Lyme disease is a bacterial infection that a person can acquire from the bite of an infected tick. It is rarely fatal, but the condition can affect the joints, heart, and nervous system.

Black-legged or western black-legged ticks can transmit Lyme disease. Black-legged ticks live in the northeastern, north-central, and mid-Atlantic United States. Western black-legged ticks live on the Pacific coast.

Ticks first acquire the disease by feeding from an animal infected with the bacterium Borrelia burgdorferi. They then pass this on by biting a human. The tick must be attached for 36–48 hours to transmit Lyme disease.

Lyme disease often begins with a unique rash that forms a widening circle around the tick bite. It may look like a target or bull’s eye. A person may experience flu-like symptoms and issues with their joints, heart, and nervous system.

Antibiotics can treat Lyme disease, and early treatment prevents more serious issues from developing.

This article examines whether Lyme disease is fatal, treatments, complications, the outlook for the disease, and when to contact a doctor.

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Deaths from Lyme disease are extremely rare.

Lyme carditis is a condition that can develop from Lyme disease and interrupt the usual electrical functioning of the heart. It occurs in about 1–10 out of every 100 cases of Lyme disease in the U.S.

In some cases of Lyme carditis, a condition called heart block develops when disruption occurs between signals between the upper and lower chambers of the heart.

According to the Centers for Disease Control and Prevention (CDC), 11 fatal cases of Lyme carditis occurred worldwide between 1985 and 2019.

What is the outlook with treatment?

Oral or intravenous antibiotics treat Lyme disease. Early treatment should clear up the infection and prevent the spread of bacteria.

In later stages, when the bacteria has spread and caused symptoms, antibiotics can still help reduce symptoms. However, they may remain for years or never fully resolve.

Learn more about how doctors cure Lyme disease.

What is the outlook without treatment?

Untreated Lyme disease may mean the bacteria lie dormant in different parts of the body for some time. Weeks, months, or years later, they may become active again, leading to issues with the joints, brain, heart, other organs, or the nervous system.

When these symptoms become difficult to treat and resolve, doctors call it post-treatment Lyme disease (PTLD) or chronic Lyme disease (CLD).

With quick treatment, Lyme disease usually clears with antibiotics. If it goes untreated, there may be long-term complications, including:

Learn more about chronic Lyme disease.

The International Lyme and Associated Diseases Society (ILADS) defines CLD as a multisystem illness that causes symptoms for a minimum of 6 months.

Estimates of the proportion of people with Lyme disease who experience CLD range from 5–30%.

With early treatment, the outlook for Lyme disease is good. Most people respond well to antibiotic treatment.

People should consult a doctor for evaluation if any illness develops within a few weeks following a tick bite. Ticks can also transmit other illnesses, so a person should inform the doctor about any symptoms.

Some common symptoms of Lyme disease include:

The doctor will want to know a person’s location at the time of the bite and how long the tick was attached.

Learn more about the symptoms of Lyme disease.

Lyme disease is a serious but rarely fatal condition caused by the bite of the black-legged or western black-legged tick. The tick must carry the bacterium B. burgdorferi and attach to a person for 36–48 hours to transmit Lyme disease.

Antibiotics help treat Lyme disease without lasting effects. Without treatment, it can cause long-term effects, including arthritis and issues with organs and the neurological system.

Fatalities from Lyme disease are very rare. Between 1985 and 2019, 11 people worldwide died due to the heart condition Lyme carditis.