H5N1: ‘Game-changer’ for northland poultry and egg producers

Free range egg farming in Northland - the industry is looking into the risks from avian flu. Photo / Adrian Malloch

Northland’s poultry and egg producers are bracing themselves for the possible arrival of a highly infectious strain of avian flu but will at least have slightly longer to prepare for it than producers elsewhere around the country.

New Zealand previously enjoyed a world unique status of being free from the three big poultry diseases - virulent Newcastle disease, infectious bursal disease, and highly pathogenic avian influenza (HPAI). It’s the reason for our blossoming and lucrative chicken meat trade to Asia.

However, the discovery of the HPAI strain H5N1 in Antarctica’s wild bird population at the end of last year was a “game-changer”, the executive director of both New Zealand’s Egg Producers Federation and the Poultry Industry Association Michael Brooks said.

Overseas, the disease has killed millions of birds since 2020 and spread to about 23 countries.

With a real risk of an outbreak now on New Zealand’s horizon, Ministry for Primary Industries (MPI) representatives and leading industry officials were working hard to prepare for the possibility, focusing on such issues as decontamination and the disposal of dead birds.

Study groups from the stakeholder entities were about to embark on two week-long trips to Australia and Europe to look at farms there, talk to regulators, and to learn more about the disease, Brooks said.

South Korean soldiers national veterinary and quarantine service pictured burying ducks at a farm affected by a highly pathogenic avian influenza in Cheonan, southeast of Seoul on December 22, 2003. Photo / Getty Images

Twelve of the country’s 146 commercial-scaled egg or poultry producers were in Northland and with the risk now coming from the south, would at least have slightly longer to prepare for any outbreak, Brooks said.

For Northland, ironically, in the past the risk of avian influenza would’ve been from birds from the Northern Hemisphere, but we’ve never found it (the disease),” he said.

The migratory birds from the north tended to be waders, which didn’t seem to get avian influenza. It was also thought that if they did get it, the birds would succumb to the disease before they got here. It kills within 24 to 48 hours.

Birds such as Bar-tailed godwits migrate to New Zealand for the summer but have never been implicated in any risk of avian flu here. Photo / NZME

While Australia had battled outbreaks of HPAI, it hadn’t yet had H5N1 of the type we needed to fear. The flurry of strains recently there didn’t get into wild birds so there was no concern about migratory birds from Australia bringing it across to New Zealand.

However, the H5N1 strain, now endemic in wild birds in Antarctica, posed a different risk. Although in the part of the continent closest to South America - so still thousands of kilometres away from New Zealand - there was a potential risk that a bird such as a Skua Gull could eat a dead sea lion that had caught avian influenza and could then fly here with the disease, Brooks said.

H5N1 transferred to some mammals as it had done in the US where dairy cows had been infected. While cattle hadn’t died from the disease, sea lions in Antarctica had, Brooks said.

Scientists have been growing increasingly concerned by the spread and evolution of H5N1 avian flu, which has been detected in two dozen countries and killed tens of millions of poultry birds. Photo / 123RF

Free range farming operations were particularly at risk. Birds roaming outside, sharing outdoor water sources were prone. While in the past the disease might have been on trucks or on people, it was now on wild birds and if you’re a free range farmer how do you stop wild birds?

In places like the UK, free range farmers were allowed to keep their birds in sheds for three or four months during the highest risk times, without jeopardy to their free range status, Brookes said.

Counterproductive to the Australian problem was the pressure that had previously been put on chicken farmers by Government to create dams on their land to ensure there was water during dry spells. However, that had encouraged ducks, which had brought avian influenza. By contrast, anything that lured wild birds was something New Zealand’s industry had always strongly discouraged, Brooks said. Studies have shown mallard ducks would also be a key carrier of the disease here.

Brooks confirmed there was no risk to humans from eating cooked birds with avian flu. The disease was brutal, symptoms were obvious, and birds succumbed quickly so it was unlikely any infected birds would make it to slaughter. And, the virus would be killed by cooking anyway, Brooks said.

Meanwhile, Biosecurity New Zealand and the Department of Conservation (DoC) were also undertaking preparedness work, including detection surveillance and monitoring around New Zealand and in the sub-Antarctic area.

According to DoC’s website, a vaccine trial was under way to protect the country’s most endangered native birds. As it wasn’t possible to vaccinate all our endangered birds, a focus was on threatened species that were reliant on captive breeding or intensive management for species survival.

A safety and efficacy trial was being carried out on small numbers of five native bird species including kakī (black stilt), takahē, kākāpō, tūturuatu (shore plover) and the red-crowned kākāriki (as a surrogate species for kākāriki karaka/orange-fronted kākāriki).

Trials are under way to see if some of our most endangered native birds can be vaccinated against highly pathogenic strains of avian bird flu before it gets to New Zealand. Pictured here are a nest of red-crested Kakariki chicks, which hatched this year on a predator-free property near Whangārei. Photo / Supplied

MPI approved the vaccine trial, which was being conducted by DoC veterinarians under strictly controlled conditions. The vaccine being used contained inactivated (dead) virus, meaning it couldn’t cause infections with avian influenza.

The MPI said it had strong systems in place to ensure early detection if HPAI did arrive.

“The likelihood of the introduction of HPAI H5N1 through human introduction on pathways that we manage is low. As information emerges about the distribution of the disease in Antarctica, there will be a better understanding about the likelihood of it reaching New Zealand through wild bird movements.”

Sarah Curtis is a news reporter for the Northern Advocate, focusing on a wide range of issues. She has nearly 20 years’ experience in journalism, much of which she spent court reporting. She is passionate about covering stories that make a difference.