Lyme disease
Overview
Lyme disease is a tick-borne bacterial infection caused by members of the Borrelia burgdorferi sensu lato complex. In North America, most cases are caused by Borrelia burgdorferi sensu stricto, while Borrelia mayonii causes a small number of cases. In Europe and parts of Asia, other species, including Borrelia afzelii, Borrelia garinii, and Borrelia bavariensis, also cause Lyme disease. The infection is most commonly transmitted through the bite of infected black-legged ticks (deer ticks).
Most people recover with appropriate antibiotic treatment. However, some continue to experience persistent symptoms such as fatigue, pain, or cognitive difficulties after treatment. This condition is known as post-treatment Lyme disease syndrome (PTLDS). The term chronic Lyme disease is also used by some patients and clinicians, but it does not have a universally accepted medical definition and is not considered synonymous with PTLDS.
Common Symptoms
Fever, chills, headache, fatigue, erythema migrans (expanding rash), muscle and joint aches, swollen lymph nodes, neck stiffness, facial palsy, Lyme arthritis, intermittent pain in the tendons, muscles, joints, or bones, heart palpitations or irregular heartbeat, dizziness, shortness of breath, meningitis or brain and spinal cord inflammation, nerve pain, numbness or tingling in the hands or feet, cognitive or other neurological symptoms, eye inflammation, and liver inflammation.
Coexisting Diseases and Conditions
Lyme carditis, Lyme arthritis, Bell’s palsy, meningitis, hepatitis, babesiosis, anaplasmosis, ehrlichiosis, bartonellosis, and rickettsial infections.
Risk Factors and Prevalence
People who live in or spend time in wooded, brushy, or grassy areas where infected ticks are present are at increased risk of Lyme disease. Wearing protective clothing, using tick repellents, and performing thorough tick checks after outdoor activities can reduce the risk of infection. In most cases, transmission requires the tick to remain attached for approximately 36–48 hours or longer, although transmission time can vary depending on the Borrelia species and other factors.
Lyme disease is the most common vector-borne disease in North America and Europe, with hundreds of thousands of people treated each year in the United States.
Recent Research
- Systematic comparisons between Lyme disease and post-treatment Lyme disease syndrome in the US with administrative claims data (2023)
- Metabolic response in patients with post-treatment lyme disease symptoms/syndrome (2021)
- Post-treatment lyme disease syndrome: Need for diagnosis and treatment (2021)
- Efficacy of double-dose dapsone combination therapy in the treatment of chronic lyme disease/post-treatment lyme disease syndorme (PTLDS) and associated co-infections: A report of three cases and retrospective chart review (2020)
Sources
- Sources
Centers for Disease Control and Prevention. (2021, May 28). Lyme Disease. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/index.html
Centers for Disease Control and Prevention. (2021, January 15). Signs and Symptoms of Untreated Lyme Disease. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/signs_symptoms/index.html
- Ostfeld, R. S. (1997). The Ecology of Lyme-Disease Risk: Complex interactions between seemingly unconnected phenomena determine risk of exposure to this expanding disease. American Scientist, 85(4), 338–346. http://www.jstor.org/stable/27856811
International Lyme and Associated Diseases Education Foundation. (2018, July 13). Lyme Disease FAQ. ILADEF. https://iladef.org/education/lyme-disease-faq/
U.S. Department of Health and Human Services. (2018, November 16). Lyme Disease Co-Infection. National Institute of Allergy and Infectious Diseases. https://www.niaid.nih.gov/diseases-conditions/lyme-disease-co-infection
LymeDisease.org. (n.d.). People with Lyme disease co-infections experience more severe illness. LymeDisease.org. https://www.lymedisease.org/lyme-basics/co-infections/about-co-infections/
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Bellafiore, J., Mahrous, A., Gurumurthy, V., Capitle, E., & Schutzer, S. E. (2026). Retrospective Case Series of Ocular Lyme Disease, 1988-2025. Emerging infectious diseases, 32(1), 15–20. https://doi.org/10.3201/eid3201.250769
Ma, W., Li, J., Gao, L., Wu, X., Ma, W., Yang, J., Zhong, L., Song, J., Peng, L., Bao, F., & Liu, A. (2025). Comparison of the Serodiagnostic Accuracy Tests for Lyme Disease in Adults and Children: A Network Meta-Analysis. Pathogens (Basel, Switzerland), 14(8), 784. https://doi.org/10.3390/pathogens14080784
Popov, G., Bashchobanov, D., & Andonova, R. (2026). Tick-Borne Co-Infection in Lyme Disease: Clinical Impact, Diagnostic Challenges, and Therapeutic Perspectives. Microorganisms, 14(2), 325. https://doi.org/10.3390/microorganisms14020325
Priya, S., Sridhar, S. B., Shareef, J., Wadhwa, T., Balusamy, B., Meenakshi, D. U., Sundram, S., & Malviya, R. (2026). Epidemiology, diagnosis and emerging therapies for Lyme disease of the Northern Hemisphere. International journal of emergency medicine, 19(1), 102. https://doi.org/10.1186/s12245-026-01182-5