Lyme Disease

Lyme disease is an infection caused by the bacterium Borrelia burgdorferi that is transmitted by a tick bite. The disease can be difficult to diagnose. It often starts with a large red rash at the site of the tick bite, followed by flu-like symptoms and fatigue. Early in the course of the disease, the symptoms often may go unnoticed or be mistaken for the flu, and not all persons develop the same symptoms. To further complicate matters, the symptoms of the disease mimic those of other diseases, so even persons who complain of flu-like symptoms and fatigue can have any number of conditions other than Lyme disease.

There are blood tests to check for antibodies to the bacterium that causes Lyme disease. The tests, however, are not useful if done soon after a tick bite, because it takes 2 to 5 weeks after being bitten by an infected tick for antibodies to develop. Even when an antibody (blood) test is done later, the result alone does not reliably predict the presence or absence of Lyme disease. (See "How is Lyme disease diagnosed?" below.)

The Food and Drug Administration (FDA), which regulates diagnostic tests for Lyme disease, has cleared for commercial sale and distribution only blood tests for antibodies that may be present in Lyme disease. Tests for Lyme disease that use urine or other body fluids have not been cleared by FDA.

Lyme disease is so named because it is generally believed to have first been observed in and around Old Lyme and Lyme, Connecticut in 1975. Before 1975, elements of Borrelia infection were also known as "tick-borne meningopolyneuritis", Garin-Bujadoux syndrome, Bannwarth syndrome or sheep tick fever.