Lyme Disease Frequently Asked Questions (FAQ)
If you have not done so already, remove the tick with fine-tipped tweezers.
The chances that you might get Lyme disease from a single tick bite depend on the type of tick, where you acquired it, and how long it was attached to you. Many types of ticks bite people in the U.S., but only blacklegged ticks transmit the bacteria that cause Lyme disease. Furthermore, only blacklegged ticks in the highly endemic areas of the northeastern and north central U.S. are commonly infected. Finally, blacklegged ticks need to be attached for at least 24 hours before they can transmit Lyme disease. This is why it’s so important to remove them promptly and to check your body daily for ticks if you live in an endemic area.
If you develop illness within a few weeks of a tick bite, see your health care provider right away. Common symptoms of Lyme disease include a rash, fever, body aches, facial paralysis, and arthritis. Ticks can also transmit other diseases, so it’s important to be alert for any illness that follows a tick bite.
There is no credible scientific evidence that Lyme disease is spread through sexual contact. Published studies in animals do not support sexual transmission (Moody 1991; Woodrum 1999), and the biology of the Lyme disease spirochete is not compatible this route of exposure (Porcella 2001). The ticks that transmit Lyme disease are very small and easily overlooked. Consequently, it is possible for sexual partners living in the same household to both become infected through tick bites, even if one or both partners doesn’t remember being bitten.
Porcella SF, Schwan TG, 2001. Borrelia burgdorferi and Treponema pallidum: a comparison of functional genomics, environmental adaptations, and pathogenic mechanisms.external icon J Clin Invest 107: 651-6.
Woodrum JE, Oliver JH, Jr., 1999. Investigation of venereal, transplacental, and contact transmission of the Lyme disease spirochete, Borrelia burgdorferi, in Syrian hamsters.external icon J Parasitol 85: 426-30.
Moody KD, Barthold SW, 1991. Relative infectivity of Borrelia burgdorferi in Lewis rats by various routes of inoculation.external icon Am J Trop Med Hyg 44: 135-9.
There are no reports of Lyme disease being spread to infants through breast milk. If you are diagnosed with Lyme disease and are also breastfeeding, make sure that your doctor knows this so that he or she can prescribe an antibiotic that’s safe for use when breastfeeding.
Although no cases of Lyme disease have been linked to blood transfusion, scientists have found that the Lyme disease bacteria can live in blood from a person with an active infection that is stored for donation. Individuals being treated for Lyme disease with an antibiotic should not donate blood. Individuals who have completed antibiotic treatment for Lyme disease may be considered as potential blood donors. The Red Crossexternal icon provides additional information on the most recent criteria for blood donation.
No. Lyme disease is spread through the bite of a blacklegged tick (Ixodes scapularis or Ixodes pacificus) that is infected with Borrelia burgdorferi. In the United States, most infections occur in the following endemic areas:
- Northeast and mid-Atlantic, from northeastern Virginia to Maine
- North central states, mostly in Wisconsin and Minnesota
- West Coast, particularly northern California
Maps showing the distribution of human cases are based on where people live, which because of travel, is not necessarily where they became infected. Cases are sometimes diagnosed and reported from an area where Lyme disease is not expected, but they are almost always travel-related.
The lone star tick is primarily found in the southeastern and eastern United States. Lone star ticks do not transmit Lyme disease. However, you are correct to be concerned about this very aggressive species. The lone star tick (Amblyomma americanum) can spread human ehrlichiosis, tularemia, and Southern Tick-Associated Rash Illness (STARI).
The rash of STARI is a red, expanding “bull’ s eye” lesion that develops around the site of a lone star tick bite. The rash usually appears within seven days of tick bite and expands to a diameter of 8 centimeters (3 inches) or more. The rash should not be confused with much smaller areas of redness and discomfort that can occur commonly at tick bite sites. Unlike Lyme disease, STARI has not been linked to arthritis, neurological problems, or chronic symptoms. Nevertheless, the similarity between the STARI bull’s eye rash and the Lyme disease bull’s eye rash has created much public confusion. The pathogen responsible for STARI has not been identified.
In contrast, Lyme disease in North America is caused by a specific type of bacteria, Borrelia burgdorferi, which is transmitted by two species of blacklegged ticks, Ixodes scapularis and Ixodes pacificus. While blacklegged ticks exist in the southern U.S., their feeding habits in this region make them much less likely to maintain, sustain, and transmit Lyme disease.
