Going for a swim in the lake felt great, but as you step out of the water, you find blood dripping from your legs. Leeches!
A parasite that lives to suck blood from unsuspecting victims, the aquatic leech is found throughout North America and is common in the North, especially the Great Lakes region and Canada. Leeches thrive in weedy ponds and lakes, heavily vegetated marshes, muddy ditches, and sluggish streams. Despite their nasty tactics, leeches are actually relatively harmless to humans and don't transmit disease the way certain blood-sucking mosquitoes and ticks do.
Still, leech-country travelers should tuck in their clothes before slogging through wetlands and consider the potential consequences of a posthike dip. When leeches feed, they produce an anticoagulant to prevent clotting and ensure easy bleeding. The bleeding often continues long after the leech has left. You probably won't realize you've been bitten until after the leech has fallen off.
If you find one on you, scrape it away with a fingernail. Treat the wound with a disinfectant or antibiotic cream to ward off infection, and apply pressure to stop the bleeding.