Return to Index
Conditions InDepth: Lyme Disease
Lyme disease is a bacterial infection resulting from the bite of an infected tick. The most common type of tick that carries the bacteria is the tiny deer tick, or black–legged tick, which is about the size of a poppy seed. Another tick thought to spread the disease is the lone star tick.
A tick picks up the Lyme disease bacteria, called Borrelia burgdorferi (B. burgdorferi) , when it bites an animal that is infected with it.
When an infected tick attaches to you and maintains contact with your blood, the bacteria can travel from the tick’s gut to your bloodstream. Once the bacteria enter the bloodstream, they can move to different parts of the body. Common sites of infection include the skin, joints, muscles, nerve tissue, and distant skin sites. Ticks are most likely to transfer the infection to you after being in contact with your blood for 2 or more days. If the bacteria is transferred the symptoms usually begin to develop in about 1 week.
According to the Centers for Disease Control and Prevention in the United States, the number of Lyme disease cases per year ranged from 19,804 to 29,959 from 2002 to 2011. The disease is concentrated in certain parts of the country where both the ticks that carry the Lyme bacteria and the mice, deer, and chipmunks that the ticks live on are common. Although Lyme disease is most frequently associated with the northeast United States, it has been reported in nearly all states.What are the risk factors for Lyme disease?What are the symptoms of Lyme disease?How is Lyme disease diagnosed?What are the treatments for Lyme disease?Are there screening tests for Lyme disease?How can I reduce my risk of Lyme disease?What questions should I ask my doctor?Where can I get more information about Lyme disease?
A history of Lyme disease, symptoms, diagnosis, treatment, and prevention. National Institute of Allergy and Infectious Diseases website. Available at: http://www.niaid.nih.gov/topics/lymeDisease/Pages/history.aspx. Updated March 29, 2011. Accessed September 26, 2012.
About Lyme disease. Lyme Disease website. Available at: https://www.lymedisease.org/lyme-basics/lyme-disease/about-lyme. Accessed September 26, 2012.
Cases by year. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/lyme/stats/chartstables/casesbyyear.html. Updated September 12, 2012. Accessed September 26, 2012.
Lyme disease. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/lyme/index.html. Updated July 26, 2012. Accessed September 26, 2012.
Lyme disease. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114365/Lyme-disease . Updated August 15, 2016. Accessed October 6, 2016.
- Reviewer: David L. Horn, MD
- Review Date: 11/2018
- Update Date: 12/20/2014