Also Known As
Borrelia burgdorferi Infection
Borrelia mayonii Infection
This article was last reviewed on
This article waslast modified on
December 28, 2017.
What is Lyme disease?

Lyme disease is an infection caused by the bacteria Borrelia burgdorferi and Borrelia mayonii, which are carried primarily by the deer tick, also known as the black-legged tick. People bitten by an infected tick may develop an inflammatory condition, which first affects the skin and then may spread to the joints, nervous system, and other body systems.

The ticks that cause Lyme disease are tiny, about the size of the head of a pin or a speck of dirt. They can be found anywhere on the body but tend to attach themselves to areas such as the scalp and groin. People who have exposure to ticks but have not been bitten will not be infected by Borrelia, and many who are bitten will not develop Lyme disease. This is because not every tick is infected and because it can take the tick from 24 to 72 hours after attachment to transmit the bacteria.

Lyme disease is found throughout the northern hemisphere, but the strains of bacteria that cause it and the insects that carry it vary from region to region. In the U.S., Lyme disease is the most commonly reported illness spread by insects (vectorborne). It was the fifth most common Nationally Notifiable disease in 2013, but this does not apply across all states. Lyme disease occurs most frequently in northeastern and midwestern states. The vast majority of the cases occur in the spring and summer when people spend more time outside and the ticks are active.

According to statistics available from the Centers for Disease Control and Prevention (CDC), about 30,000 cases of Lyme disease are reported in the U.S. each year. Roughly 95% of Lyme disease cases are reported from 14 states (see map on this CDC web page).

However, the CDC estimates that the actual number of people in the U.S. who are diagnosed with Lyme disease each year is roughly 10 times the number reported. The higher estimate of 300,000 cases annually is based on data from ongoing studies. This higher estimate does not mean that many Lyme disease cases go untreated, says the CDC, only that they may go unreported to state and federal public health laboratories. Low disease estimates from under-reporting can create an inaccurate picture of the scope of a public health problem such as this, especially when the incidence may be so much higher than previously thought. Better estimates obtained from the ongoing studies can help increase awareness of the issue, providing additional incentive for the general public, government, and medical community to focus on this disease and its prevention.

Post-Treatment Lyme Disease Syndrome
For some people with Lyme disease, after treatment with antibiotics, there are lingering symptoms of fatigue, pain, or joint and muscle aches. For a small percentage of cases, these symptoms can last over 6 months. This is known as Post-Treatment Lyme Disease Syndrome (PTLDS). The exact cause of PTLDS is unknown. PTLDS is sometimes mistakenly referred to as chronic Lyme disease. Research is ongoing to better understand the cause of this syndrome. For more information, see the CDC's web page on PTLDS.

Accordion Title
About Lyme Disease
  • Signs and Symptoms

    Lyme disease occurs in stages, starting with early localized Lyme disease and progressing to early disseminated and then to late Lyme disease.

    Early signs and symptoms can develop from 3 to 30 days after the tick bite and may include:

    Characteristic rash of Lyme disease

    • Rash at the site of the tick bite: one of first symptoms is usually a rash that appears a few days to a month after the bite. Up to 75% of those infected with Borrelia burgdorferi will develop the characteristic circular rash called erythema migrans. It typically spreads outward from the bite site and lasts for several weeks. The rash may reach several inches in diameter and begin to look like a "bulls-eye." Some people may develop multiple red rashes and others may not have, or remember having, a rash. Note that it is common to see a small bump or redness that develops soon after a tick bite that may look like a mosquito bite. However, this bump or redness generally goes away in one or two days and is not a sign of Lyme disease.
    • Headache
    • Fatigue
    • Fever and chills
    • Muscle and joint aches
    • Swollen lymph nodes


    Borrelia mayonii seems to produce other symptoms, including nausea and vomiting, and may cause a rash that is more spread out (diffuse) and lacks the bull's eye target appearance.

    If left untreated, additional signs and symptoms may emerge after several days to months after a tick bite, including:

    • Muscle and joint pain (may be intermittent)
    • Facial weakness and paralysis (Bell's palsy)
    • Numbness and pain in arms and legs
    • Neck stiffness and severe headaches (meningitis)
    • Chest pain and irregular heart beat (rare)
    • Eye irritation, redness, pain, and blurred vision (rare)
    • Intermittent arthritis with joint pain and swelling, especially in larger joints like the knees
    • Memory loss, difficulty concentrating, and changes in sleep patterns
    • Spells of dizziness or shortness of breath
    • Shooting pains, numbness, or tingling in the hands or feet
    • Inflammation of the brain and/or spinal cord
  • Tests

    A health practitioner may diagnose Lyme disease based upon the person's clinical symptoms, such as the presence of an erythema migrans (EM) or "bull's-eye" rash, a history of a tick bite, and/or residence in or a visit to one of the areas of the country where Lyme disease is most commonly found. In cases where history and symptoms are sufficient to diagnose Lyme disease, a laboratory test is not usually ordered.

    Lyme disease testing is ordered when someone has signs and symptoms that suggest the person has contracted the disease. The preferred test is a blood test to detect the presence of antibodies to the bacteria. If a person has central nervous system symptoms, such as meningitis, then testing may be performed on cerebrospinal fluid (CSF). The Centers for Disease Control and Prevention (CDC) does not recommend Lyme disease testing for people who do not have any symptoms.

    • Borrelia IgM and/or IgG antibodies – may also be positive with infections caused by other bacteria similar to Borrelia, such as the bacteria that cause syphilis
    • Borrelia western blot – ordered to confirm positive or indeterminate antibody test results
    • In special cases, PCR (polymerase chain reaction) testing may be performed on a sample because it is a more sensitive way of detecting an infection with Borrelia. However, this is not an FDA cleared or approved test method and it is not widely available. The CDC does not currently recommend PCR testing for the diagnosis of Lyme disease.
  • Treatment and Prevention

      Treatment
      Lyme disease is usually treated with oral antibiotics for 2-4 weeks. Some people may require intravenous antibiotics. In most cases, those with Lyme disease recover rapidly and completely. In some cases, especially with late-stage Lyme disease, some joint pain and neurological damage may persist. For more on Lyme disease treatment, see this CDC web page.

      Prevention
      Currently, there is no vaccine available to prevent Lyme disease, but standard precautions to avoid exposure to ticks and tick bites can greatly reduce the risk of becoming infected. These include:

      • Wearing light-colored long-sleeved shirts and pants
      • Tucking pant legs into socks
      • Wearing closed shoes
      • Avoiding wooded and grassy areas, especially in spring and early summer, walking in the center of trails
      • Using a tick repellant that contains 20-30% DEET (N, N-diethyl-m-toluamide) or permethrin
      • Checking for ticks after spending time outside
      • Removing ticks as soon as they are found
      • Pets should also be routinely checked for ticks.
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    NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.

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