Pictures of dead wild birds' carcasses, people in white suits carrying dead poultry out of barns – these are not new to anyone involved in poultry farming or bird conservation all across Europe.

Poultry farmer Alrik Visscher from Dalfsen in the eastern part of the Netherlands is one of the farmers who has lost all his birds because of the flu. Visscher runs a family farm together with his parents, where four of his barns are now empty. Normally, up to 115,000 chickens would be walking around here, picking grain and laying eggs. Now, the Visschers are cleaning and disinfecting everything.

It was August 1 when Visscher discovered the first signs of the bird flu in some of his birds: They were quieter, blinking, some already dead. Just a day later, all the other chickens were culled as a protective measure.

"It's a mess what you feel: You feel sad, but you also feel: We have to do it like this," Visscher remembers. "Because you have so many chickens, you don't think you have bond with them. But then you're gonna discover that." Not only emotionally, but also financially the farmers are hit badly. They lost all their sources of income. 

Current bird flu season does not end

There have been regular outbreaks of this sickness, which is deadly for many birds, for more than year, though normally, the bird flu season in Europe lasts from October until April or May. Poultry farmers, bird conservationists and the European Food Safety Authority (EFSA) all claim that this epidemic season is exceptional. In the Netherlands alone, more than 4 million chickens and ducks had to be culled, while hundreds of thousands wild birds have died.

Barely any European country escaped cases of bird flu among wild birds or poultry since the beginning of this season in October 2021. What's new is that colony-breeding wild bird populations along the northwestern coasts of Europe are affected, according to the EFSA's latest report.

But also in the US, new outbreaks have been registered every other day. Just like in the Netherlands, where the density of poultry farms is among the highest in Europe. According to the EFSA, high poultry density is one of the factors leading to a faster spread of the virus, which usually comes from Asia via migratory wild birds spending the winter in Europe. When they leave in April, the virus normally leaves with them. Not this year, however: In the Netherlands, waterfowl are the most affected.

'It can come from anywhere'

Gusts of wind carrying the feathers of infected birds, mice who touched bird droppings – It is small things like these that can bring the virus into the barns of poultry farmers. Although the countries have introduced tight hygiene measures, outbreaks have not stopped.

Between October and July, no chickens were allowed to go outside in the whole of the Netherlands, a quarantine that is still in place in huge parts of the country.

A positive test at one farm leads to the installation of a 3-kilometer-wide-protection zone in which all farms have to prove they have no bird flu – and at affected farms all birds are culled as the virus is highly infectious. It kills fast, as Visscher had to find out. On the first day, he found 10 dead chickens, but the next day there were already hundreds of them.

"We have done everything we could so that the virus stays outside our farms," said Bart Jan Oplaat, chairman of the Dutch Union of poultry farmers. The rules in France, the second largest poultry producer in the EU, are very similar.

The outbreaks are also devastating among wild birds, explains Ruud van Beusekom, spokesperson of Vogelbescherming Nederland, an organization of Dutch bird conservationists.

He is especially worried about the population of sandwich terns, a species has been on the red list of endangered species in the Netherlands even before the bird flu outbreaks. As the population was beginning to recover, 25,000 sandwich terns died this year because of the flu.

Quarantine measures also for farmer families

But a solution is not in sight. Measures like quarantines and early cullings of animals on the farms can lower the threat of a spread – but they cannot contain it completely. The Visschers have also had to keep all their animals inside, after a duck farm nearby caught the virus.

The ducks themselves were inside before the outbreak. Some poultry farmers are even reducing their own activities outside of their farms to make sure they don't bring the virus to their animals, according to Oplaat of the Union of Poultry Farmers. Children playing at different houses or farms have to shower right away, when they get home, for example.

Another idea among Dutch farmers: Nets that collect feathers and other particles that could contain the virus from the air. Oplaat reported that two farms with these nets still had an outbreak of bird flu. And it will take some years until a proper vaccine is available. EFSA will soon start to collect data to assess vaccination strategies at least until July 2023 and trials to test bird flu vaccines have already started in France and the Netherlands.

Even if this vaccine is available, bird flu will not vanish. Wild birds cannot be vaccinated and the virus is likely to mutate further. This is also the reason why it stayed this year. In rare cases, mammals also caught the bird flu, but the risk for humans is very low, according to the EFSA. The only hope among bird conservationists and farmers is now: A vast spread of the virus leading to a high immunity among the local birds.

Farmer Visscher is now preparing to host new chickens. Until the end of October, his entire farm will have to be disinfected and cleaned. New hygiene measures are to be announced; only then can new birds arrive. But when the migratory birds from Siberia return for the winter, they may bring new variants, which could change the situation again.

Edited by: Nicole Goebel