Ticks are small, insect-like creatures that can attach to you as you brush past bushes, plants, and grass. Once on you, ticks often move to a warm, moist location, like the armpits, groin, and hair. At that point they typically attach firmly to your skin and begin to draw blood.
Ticks can be fairly large -- about the size of a pencil eraser -- or so small that they are almost impossible to see. Ticks can cause a variety of health conditions ranging from harmless to serious.
This article describes the effects of a tick bite.
See also: Tick removal
Hard- and soft-bodied female ticks are believed to make a poison that can cause tick paralysis in children.
While most ticks do not carry diseases, some ticks can carry bacteria that can cause:
Ticks live in wooded or grassy fields.
Holm AL. Arachnids, insects, and other arthropods. In: Long SS, Pickering LK, Prober CG, eds. Principles and Practice of Pediatric Infectious Diseases. 2nd ed. Philadelphia, Pa: Churchill Livingstone; 2003:chap 299.