Lyme Disease

Lyme Disease Slideshow

Medical Author: William C. Shiel Jr., MD, FACP, FACR
Medical Editor: Melissa Conrad Stöppler, MD

• What is Lyme disease? What causes Lyme disease?
• What is the history of Lyme disease?
• What are symptoms and signs of Lyme disease?
• How is Lyme disease diagnosed?
• What is the treatment for Lyme disease?
• How can Lyme disease be prevented? Is there a vaccine?
• Lyme Disease At A Glance
• Lyme Disease - Slideshow
• Patient Discussions: Lyme Disease - How Was Diagnosis Established

What is Lyme disease? What causes Lyme disease?

Lyme disease is a bacterial illness caused by a bacterium called a "spirochete." In the United States, the actual name of the bacterium is Borrelia burgdorferi. In Europe, another bacterium, Borrelia afzelii, also causes Lyme disease. Certain ticks found on deer harbor the bacterium in their stomachs. Lyme disease is spread by these ticks when they bite the skin, which permits the bacterium to infect the body. Lyme disease is not contagious from an affected person to someone else. Lyme disease can cause abnormalities in the skin, joints, heart, and nervous system.

What is the history of Lyme disease?

Interestingly, the disease only became apparent in 1975 when mothers of a group of children who lived near each other in Lyme, Connecticut, made researchers aware that their children had all been diagnosed with rheumatoid arthritis. This unusual grouping of illness that appeared "rheumatoid" eventually led researchers to the identification of the bacterial cause of the children's condition, what was then called "Lyme disease" in 1982.

Ticks are carriers of the Lyme bacterium in their stomachs. The ticks then are vectors that can transmit the bacterium to humans with a tick bite. The number of cases of the disease in an area depends on the number of ticks present and how often the ticks are infected with the bacteria. In certain areas of New York, where Lyme disease is common, over half of the ticks are infected. Lyme disease has been reported most often in the northeastern United States, but it has been reported in all 50 states, as well as China, Europe, Japan, Australia, and parts of the former Soviet Union. In the United States, it is primarily contracted in the Northeast from the state of Maine to Maryland, in the Midwest in Minnesota and Wisconsin, and in the West in Oregon and Northern California.

Picture of a deer tick

Lyme Disease - How Was Diagnosis Established

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How was the diagnosis of your lyme disease established?

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