Humans have long been discouraged from tolerating the parasitic behavior of the tick. These pathogen-ridden arachnids latch onto their hosts for a blood buffet while transmitting a variety of diseases through their bites. Typically, ticks in infested areas wait for their hosts to stand or pass by and hope a bare leg presents itself.

But not all ticks are so passive. In the Netherlands, there have been reported sightings of Hyalomma marginatum, a kind of Andre the Giant of ticks that are twice the size of a more common species, Ixodes ricinus (sheep tick). Worse, they don’t sit idle. If they want to bite you, they’ll run after you.

The non-native species has been spotted twice in the past month. One was in Drenthe, a province in the northeastern part of the country, and the other was found in Achterhoek. They measure up to 0.2 inches but can grow to 0.7 inches when engorged with the blood of their hosts. The ticks are known to hide in brush. When they spot a potential meal, they run toward it. H. marginatum can detect a victim from up to 30 feet away and track it for 10 minutes before abandoning pursuit.

The species is typically found in northern Africa and Asia as well as parts of southern and eastern Europe. How did they get to the Netherlands? Researchers theorize they hitchhiked on migratory birds. And while their appearances have been scarce, they’re still a cause for concern. H. marginatum is known to harbor the virus that causes Crimean-Congo hemorrhagic fever, which lists uncontrolled bleeding among its undesirable symptoms. The ticks, which were collected for analysis, tested negative for that disease but one was positive for the bacteria Rickettsia aeschlimannii, which causes spotted fever.

There have been no sightings of H. marginatum in the U.S., but native ticks remain a perpetual concern. If you’re outdoors, it’s always a good idea to monitor yourself for ticks and take steps to remove them safely.

[h/t LiveScience]