As if the coronavirus wasn’t enough. For the first time, the West Nile virus has surfaced in the Netherlands, to be precise: in a warbler in the Utrecht region. Because this is not a migratory bird, the animal probably contracted the virus in the Netherlands itself.
The virus can also infect humans. In about 1 in 5 this leads to flu-like symptoms. In rare cases neurological problems arise, which can even lead to death. Infamous is the virus for the theory that the germ would have killed Alexander the Great in 323 BC.
“This is not unexpected. We have been prepared for this for a long time now, ‘says virologist Chantal Reusken (RIVM). After all, the virus has been on the rise in Europe for decades. Since 2018, it appears to have settled in Germany, where it has even been found in the northern port city of Hamburg.
The spread is via mosquitoes, which contract the virus when they feed on infected birds. The mosquitoes can then infect other birds, but also horses and humans, for example. “People accidentally get infected. This is a bird virus, ‘says Reusken.
Antibodies against virus
Incidentally, the question is whether the virus has really established itself in our country, emphasizes the RIVM expert. After all, it is also conceivable that the virus will not survive the winter and will die out again. Antibodies against the virus have already been found in coots.
A whole series of factors are needed before the virus can reproduce in our regions, Reusken explains. The warmer climate can contribute: the body temperature of mosquitoes then becomes warmer, so that the virus can multiply better and mosquitoes secrete virus more quickly.
“I don’t really like to keep up with the climate everywhere,” says Reusken. “But in this case, climate change is really one of the factors that comes into play.”
Accidental discovery
The infected warbler was found by One Health Pact, a consortium of researchers coordinated by Erasmus MC. The aim of the consortium is to detect the arrival of exotic viruses as quickly as possible.
An accidental discovery, Reusken emphasizes. “I myself would have put my money on a dead bird of prey in the zoo, after which an autopsy shows that the virus is at play. Those are usually the places where you find this virus for the first time. “
