Migrating birds could bring lethal avian flu to Australia’s vulnerable birds

In 2021, bird flu evolved into a new form – a new and remarkably deadly strain found for the first time in Europe.

Bird flu is usually most dangerous for birds kept in confined spaces, such as chicken farms. But as it spread around the world, the highly pathogenic HPAI A(H5N1) variant also began killing millions and millions of wild birds.

Seabird colonies in the UK have been decimated. The virus can kill up to half of the birds it infects. It has also spread to sea lions and seals.

Fortunately, it does not spread easily in humans. Have more than 50 million birds already cleared more than 37 countries to slow the spread.

The Australian birds have so far evaded this bullet. Our isolation has kept us safe for now. The birds of Antarctica have also remained safe. But if this variant ends up here in the lungs of a migratory shorebird, our unique birds are at great risk. For example, black swans are particularly vulnerable to all types of bird flu.

The federal government will stimulate surveillance measures when large flocks of migratory birds arrive later this year. It is unlikely that this will be enough as we enter a time of great risk from September.

Could it really come here?

Yes.

Surveillance of Australia’s vast coastlines is next to impossible. Instead, the government is likely to focus on the large wetlands and shallow inlets that attract migratory birds.

Every year, about eight million birds catch the East Asian-Australian Flyway – a route stretching from the Arctic Circle through East and Southeast Asia to Australia and New Zealand.

Is the H5N1 Flu Deadly Enough to Limit Itself? Not necessary. A bird can receive a mild dose and still be contagious when it arrives. That means there is a good chance that this variant will arrive. It would only take one contagious shorebird to cause outbreaks.

If it gets here, the virus will decimate poultry farms and wild birds, just as it did abroad. In densely populated farms, it can kill 90-100% of all birds.

It could pose an extinction threat to iconic birds like black swans, which have an immune deficiency that puts them at particular risk. Flocking birds such as rainbow lorikeets and corellas would also be at additional risk of contracting the virus.

Federal Agriculture Minister Murray Watt has dismissed the idea that Australia is unprepared.

He said his administration had been “closely monitoring the global HPAI situation” and stepped up early warning efforts.

But what we don’t have is an action plan for what happens if the virus does arrive, as it seems likely.

Responses such as the massive destruction of beehives after the devastating varroa mite arrived are unlikely to work for a virus. A tailor-made vaccine could help domestic birds, but it would be virtually impossible to administer to wild birds.

Over time, birds with a natural resistance would survive and rekindle populations. But endangered species or particularly vulnerable species would find it much harder to bounce back.

Read more: Australia’s iconic black swans have a worrying immune system deficiency, new genome studies find

Have our birds not survived bird flu before?

Yes, but not quite like this one.

Three egg producers in Victoria in 2020 had an outbreak of another highly pathogenic flu strain, H7N7. To prevent the spread, the authorities have culled all birds on the farms.

This variant arose when low-pathogenic viruses carried by local wild birds evolved into a more lethal form. Although authorities stopped its spread on poultry farms, there was nothing they could do about the wild reservoir of the virus.

If H7N7 is still around, it could spell even more trouble. When two different influenza virus subtypes infect the same host cell, their genetic material can mix to create a new virus, which can be milder or more severe.

Australian scientists have investigated the impact of low pathogenic bird flu on many bird families, providing some insight into how highly pathogenic bird flu may spread in Australia. For example, dry areas would probably be better protected against the virus, which does not like dry conditions.

But can we act in time? We know what to do if there is an outbreak in domestic birds. But if the virus gets into wild birds and takes off, we have no plan.

Rapid monitoring and surveillance of pathogens in the wild is a major gap in Australia’s biosecurity framework – and one we need to fill.

We must prepare

COVID from bats or raccoon dogs. Ebola of bats. Bird flu by birds. If we push nature into a corner, we may find ourselves more exposed to the viruses that wild animals carry.

So far, only the HPAI H5N1 strain is known to have jumped into humans handful of times.

That’s lucky. Since 2003, about 800 people have contracted one of the variants of bird flu. More than half of these have died. That’s a mortality rate similar to many of the birds dying from bird flu elsewhere in the world. The most important protection we currently have is the fact that bird flu finds it difficult to infect us in the first place.

To save our birds – and possibly ourselves – we need a better way to detect and track viral outbreaks in wildlife, especially those that can spread to humans.

Read more: What is spillover? The bird flu outbreak underscores the need for early detection to prevent the next major pandemic