They nest outdoors under stones, boards, bark and other moist protected places. Bites from the large centipede are rare. The pain associated with the bite from S. viridis can be intense, lasting for several hours. Leeches are members of a group of segmented worms that live in fresh waterponds, marshes, lakes and streams. A fresh water leech feeding between toes.
Leeches prefer shallow water and waders are more likely to become infested than swimmers.
One rare undocumented encounter with leeches occurred in central Georgia in 1993. A young man was walking across a recently drained lake bed and became infested with many black inchworm looking creatures. Leeches are not a medical concern but people working or recreating outdoors may happen onto a few of the bloodsuckers occasionally.