Ticks, better known as fästingar in Swedish, can cause Lyme disease and TBE - tick borne encephalitis - a viral infectious disease involving the central nervous system.
And with Swedish summer on the cards (at least according to the calendar), doctors already have their hands full treating patients who have fallen victim to TBE.
Over 20 cases have been reported in Stockholm and Uppsala alone - more than twice as many as at the same time last year, reported the Dagens Nyheter newspaper on Wednesday.
"We're not going out with a warning yet, but this could change as summer progresses," Anders Wallensten, epidemiologist at the Public Health Agency of Sweden (Folkhälsomyndigheten) told DN.
Last year actually saw a drop in TBE in Sweden, from 287 people in 2012 to 209 people, but this year looks set to reverse the trend. In the Uppslaa county alone this season, there have been seven cases of TBE compared to none at all at the same time last year.
Stockholm, meanwhile, has seen 16 cases this year compared to just nine at the same time last year.
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While experts remain unsure why the ticks are more active than usual, they speculated that it may have something to do with a mild winter.
Experts suggested those likely to be spending a lot of time outdoors should get vaccinated. If you're unlucky enough to find a tick on your skin, it's recommended to remove it as soon as possible, with TBE leaving patients with flu-like symptoms and pain in their body.