2023-05-06 05:00:05
The number of people contracting Lyme disease after a tick bite has risen sharply in recent decades. Climate change seems to be playing a role, although it is difficult for scientists to figure out exactly how.
Every year, the Dutch are affected by a tick bite about one and a half million times. Most people do not suffer from this, but 27,000 people are affected by Lyme disease every year. More than a thousand people have long-term complaints about it. Twenty years ago, the disease was four times less common.
It is quite possible that the rising temperatures will cause the tick to advance, says biologist Arnold van Vliet of Wageningen University & Research. He has been researching the spread of the tick for many years, including through Tekenradar.nl. There, people can report tick bites themselves, to map out where and when ticks most often strike.
Ticks are active when the minimum temperature is just above freezing. Due to climate change, this is more often the case and there are therefore more times when ticks are active. They can then look for a ‘host’ to suck blood from. That can be a human, but also a deer or a mouse.
Those mice have a better chance of surviving the winter due to the higher temperatures. As a result, they are more often available as hosts, says Van Vliet. Moreover, more food may be available for the mouse. “The warmer summer affects the production of acorns and beechnuts. This seems to be increasing due to the higher temperatures. That has positive effects on mice, and that can have an effect on ticks.”
Ontvang meldingen bij nieuws
More often in green
The number of ticks living in Dutch green areas seems to be increasing due to all these factors. But it is not exactly clear to what extent the growth in the number of Lyme patients is related to this.
Our own behavior may also play a role, says Van Vliet. Due to the warmer weather, we are more often looking for nature and we may also wear shorts or a T-shirt more often. “This makes it easier for the tick to end up on the body.” And so the number of tick bites is increasing.
Increasing drought can actually cause ticks to have a harder time. During prolonged drought, ticks have to hide in the litter layer on the forest floor. As a result, their chances of survival may shrink again.
Giant tick is moving north
In the future, climate change may have an effect on the arrival of other tick species, in addition to the sheep tick, which is now the most common. In recent years, for example, the hyalomma tick has been found a small number of times in the Netherlands and Germany. This ‘giant tick’ can be brought by migratory birds from the south.
The hyalomma tick can transmit the serious Crimean Congo virus. If temperatures continue to rise, this tick could establish itself in parts of the Netherlands by 2080, calculated scientists ten years ago.
“It is not yet the case that this will be a problem in the Netherlands, but it is something to keep an eye on,” says Van Vliet. “Also in Southern Europe, where we go on holiday a lot.”
Count structural sign
It would be good to start counting structural ticks again in various places in the Netherlands, says Van Vliet. From 2006 to 2016 he did this with a group of volunteers, but there is no money left for it now.
“The climate has an effect on ticks in all kinds of ways. With further climate change and greening of the country, you have to take the tick problem into account,” concludes the biologist. “But it is very complex and therefore not easy to solve. Especially now that we have no structural monitoring of the tick.”
In het groen geweest? Doe een tekencheck
- Wie in het groen is geweest, doet er goed aan altijd even een tekencheck te doen. Dat is de belangrijkste manier om besmetting met de ziekte van Lyme en andere tekenziektes te voorkomen.
- Vind je een teek? Zet een pincet met een scherpe punt dicht op de huid en trek hem recht omhoog eruit.
- Hoe langer een teek vastgezogen zit, hoe groter de kans op ziektes. Het is dus goed om de tekencheck direct na een bezoek aan de natuur te doen.
- Bang zijn voor de teek hoeft niet, zegt Van Vliet. “Gewoon lekker blijven genieten van het groen, dat is heel belangrijk en gezond. Maar blijf wel alert op teken.”
Improvement: This article previously stated that mice are hibernating for less time due to the higher temperatures. That’s not right: mice don’t hibernate. However, they are more likely to survive the winter at higher temperatures. This has been corrected in the article.
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