Diagnosis, Testing, and Treatment
You may have heard that the blood test for Lyme disease is correctly positive only 65% of the time or less. This is misleading information. As with serologic tests for other infectious diseases, the accuracy of the test depends upon how long you’ve been infected. During the first few weeks of infection, such as when a patient has an erythema migrans rash, the test is expected to be negative.
Several weeks after infection, FDA cleared tests have very good sensitivity.
It is possible for someone who was infected with Lyme disease to test negative because:
- Some people who receive antibiotics (e.g., doxycycline) early in disease (within the first few weeks after tick bite) may not have a fully developed antibody response or may only develop an antibody response at levels too low to be detected by the test.
- Antibodies against Lyme disease bacteria usually take a few weeks to develop, so tests performed before this time may be negative even if the person is infected. In this case, if the person is retested a few weeks later, they should have a positive test if they have Lyme disease. It is not until 4 to 6 weeks have passed that the test is likely to be positive. This does not mean that the test is bad, only that it needs to be used correctly.
If you are pregnant and suspect you have contracted Lyme disease, contact your physician immediately. Untreated Lyme disease during pregnancy may lead to infection of the placenta and possible stillbirth. Fortunately, no serious effects on the fetus have been found in cases where the mother receives appropriate antibiotic treatment. In general, treatment for pregnant women with Lyme disease is similar to that of non-pregnant adults, although certain antibiotics, such as doxycycline, are not used because they can affect fetal development. There are no reports of Lyme disease transmission from breast milk. There are no published studies assessing developmental outcomes of children whose mothers acquired Lyme disease during pregnancy.
Maybe. The blacklegged ticks that transmit Lyme disease can sometimes also transmit babesiosis and anaplasmosis. Fortunately, Lyme disease and anaplasmosis are treated with the same antibiotics, so if you are receiving treatment for Lyme disease, anaplasmosis will be treated at the same time (Wormser et al. 2006). Babesiosis is a parasitic disease that is treated with different medications. If your Lyme disease symptoms do not seem to be going away after taking antibiotics, see your health care provider.
There is, however, a great deal of misinformation regarding tickborne coinfections on the internet. The possibility of having three or more tickborne infections or having pathogens such Bartonella or Mycoplasma (which have not been shown to be tickborne), is extremely unlikely.
The chance of having multiple tickborne infections depends on your location. Several studies have looked at the prevalence of these different organisms in ticks, though methods and locations are very different. Studies have shown that the rate of coinfection in blacklegged ticks varies by region from 1 to 28%. The most common coinfection in ticks is Borrelia burgdorferi (Lyme disease) and Anaplasma phagocytophilum (anaplasmosis). The frequency of tickborne coinfections in Lyme disease patients from endemic areas ranges from 4 to 45% (Swanson et al. 2006). From 2 to 12% of patients with early Lyme disease may also have anaplasma infection, and 2 to 40% of patients with early Lyme disease may also have babesia infection, depending on the region (Wormser, 2006).
Lantos PM, Wormser GP. Chronic coinfections in patients diagnosed with chronic Lyme disease: a systematic reviewexternal icon. Am J Med. 2014 Nov;127(11):1105-10. Epub 2014 Jun 12.
Swanson, et al. Coinfections acquired from Ixodes ticksexternal icon. Clin Microbiol Rev. 2006 Oct;19(4):708-27.
Wormser, Gary. Clinical practice. Early Lyme disease. N Engl J Med. 2006 Jun 29;354(26):2794-801.
Wormser et al. The clinical assessment, treatment, and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis: Clinical practice guidelines by the Infectious Diseases Society of Americaexternal icon Clin Infect Dis. 2006;43:1089-1134.
Probably not. First, you should only have an immunoblot (such as an FDA-approved Western Blot or striped blot) test done if your blood has already been tested and found reactive with an EIA or IFA.
Second, the IgM Western Blot test result is only meaningful during the first four weeks of illness. If you have been infected for longer than 4 to 6 weeks and the IgG Western Blot is still negative, it is highly likely that the IgM result is incorrect (e.g., a false positive). This does not mean that you are not ill, but it does suggest that the cause of illness is something other than the Lyme disease bacterium. For more information, see the in-depth discussion regarding testing for Lyme disease.
As with many infectious diseases, there is no test that can “prove” cure. Tests for Lyme disease detect antibodies produced by the human immune system to fight off the bacteria (Borrelia burgdorferi) that cause Lyme disease. These antibodies can persist long after the infection is gone. This means that if your blood tests positive, then it will likely continue to test positive for months or even years even though the bacteria are no longer present.
