds in a group, report it immediately to the exotic pest and disease hotline on 0800 80 99 66 so we can investigate the cause."

For further information and general enquiries, call MPI on 0800 00 83 33 or email info@mpi.govt.nz