7 May 2024

The mutant bird flu lurking on our borders

From The Detail, 5:00 am on 7 May 2024

Avian flu is mutating and adapting to spread beyond poultry farms to wildlife and mammals, including humans. It's not here yet, but it's coming closer

Staff vaccinating an animal against bird flu at Guangzhou Zoo in Guangzhou, south China in late 2023.

Staff vaccinating an animal against bird flu at Guangzhou Zoo in Guangzhou, south China, 7 November, 2023. Photo: AFP/ Ma Xiaocheng

Highly pathogenic avian influenza - H5N1, or bird flu - has been flying around the world since the late 1990s. 

New Zealand, Australia and the Pacific Islands are so far free of it, but now it has been discovered in mainland Antarctica and scientists say it is only a matter of time before it gets here. 

By then, it will be more than just a virus that hits ducks and poultry farms, although that is bad enough. 

The virus is mutating and has transferred with devastating effects into wild bird populations. 

It has also turned up in mammals. 

Cows, ferrets, minks, sea lions, cats on dairy farms, bears  - and humans.

There is no certainty on what the virus will do now, or how severe a human epidemic could be, but those alarm bells have started ringing. 

"H5N1 right now looks like the thing that we're most aware of that could potentially become a pandemic or an epidemic among humans," says Newsroom's Marc Daalder. He wrote about this over a year ago and while it has not come to fruition as the next Covid-19 style disaster yet, we seem to be moving closer to it. 

"We can't say for sure this is it, but it's something that we can see happening and there are several reasons to be quite worried about it, and potentially quite a bit more worried about it than we were five years ago." 

He talks to The Detail today about the development of the virus through its mutations to the stage where it has been found in 33 herds of cattle in nine states of the US, with some milk testing positive for remnants of it. Two people closely associated with farms have also caught it, but their cases are mild. 

However people have died in previous outbreaks where the virus was caught directly from chickens, rather than from other people. In a severe outbreak in Hong Kong in 1997, six people died of the 18 confirmed with H5N1. This was the first outbreak in humans. There have been others since, and the overall fatality rate has been about 50 percent.  

It is possible that in order for the virus to adapt to human transmission, it has become less dangerous to us. But we do not know for sure, and it is enough to spark concern from scientists. 

Our government has an action plan for when or if H5N1 hits our shores, with the Ministry for Primary Industries, Health Ministry, the Department of Conservation and biosecurity authorities all working together. 

MPI chief veterinary officer Dr Mary van Andel tells The Detail they will be asking the public to watch out for dead birds (don't touch them) and to ring into the exotic pest and disease hotline which is 0800 80 99 66. 

"We'll be asking people to keep an eye out for clinical signs in other animals, report those to their veterinarians, report those to the hotline. We'll be asking people to listen to public messaging, and do those things so that we can get the best path through this for New Zealand." 

She says DoC is trying out vaccines on captive bird populations, but it is a tricky job - first you have to catch them, they need two doses a month apart, and the immunity doesn't last forever. 

Authorities here are also in contact with colleagues in other countries that have been hit with mass-bird deaths, to get an understanding of the challenges of dealing with H5N1 and find out what needs to be in place to deal with an outbreak.  

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