A research tool called PCR can detect bacterial DNA in some patients. Unfortunately, this is also not helpful as a test of whether the antibiotics have killed all the bacteria. Studies have shown that DNA fragments from dead bacteria can be detected for many months after treatment. Studies have also shown that the remaining DNA fragments are not infectious. Positive PCR test results are analogous to a crime scene – – just because a robbery occurred and the robber left his DNA, it doesn’ t mean that the robber is still in the house. Similarly, just because DNA fragments from an infection remain, it doesn’ t mean the bacteria are alive or viable.
No. The tests for Lyme disease detect antibodies made by the immune system to fight off the bacteria, Borrelia burgdorferi. Your immune system continues to make the antibodies for months or years after the infection is gone. This means that once your blood tests positive, it will continue to test positive for months to years even though the bacteria are no longer present. Unfortunately, in the case of bacterial infections, these antibodies don’t prevent someone from getting Lyme disease again if they are bitten by another infected tick.
No. Patients treated with antibiotics in the early stages of the infection usually recover rapidly and completely. Most patients who are treated in later stages of the disease also respond well to antibiotics, although some may have suffered long-term damage to the nervous system or joints. It is not uncommon for patients treated for Lyme disease with a recommended 2 to 4 week course of antibiotics to have lingering symptoms of fatigue, pain, or joint and muscle aches at the time they finish treatment. In a small percentage of cases, these symptoms can last for more than 6 months. These symptoms cannot be cured by longer courses of antibiotics, but they generally improve on their own, over time.
In areas where Lyme disease is common, most family practice physicians, general practitioners, and pediatricians are familiar with diagnosing and treating Lyme disease. If you have symptoms that suggest Lyme disease, or any other tick-borne infection, tell your doctor all these facts. Many doctors may not consider tick-borne diseases in diagnosing your illness unless you:
- Report being bitten by a tick, or
- Live in, or have recently visited, a tick-infested area.
In areas where Lyme disease is not common or for more complicated cases of Lyme disease, infectious disease specialists are often the best type of doctor to see. Please note that CDC cannot evaluate the qualifications and competence of individual doctors; however, the National Institutes of Health provides information about how to choose a doctor.external icon Additionally, your state medical boardexternal icon can help you find out if your health care provider is in good standing.
Lyme disease is caused by infection with the bacterium Borrelia burgdorferi. Although most cases of Lyme disease can be cured with a 2- to 4-week course of oral antibiotics, patients can sometimes have symptoms of pain, fatigue, or difficulty thinking that last for more than 6 months after they finish treatment. This condition is called ”Post-Treatment Lyme Disease Syndrome” (PTLDS). The term “chronic Lyme disease” (CLD) is also sometimes used; however, this term has been used to describe a wide variety of different conditions and therefore can be confusing. Because of the confusion in how the term CLD is employed, experts do not support its use (Feder et al., 2007external icon). For more information, see the National Institutes of Health — “Chronic Lyme Disease”external icon.
Each year, approximately 30,000 cases of Lyme disease are reported to CDC by state health departments and the District of Columbia. However, this number does not reflect every case of Lyme disease that is diagnosed in the United States every year.
Surveillance systems provide vital information but they do not capture every illness. Because only a fraction of illnesses are reported, researchers need to estimate the total burden of illness to set public health goals, allocate resources, and measure the economic impact of disease. CDC uses the best data available and makes reasonable adjustments—based on related data, previous study results, and common assumptions—to account for missing pieces of information.
To improve public health, CDC wants to know how many people are actually diagnosed with Lyme disease each year and for this reason has conducted two studies:
- Project 1 (Lyme Disease Testing by Large Commercial Laboratories in the United Statesexternal icon) estimated the number of people who tested positive for Lyme disease based on data obtained from a survey of clinical laboratories. Researchers estimated that 288,000 (range 240,000–444,000) infections occur among patients for whom a laboratory specimen was submitted in 2008.
- Project 2 (Incidence of Clinician-Diagnosed Lyme Disease, United States, 2005–2010) estimated the number of people diagnosed with Lyme disease based on medical claims information from a large insurance database. In this study, researchers estimated that 329,000 (range 296,000–376,000) cases of Lyme disease occur annually in the United States.
Results of these studies suggest that the number of people diagnosed with Lyme disease each year in the United States is around 300,000. Notably, these estimates do not affect our understanding of the geographic distribution of Lyme disease. Lyme disease cases are concentrated in the Northeast and upper Midwest, with 14 states accounting for over 96% of cases reported to CDC. The results obtained using the new estimation methods mirror the geographic distribution of cases that is shown by national surveillance.
