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Lyme Disease

Lyme Disease

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Lyme disease is a bacterial infection caused by the spirochete Borrelia burgdorferi, transmitted through the bite of infected black-legged ticks, also known as deer ticks. While it can cause serious health issues, it's treatable with antibiotics, and with early diagnosis and treatment, most people make a full recovery.

Ticks carrying Lyme disease are present in countries worldwide, such as in Asia and Europe, but particular regions of the United States have some of the highest rates of Lyme disease-carrying ticks.

This article will provide an in-depth look at Lyme disease, including its causes, symptoms, diagnosis, and treatment options, as well as tips on how to protect yourself and others from tick bites.

  • What is Lyme Disease?
  • Lyme Disease bacteria
  • Causes of the Lyme Disease
  • Symptoms of the Lyme Disease
  • Lyme Disease treatment
  • Lyme Disease Prevention
  • Lyme Disease Key takeaways

What is Lyme disease?

Lyme disease is an infection caused by bacteria of the genus Borrelia, transmitted by vector ticks known as deer ticks or black-legged ticks.

Black legged tick Deer tick Lyme Disease vector StudySmarterFig. 1. Black-legged or deer tick, the vector for Lyme disease transmission. Source: Flickr.

Lyme disease can cause a wide range of symptoms, the most common of which is a bulls-eye rash that appears at the site of the tick bite. Apart from that, Lyme disease can also cause fever, headaches or fatigue.

If left untreated, Lyme disease can be a dangerous illness. Luckily, treatment with antibiotics usually resolves the infection. If you suspect you have Lyme disease, it's very important that you seek medical attention as soon as possible.

Lyme disease bacteria

The causative agent of Lyme disease are bacteria from the genus Borrelia, namely Borrelia burgdorferi and sometimes also Borrelia mayonii.

Members of the genus Borrelia are spirochetes. Spirochetes are a family of bacteria with a unique spiral shape, instead of the spherical shape seen in cocci or the rod shape seen in bacilli. Most spirochetes, Borrelia included, stain very weakly pink and are considered weakly gram-negative!

Other spirochete bacteria include Treponema which causes syphilis and Leptospira which causes leptospirosis!

lyme disease spirochete shape deposit photosFig. 2. Spirochete shape. DepositPhotos.

Causes of Lyme disease

The deer or black-legged tick, scientific name Ixodes scapularis, is the specific tick that acts as the vector and most common agent of transmission of B. burgdorferi and, therefore, Lyme disease.

Vector - in microbiology and medicine, a vector is an organism that helps in transmitting a pathogen from one organism to another.

As vectors, deer ticks transfer B. burgdorferi from animal reservoirs like cows, wild mice, and deer (hence the name, deer tick), to human beings. When humans get bitten by a deer tick carrying B. burgdorferi they can become infected with Lyme disease.

Usually, the tick needs to be attached to human skin for 48-36 h to transmit the bacteria and infect the human. The risk for transmission increases the longer the tick is attached to the human host.

Lyme Disease Lyme disease transmission Saltmann quarterlyFig. 3. Lyme disease transmission. Saltman Quarterly.

It is important to note that not all tick bites result in Lyme disease and that the majority of tick bites do not transmit the bacteria. Regardless, knowing how to protect yourself from tick bites, how to spot the symptoms of Lyme disease, and how to seek treatment if you suspect you have it is key to a full recovery.

The risk of getting bitten by a tick containing B. burgdorferi or B. mayonii is not the same in all parts of the world. As mentioned above, B. burgdorferi has a specific geographical distribution.

For example, in the US people in the states like Colorado, Wyoming, Montana, and Idaho, are extremely unlikely to get Lyme disease. On the other hand, those who live in brushy, forested areas of the Upper Midwest, and especially the North East, are at significant risk of coming in contact with Lyme disease-infested ticks.

Lyme disease symptoms

Lyme disease occurs in stages, and the symptoms can vary throughout these stages. If treated, not all the stages will occur, however, there are some classic symptoms in each stage that are important to know. The stages of Lyme disease are:

  1. The early stage
    1. The early localized stage*
    2. The early disseminated stage.
  2. The late stage

*A localized disease is one that is limited in the parts of the body it is affecting. Depending on the nature of the disease, if the infection spreads, it can become a disseminated disease. A disseminated disease affects multiple organs or even whole body systems. Usually, disseminated diseases are more dangerous and people who have them are more medically unstable because many of the affected organs are the ones required for life - like the brain and the heart.

Stage 1 - early localized stage

After someone is bitten by a tick carrying B. burgdorferi and the bacteria manage to colonise the new host, within a week or two a bulls-eye rash forms. This rash is the primary symptom of the early localized stage of Lyme disease and it is called erythema migrans.

