The Council of State addressed a case on Monday regarding measures taken against tiger mosquitoes. These exotic mosquitoes can transmit serious diseases. That’s why we don’t want them here, but according to experts, we are going to lose the fight against the insect.
“It’s a matter of time, then we’ll lose the fight and then they’ll just be here,” says mosquito expert Bart Knols. Tiger mosquitoes can transmit tropical diseases such as dengue, chikungunya, and zika. There are vaccinations for dengue and chikungunya, but currently, they are only given to travelers.
The most common symptoms in people with dengue are severe headaches behind the eyes, high fever, vomiting, and coughing. With chikungunya, it often involves fever, painful joints, and sometimes a rash.
Besides the diseases they can transmit, what’s annoying about tiger mosquitoes is that they bite during the day. “If a mosquito bites at night, you put up a screen or lie under a mosquito net and then you are protected,” says Knols. That doesn’t work during the day. “Then you go to a terrace to drink a cappuccino and you get caught.”
Tiger mosquitoes are not yet established in the Netherlands. The Netherlands Food and Consumer Product Safety Authority (NVWA) is the agency that tries to stop the mosquitoes. “To date, the NVWA has always managed to get local outbreaks under control,” says Knols. The first tiger mosquito was discovered in 2005. After that, the numbers increased.
“2023 was really a peak year,” says mosquito researcher Tessa Visser from Wageningen University & Research. Then 150 reports were made. In 2024, there were 106 finds. This year, there have been 25 observations so far.
“If you look at the broader picture within Europe, the situation becomes a bit more anxious,” says Visser. In the countries around us, the tiger mosquito has already established itself. For example, the map below shows that there are tiger mosquitoes just across the border in Belgium and Germany. “We are, as it were, being enclosed from the south.”
Vacationers bring mosquitoes with them
“Originally it was a problem of tire importers and importers of bamboo plants,” says Knols. But now the problem is much broader. “It’s really about the Dutch public taking the mosquitoes with them,” adds Visser. The tiger mosquitoes hitch a ride with people returning from vacation from countries where the insects have already established themselves, such as France, Spain, and Italy.
“Those mosquitoes lay eggs in someone’s garden and then we have an outbreak in the middle of a residential area,” says Knols. “The European Union addressed this whole problem far too late. And these animals don’t stop at the border.”
Therefore, there comes a moment when fighting is no longer useful. Visser estimates that it will be within three to five years. “But the fact that we have that mosquito here does not necessarily mean that we also have the viruses that such a mosquito can transmit.”
In addition to a mosquito, there must also be people who have the disease to transmit viruses, and the two must come together “in a longer warm period,” Visser emphasizes. “The temperature is important for the mosquito, but also for the virus.”