What is Lyme disease?

Leopold D. Galland, MD
Internal Medicine
Here are some essential facts about Lyme disease:
  • It is an infection with a bacterium called Borrelia burgdorferi, transmitted by the bite of a deer tick.
  • The tick is so small, sometimes as small as a poppy seed, that you may not be aware of a tick bite.
  • Symptoms of Lyme disease may occur within days or may not occur for many weeks after infection.
  • Lyme disease may involve any part of your body: skin, joints, muscles, the nervous system, the heart, the intestinal tract.
  • Laboratory tests for Lyme disease are imperfect and can be misleading.
  • Prompt treatment of early infection improves the likelihood of cure, but persistent chronic infection may occur and can take many forms.
  • The possibility of Lyme disease should be carefully considered in anyone with unexplained fatigue, fever or muscle pain, in people with an acute unexplained change in emotional or cognitive function, and in everyone given a diagnosis of autoimmune or degenerative neurological disease.

Lyme disease is the result of infection with the spirochete Borrelia Burgdorferi. It is generally thought that the infection is the result of a tick bite, which about 50% of the time results in a rash, often described as a ‘bulls eye’ rash, but which can vary in appearance.

Symptoms of untreated Lyme disease typically include joint aches which seem to migrate from one joint to another over days), flu-like symptoms (fever, chills, body aches, headache), neuro-psychiatric problems (e.g., Bell’s palsy-paralysis of one side of the face; numbness, weakness, mood disorders, psychosis, cognitive impairment, even seizures). Some people report abnormal heartbeats (conduction abnormalities), or gastrointestinal problems.

There is an extreme polarization around the twin questions of diagnosis and treatment for those with Lyme disease. The highly charged and politicized conflict between the Infectious Disease Society of America (IDSA) and International Lyme and Associated Diseases Society (ILADS) is well described in Pamela Weintraub’s excellent book, Cure Unknown.


Lyme disease is a bacterial illness caused by a bacterium called a "spirochete" that is transmitted to humans from the bite of a deer tick. It can cause abnormalities in the skin, joints, heart and nervous system.

This answer is based on source information from the U.S. Department of Health and Human Services.

Lyme disease is a bacterial infection that you get from a deer tick bite. Deer ticks carry the bacterium Borrelia burgdorferi, which can spread to humans and animals. Lyme disease is typically recognized by the red bull's-eye rash that appears between 3 and 30 days after the tick bite. The disease is treated with antibiotics, and can have serious effects if not treated.

Picture of lyme disease

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.