Lyme disease is a bacterial infection, caused by the spirochete Borrelia burgdorferi and acquired through tick bites. Lyme disease is the most common tickborne disease in the United States. It also frequently occurs in Canada, Europe, and Asia.  It starts as a small bump from the bite and may turn into a rash after a few days or weeks. If not treated early, it may spread to other parts of the body.

Causes

A recently discovered germ named Borrelia burgdorferi is the cause. It is spread only by tick bites, and cannot be passed from one person to another. The ticks that spread Lyme disease usually live on deer, rabbits, and mice, but also can be found on dogs. Infections are most frequent in the late spring and summer.

Symptoms

Human Lyme borreliosis generally occurs in stages, with remissions and exacerbations and different symptoms at each stage. 
Lyme disease starts with flulike symptoms and a circular rash at the site of the tick bite. A red, circular rash develops anywhere from 1 to 30 days after the tick bite.While redness, pain, and swelling may develop within hours at the site of any insect bite or sting, erythema migrans will appear around the bite as an expanding red, painless area with a central clearing.
Flu-like symptoms, such as headaches, stiff neck, muscle aches and fatigue may also be present. About half of all infected people never develop the rash, making it more difficult to diagnose the illness.
If left untreated, Lyme disease can progress to a second stage of the disease, which occurs within the next several weeks. This disseminated infection involves joint pain and may bring about complications in the nervous system or the heart.

Treatment

The doctor may need to order blood tests to make sure you have the disease. Antibiotics are prescribed to cure the infection. Medicine for pain, irritation, and swelling may be given, if needed. Early treatment is important.

The sooner you are treated, the better your chances of full recovery. Lyme arthritis can be treated successfully in most patients by a number of alternative antibiotics including tetracycline, doxycycline, erythromycin or amoxicillin. Response, however, is often delayed until many weeks after completion of the course, which suggests that noninfectious inflammatory mechanisms can contribute to the perpetuation of arthritis in many patients.
Lyme disease patients with neurological symptoms are usually treated with the antibiotic ceftriaxone, which is given intravenously once a day for a month or less.
Lyme disease patients experiencing heart symptoms are treated with antibiotics, such as ceftriaxone or penicillin, given intravenously for about two weeks.