Lyme disease is seldom, if ever, fatal, according to the Michigan Center for Disease Control and Prevention. The tick-borne disease, left untreated, can cause arthritis, joint pain and neurologic abbnormalities such as facial palsy or nerve swelling. It occasionally causes heart enlargement or inflammation of tissues around the heart.
Death certificates in the United States from 1999 to 2003 showed 114 with Lyme shown as an underlying or multiple cause of death, according to a study published in the Oxford Journals. Of these 114, the researchers determined that only one was consistent with the clinical symptoms of Lyme. During the same time period, there were 96,068 cases of Lyme reported to the Center for Disease Control, indicating a low mortality rate for the disease.