Erythema migrans may not look like any other rash you have seen or felt in your life. It has a unique appearance, shaped like a bulls-eye (Fig. 3). This "targetoid" rash usually develops slowly over weeks, and usually doesn't itch (though it can).

Alongside erythema migrans, people in the early localized stage usually have what feels like the flu: fever, headache, sore muscles, tiredness, and what is called "general malaise", which means generally feeling sick.

Lyme disease early localized lyme healthlineFig. 4. Early localized Lyme disease. Healthline.

An important fact to note is that not everyone who gets infected with Lyme disease experiences the symptoms of the early localized stage. We don't know why, but about 20% of people with Lyme disease don't have erythema migrans in stage 1. Only about 80% do. So we cannot rule out Lyme disease, just because someone did not have the classic bulls-eye rash.

Stage 2 - early disseminated stage

Symptoms of stage 2 Lyme disease - the early disseminated stage - can be thought of with the following acronym: CANS.

  • C = for cardiovascular symptoms. Lyme disease typically causes inflammation of the heart known as carditis. It also often causes abnormal rhythms of the heart known as arrhythmia.
  • A = for arthritis. Lyme disease causes a migratory polyarthralgia. This long phrase simply means a spreading pain in multiple joints (like elbows and knees).
  • N = for neurologic symptoms. Lyme disease affects nerves mainly, like nerves in the arms and legs which can lead to tingly sensations. Nerves in the face can also be affected, causing paralysis and drooping of the face that resembles Bell's Palsy.
  • S = for skin. Lyme disease in the early disseminated phase affects the skin by causing erythema migrans, but instead of just one, multiple.

Early disseminated Lyme disease healthlineFig. 5. Early disseminated Lyme disease symptoms. Healthline.

  • Carditis
  • Arrhythmia
  • Migratory polyarthralgia
  • Tingling feeling
  • Bell's palsy
  • Multiple erythema migrans
Table 1. Summary of the CANS symptoms of the early disseminated stage of Lyme disease.

Stage 3 - late stage

It would be a shame for someone to reach the late stage of Lyme disease without any treatment. Unfortunately, this does sometimes occur. When it does, the typical symptoms that appear as consolidations of two of the symptoms from the early disseminated stage - arthritis and neurologic symptoms. However, in the late stage, the symptoms are worse, and sometimes permanent.

Late stage Lyme disease starts sometimes months, usually years after the first tick bite.

Chronic Lyme disease

When a patient with Lyme disease reaches the late stage of the disease without treatment, this can become chronic.

Lyme disease late stage lyme disease medical news todayFig. 6. Late stage Lyme Disease. Medical News Today.

The patient with chronic Lyme disease will suffer the following long-term or permanent symptoms:

  • Chronic arthritis that may not go away. Just like in the early disseminated stage, it typically occurs in big joints like the elbows and knees. It can be intermittent - meaning it waxes and wanes- or it can be persistent - meaning it is always present.

  • Neurologic symptoms: these are the most devastating. Lyme disease may cause:

    • Meningitis - which is inflammation of the brain leading to fever, and sometimes seizures.

    • Permanent brain damage and decreased IQ.

    • Behavioural changes and depression.

    • Walking-style changes (walking-style is known as gait).

    • Painful, tingly, hypersensitive nerve endings in the arms and legs.

Lyme disease treatment

Luckily, Lyme disease is a curable disease. If caught early on, the patient can recover fully, though they can suffer from lingering effects for 6 months after the treatment is completed.

It's important to start treatment for Lyme disease as soon as possible, as the longer it is left untreated, the worse it becomes, progressing from early to late stage disease. The symptoms of late-stage Lyme disease are often permanent, so it's important to avoid the progression of the disease as much as possible.


The treatment for Lyme disease is antibiotics. Remember, Lyme disease is caused by a bacterial pathogen - B. burgdorferi, so naturally an antibacterial (same thing as an antibiotic) will be used to treat it. Often, two antibiotics are given to tackle the various symptoms of Lyme disease.

For example, the antibiotic amoxicillin is given to treat erythema migrans and Lyme disease arthritis, while ceftriaxone is given to treat the heart problems and neurological problems caused by Lyme disease.

Is Lyme disease curable?

Lyme disease is a curable condition with prompt and appropriate treatment. The recommended treatment for early stages of Lyme disease is a course of antibiotics, usually given for 14 to 21 days.