As with most other reportable diseases, reporting requirements for Lyme disease are determined by state laws or regulations. In most states, Lyme disease cases are reported by licensed health care providers, diagnostic laboratories, or hospitals. States and the District of Columbia remove all personally identifiable information, then share their data with CDC, which compiles and publishes the information for the Nation. CDC has no way of linking this information back to the original patient.
CDC summarizes national surveillance data based on these reports, and publishes results in the CDC publication, the Morbidity Mortality Weekly Report. The latest summary was published in the Surveillance for Lyme Disease — United States, 2008–2015.
The goal of Lyme disease surveillance is not to capture every case, but to systematically gather and analyze public health data in a way that enables public health officials to look for trends and take actions to reduce disease and improve public health.
Final annual case counts are published when the year is over and all states and territories have verified their data, typically in the fall of the following year. Data through 2015 can be found in the MMWR Summary of Notifiable Diseases. Data from 2016 forward are found in CDC WONDER. Selected Lyme disease statistics, tables and charts are also available on the CDC Lyme disease website.
Reporting of all nationally notifiable diseases, including Lyme disease, is based on standard surveillance case definitions developed by the Council of State and Territorial Epidemiologists (CSTE) and CDC. The usefulness of public health surveillance data depends on its uniformity, simplicity, and timeliness. Surveillance case definitions establish uniform criteria for disease reporting and should not be used as the sole criteria for establishing clinical diagnoses, determining the standard of care necessary for a particular patient, setting guidelines for quality assurance, or providing standards for reimbursement. The national surveillance case definition for Lyme disease is available on CDC’ s web site.
Lyme Corps was a train-the trainer program for Lyme disease focused on prevention and early recognition of Lyme disease and other tickborne diseases. It ran from 2012 to 2016.
Lyme Corps members consisted of medical and public health students chosen annually from a selected university system in areas of high Lyme disease incidence. The members facilitated Lyme disease education in conjunction with local health care systems, health departments, schools, and community events (farmers’ markets, trail runs, etc.). Universities and states involved in Lyme Corps included:
- Drexel University/Philadelphia Dept. of Health, 2012-2013
- University of Virginia/James Madison Universityexternal icon/Virginia Dept. of Health, 2013-2014
- University of Vermontexternal icon/Vermont Dept. of Health, 2014-2015
- University of Maryland/Johns Hopkins University/Uniformed Services University of the Health Sciences/ Maryland Dept. of Health and Mental Hygiene, 2015-2016
Lyme Corps participants have also assisted with the following research projects:
- Butler AD, Carlson ML, Nelson CA. Use of a tick-borne disease manual increases accuracy of tick identification among primary care providers in Lyme disease endemic areas.external icon Ticks Tick Borne Dis. 2017 Feb;8(2):262-265.
- Conant JL, Powers J, Sharp G, Mead PS, Nelson CA. Lyme disease testing in a high-incidence state: Clinician knowledge and patternsexternal icon. Am J Clin Pathol. 2018 Feb 17;149(3):234-240.
- Hu SY, Starr JA, Gharpure R, Mehta SP, Feldman KA, Nelson CA. Knowledge and prevention of tickborne diseases among Hispanic and non-Hispanic residents of Maryland and Virginiaexternal icon. Zoonoses Public Health. 2019 Sep 3. [Epub ahead of print]
- Nelson CA, Hayes CM, Markowitz MA, Flynn JJ, Graham AC, Delorey MJ, Mead PS, Dolan MC. The heat is on: Killing blacklegged ticks in residential washers and dryers to prevent tickborne diseases.external icon Ticks Tick Borne Dis. 2016 Jul;7(5):958-963.
- Nelson CA, Starr JA, Kugeler KJ, Mead PS. Lyme disease in Hispanics, United States, 2000-2013. Emerg Infect Dis. 2016 Mar;22(3).
Lyme Corps members were not federal employees; their views and opinions did not necessarily represent the official position of the Centers for Disease Control and Prevention or the U.S. Government.
CDC has a program of service, research, and education focusing on the prevention and control of Lyme disease. Activities of this program include:
- Maintaining and analyzing national surveillance data for Lyme disease
- Conducting epidemiologic investigations
- Offering diagnostic and reference laboratory services
- Developing and testing strategies for the control and prevention of this disease in humans
- Supporting education of the public and health care providers
In addition, the TickNET program supports research that contributes to the understanding of tickborne diseases.