“It has not turned out to be the tough winter that was predicted,” says a spokesperson for Wageningen Bioveterinary Research.
In January and December, a total of two poultry houses had to be evacuated. In November there were five. But in October and September there were still sixteen and seventeen.
The numbers are much smaller than expected at the end of the summer. Bird flu normally comes with migratory birds in the fall and disappears again in the spring and summer. But last year things went differently and many bird flu cases continued to be added in the summer.
“The forecast for the winter is not good,” said Nancy Beers in september. The avian flu expert from Wageningen University & Research (WUR) was very concerned about the following months.
Thijs Kuiken, virologist at Erasmus MC, also had these concerns. In recent years there has always been a bird species that has been seriously affected by bird flu. Tufted ducks, widgeons (a species of duck), barnacle geese and seabirds have been hit hard in recent years. “The worst-case scenario would be that a new species would be added this winter. Fortunately, that did not happen.”
No explanation for less bird flu
Kuik cannot explain why the number of bird flu cases is smaller than had been taken into account. “That’s speculation. We don’t have enough information from wild birds.”
Francisca Velkers, epidemiologist and poultry veterinarian, is also in the dark. This is also because not everything is clear about wild birds. Although fewer wild birds seem to be infected than during severe bird flu waves.
Not all birds die from bird flu. So it could be that a group of birds is immune, she says. But birds that are immune can still carry the virus and infect poultry in stables.
“We don’t know,” she says. “We haven’t had a situation before where infections have continued all summer. So the whole dynamics of infections in wild birds is unpredictable for us.”
Vogelgriepepidemie was vorig jaar erger dan ooit
- De vogelgriepepidemie was vorig jaar in Europa groter dan ooit. Tientallen miljoenen vogels werden geruimd.
- Wilde vogels kunnen doodgaan als ze vogelgriep krijgen. Als in een stal een besmette kip rondloopt, moet de hele stal worden geruimd.
- Heel soms kunnen ook mensen vogelgriep krijgen. Dat leidt dan vaak tot milde klachten, maar de gevolgen kunnen ook ernstig zijn.
- Als mensen (of zoogdieren) vaak vogelgriep krijgen, kan het virus muteren en mogelijk wel ernstige gevolgen voor mensen hebben.
Bird flu has not completely disappeared
Incidentally, it is not the case that there have been no bird flu cases at all this winter. A number of stables have therefore been cleared in recent months. Wild birds that have died of bird flu are also regularly found. This is also the case in countries around us.
“Vigilance is therefore still required,” says the spokesperson for Wageningen Bioveterinary Research. “The fact that the virus does not behave as we might expect shows how elusive and unpredictable a virus can behave.”
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