It's important to note that most people treated for Lyme disease with antibiotics in the early stages of the infection will make a full recovery. In some cases, however, even with treatment, some people may continue to have symptoms such as fatigue, muscle aches, and joint pain. These symptoms are known as post-treatment Lyme disease syndrome (PTLDS) and they are usually self-limiting and resolve without specific treatment.

As mentioned above, if the disease is left without treatment until the late stages, some symptoms may become chronic even despite treatment. This is why it's crucial to catch the symptoms as soon as possible, but also strive to prevent contagion as well as we can.

Lyme disease prevention

Due to the potential severity of the symptoms of Lyme disease and the lack of vaccination against it, preventing tick bites is key to preventing Lyme disease. How do we best prevent tick bites (or deal with new tick bites)?

  • AVOID: If you can, avoid areas known to have a lot of ticks. This is tricky if you live in the woods of New England, for example, which takes us to the next point.
  • COVER: When you are outside in an area known to have ticks, wear protective clothing, such as long sleeves or long trousers.
  • REPEL: Use bug sprays and tick repellant when you are outside, to kill and repel ticks.
  • INSPECT: When you come inside from a long day outside, inspect your body for ticks. They may still be on your skin.REMOVE: If you find a tick on your body, remove them quickly but very carefully with tweezers (or ask another person for help). Grab the tick as close to the head as possible and pull firmly but slowly away from your skin. Try not to crush them and don't wait for them to fall off on their own. Once you removed the tick, clean the wound.


A vaccine for humans against Lyme disease is not currently available. Several years ago, from the 1990s to the early 2000s, a vaccine against Lyme did exist, but it was discontinued. For now, the best method of preventing Lyme disease is by preventing tick bites.

We hope you found the article useful and are now aware of what you should do to avoid getting Lyme disease, and also what you should look for when you think you might have it.

Lyme Disease - Key takeaways

  • Lyme disease is caused by the spirochete bacteria Borrelia burgdorferi and sometimes by Borrelia mayonii.
  • Lyme disease is transmitted by ticks, and its animal hosts include mice, cows, and deer.
  • Initially, Lyme disease causes a bull's eye-shaped rash called erythema migrans.
  • In later stages, Lyme disease causes issues to the heart, the nerves, the brain, and the joints.
  • There is no vaccine for Lyme disease, but it can be treated in the early stages with antibiotics. For prevention, we must avoid tick bites and be mindful of the 48-36 h usually needed for a tick to transmit the bacteria to a human.
  • Late stage Lyme disease can have permanent arthritic and neurological effects on a patient.

Frequently Asked Questions about Lyme Disease

Lyme disease is a contagious infection caused by Borrelia bacteria. People usually get infected through the bite of a tick carrying the disease. Symptoms include rashes, fever, headaches and fatigue.

Yes, Lyme disease can be cured with the use of antibiotics. However, some patients may experience persistent symptoms even after treatment for about 6 months.

Lyme disease cannot be passed on from an infected to a healthy person. The mode of transmission is through the bite of a bacteria-carrying tick.

Untreated infection during pregnancy can mean that the placenta gets infected, but transmission from mother to fetus is rare.

People can only get Lyme disease if they are bitten by an infected tick.

Lyme disease is caused by bacteria from the Borrelia genus, namely Borrelia burgdorferi and rarely also Borrelia mayonii.

Lyme disease symptoms include rashes (specifically erythema migrans), fever, headaches and fatigue.

Final Lyme Disease Quiz

Lyme Disease Quiz - Teste dein Wissen


What shape do Borrelia bacteria have?

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What is the first stage of Lyme disease called?

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Early localized

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What is the second stage of Lyme disease called?

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Early disseminated stage

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What is the third stage of Lyme disease called?

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Late stage

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What does the acronym CANS stand for when discussing symptoms of disseminated Lyme disease?

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C for Cardiovascular

A for arthritis

N for nervous system

S for skin

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What kind of effect might happen to the face of someone with early disseminated Lyme disease?

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Facial nerve palsy - their face may droop

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What is the treatment for Lyme disease

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What is a vector in microbiology?

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An organism that helps transmit a pathogen to other organisms.

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What is the vector for Lyme disease transmission?

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The deer tick, Ixodes scapularis

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Which of the following effects on bones is most commonly caused by Lyme disease?

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Painful joints

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People in which state are most likely to be at risk for Lyme disease?

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New Hampshire

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What parts of the USA have higher rates of Lyme disease?

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North East and Upper Midwest.

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If you find a tick on your skin after a long day outside you should.......

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Remove it

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Within what period of time does erythema migrans first appear after getting bitten by a tick and contracting Lyme disease?

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about 2 weeks

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Does everyone who has Lyme disease have the classic bulls-eye rash?

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