Lyme disease is a bacterial infection transmitted by ticks that affects humans and animals. Not always, but often, sometime after the tick bite, a rash may appear. The rash usually appears at the tick bite location but can appear anywhere on the body. The rash can vary in appearance, but sometimes looks like a "bulls-eye". Early in the disease the rash is often accompanied by flu like symptoms. The later phases of the disease can bring on arthritis, headaches, and other systemic problems including various neurological manifestations. The heart, brain, eyes, ears, and other parts of the nervous system may be affected. Blood testing is sometimes unreliable and treatment with antibiotics is necessary for cure after a clinical diagnosis.