Lyme disease is a bacterial infection resulting from the bite of an infected tick. The most common type of tick that carries the bacteria is the tiny deer tick, or black–legged tick, which is about the size of a poppy seed. Another tick thought to spread the disease is the lone star tick.

A tick picks up the Lyme disease bacteria, called Borrelia burgdorferi (B. burgdorferi), when it bites an animal that is infected with it.

When an infected tick attaches to you and maintains contact with your blood, the bacteria can travel from the tick’s gut to your bloodstream. Once the bacteria enter the bloodstream, they can move to different parts of the body. Common sites of infec