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.
Source: European farmers struggle to contain deadly bird flu | Science | In-depth reporting on science and technology | DW | 03.10.2022