Welcome to your worst nightmare. You’ve lost your balance and fell into a pool of slimy parasitic animals that eat only one thing. Your blood. What would happen if you were at the bottom of this pool ...

The first time I was bitten by a leech, I was swimming in a West Virginia river. I remember the scene perfectly: I crawled out to dry off and tried to wipe the mud off my knees, but the leech wouldn’t ...

As we tidy away the Dracula capes and glow-in-the-dark plastic fangs for another winter, one notorious blood sucker has had a particularly good year. For the first time the medicinal leech Hirudo ...