Facts: Tick-borne diseases
Between 10 and 20 percent of all ticks carry Lyme disease. Less than 1 percent of all ticks carry TBE.
Lyme disease:
Lyme disease is caused by a group of bacteria that ticks can carry. The bacteria are found in the tick’s stomach/intestinal tract.
In Sweden, approximately 10,000 people are infected with Lyme disease each year.
You can have Lyme disease without knowing it because the disease does not always cause any symptoms. Lyme disease can heal itself.
TBE:
TBE (tick-borne encephalitis) or tick-borne brain inflammation (encephalitis) is caused by a so-called flavivirus. It can manifest as encephalitis and meningitis with high fever, severe headache, neck stiffness and paralysis symptoms. Deaths are very rare.
The first signs of illness are noticed one to two weeks after being infected. The disease begins with fever.
There is no known cure.
In Sweden, TBE is most common near the Baltic Sea and in areas around Lake Vättern and Vänern. But the disease has spread to the west coast and occurs in large parts of southern and central Sweden.
Sources: Public Health Agency, fästing.nu, NE
Already at the beginning of February, Region Värmland, as the first region this year, went out and recommended that everyone who is going out in the woods and fields get vaccinated against TBE.
But it is unlikely that the ticks, which spread the disease, would already be at work now, according to Kajsa Glemhorn, biologist and tick expert.
“Normally, they go into hibernation during the winter period and start foraging sometime around April when the spring sun comes,” she says.
Wakes up at five degrees
What the season will look like is also hard to say. The local variations are large and winter has not yet released its grip on Sweden.
— Now it’s going to be a cold snap next week. Basically all of Sweden gets colder weather and the ticks can’t handle it, then they go down. They are very temperature dependent.
The ticks need around five degrees in daily average temperature to wake up. Low temperatures without snow are the worst for the ticks, which are otherwise protected by an insulating blanket of snow. However, a short cold snap is rarely a problem, says Glemhorn.
— The big ones go into a resting stage, but they are up again quite quickly. If there is a week of warm weather, they are not late in coming up and foraging again.
Found all year round
In addition to TBE, many ticks also carry Lyme disease, which infects up to 10,000 people in Sweden each year.
Although it is difficult to say how many ticks there will be this year, most indications are a long season – depending on climate change.
Warmer spring and fall days have greatly extended the tick season, and in the lower south you can even find ticks in the winter.
— I’m not surprised to find them all year round, depending on where I am. I have found several pieces in January, but they are single specimens, says Kajsa Glemhorn.