1. Lyme disease is a bacterial illness caused by a bacterium called a "spirochete."
  2. Lyme disease affects different areas of the body in varying degrees as it progresses. The site where the tick bites the body is where the bacteria enter through the skin. Initially, the disease affects the skin causing an expanding reddish rash often associated with "flu-like" symptoms. Later, it can produce abnormalities in the joints, heart and nervous system.