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In the early 1970s, a mysterious group of rheumatoid arthritis cases occurred among children in Lyme, Connecticut, and two neighboring towns. Puzzled, researchers looked at several possible causes, such as contact with germs (microbes) in water or air. Realizing that most of the children with arthritis lived and played near wooded areas, they then focused their attention on deer ticks.
Researchers knew that the children’s first symptoms typically started during the summer, the height of tick season. Several children reported having a skin rash just before developing arthritis, and many of them recalled being bitten by a tick where the rash appeared. By the mid-1970s, researchers began describing the signs and symptoms of this new disease, now termed Lyme disease, to help physicians diagnose patients.
However, it was not until 1981 that NIAID researchers at Rocky Mountain Laboratories (RML) in Hamilton, Montana, identified the cause of Lyme disease and discovered the connection between the deer tick and the disease. European researchers had described a skin rash similar to that of Lyme disease in early 20th-century medical literature. Willy Burgdorfer, Ph.D., a NIAID scientist studying Rocky Mountain spotted fever, also caused by a tick bite, wondered whether the European rash, called erythema migrans (EM), and Lyme disease might have the same cause. Along with his RML colleague Alan Barbour, M.D., Dr. Burgdorfer continued to study spiral-shaped bacteria, or spirochetes, from infected deer ticks. In November 1981, the two scientists found that a spirochete caused both Lyme disease and EM. The spirochete was later named Borrelia burgdorferi in honor of Dr. Burgdorfer’s role in its discovery.
Read more about their discovery in the NIAID research feature.
Typically, the first symptom of Lyme disease is a rash known as erythema migrans, which starts as a small red spot at the site of the tick bite and gets larger over a period of days or weeks, forming a circular or oval-shaped red rash. The rash may look like a bull's eye, appearing as a red ring around a clear area with a red center. It appears within a few weeks of a tick bite and usually occurs at the place of the bite. The rash can range in size from that of a small coin to the width of a person's back. As infection spreads, rashes can appear at different sites on the body. The rash is often accompanied by other symptoms, such as fever, headache, stiff neck, body aches and fatigue. Although these symptoms may be like those of common viral infections, such as the flu, Lyme disease symptoms tend to last longer or may come and go over time.
Some people who have Lyme disease may develop arthritis or nervous system problems and more rarely, heart problems. Lyme disease may also cause eye inflammation, hepatitis (liver disease), and severe fatigue. However, these problems usually only appear in conjunction with other symptoms of the disease.
Healthcare providers may have difficulty diagnosing Lyme disease because many of its symptoms are similar to those of other illnesses, such as the flu. The bull's eye rash is the only symptom that is unique to Lyme disease, but not everyone infected with Lyme bacteria develops the rash. Research supported by the National Institutes of Health and CDC suggest that a tick must be attached to the body for at least 36 hours to transmit Lyme disease. Although transmission cannot occur without the tick bite, many people may not remember being bitten because the deer tick is tiny and its bite is usually painless.
If a person has symptoms of Lyme disease but does not have the distinctive rash, healthcare providers will rely on a detailed medical history. The medical history includes whether symptoms first appeared during the summer months, if the person had been outdoors in an area where Lyme disease is common, and whether the person was bitten by a tick, along with a careful physical exam and laboratory tests to check for the presence of antibodies to B. burgdorferi to help provide a diagnosis.
It takes a few weeks for someone infected with B. burgdorferi to produce antibodies against the bacteria. Healthcare providers frequently use one of two antibody tests as a first-level screening. The screening tests are designed to be very "sensitive," meaning that almost everyone who has Lyme disease and some people who do not, will test positive. If the screening test is negative, it is highly unlikely that the person has Lyme disease and no further testing is needed. If the screening test is positive or indeterminate, a second, different test known as a Western blot test should be performed. Used appropriately, this test is designed to be "specific," meaning that it will usually be positive only if a person is truly infected. If the Western blot is negative, it suggests that the first test was a false positive.
The Centers for Disease Control and Prevention (CDC) does not recommend a Western blot test without conducting the first-level blood screening. Using the Western blot alone increases the potential for false positive results, which may cause individuals to be treated for Lyme disease when they do not have it and, subsequently, not receive treatment for the true cause of their illness. It is also noteworthy that some laboratories offer Lyme disease testing using assays whose accuracy and clinical usefulness have not been adequately established. Tests that use urine or other bodily fluids (other than blood) to diagnose Lyme disease have not been approved by the Food and Drug Administration.
Antibiotics are prescribed to effectively treat Lyme disease. These medicines can help speed healing of the erythema migrans rash and keep symptoms, such as arthritis and nervous system problems, from developing. In general, the sooner treatment begins after infection, the quicker and more complete the recovery. Treatment for pregnant women is similar to treatment for others, but certain antibiotics are not used because they may affect the fetus.
After receiving treatment for Lyme disease, patients may still experience muscle or joint aches and nervous system symptoms, such as trouble with memory and concentration. To help combat these problems, researchers are trying to find out how long a person should take antibiotics for the various symptoms that may follow a bout with Lyme disease. Individuals who have previously had Lyme disease can be infected again if bitten by an infected tick.
Two types of blacklegged ticks, which look quite similar, are largely responsible for transmitting Lyme disease in the United States:
The best way to prevent Lyme disease is to avoid contact with deer ticks, especially during the summer months when infections are most common. Other useful tips:
Research supported by the National Institutes of Health and CDC suggest that a tick must be attached to the body for at least 36 hours to transmit Lyme disease. Risk of infection can be decreased by promptly removing ticks. After finding a tick, remove it using fine-tipped tweezers; do not use petroleum jelly, a hot match, nail polish or other products. Grab the tick close to the skin and pull up gently so that all parts of the tick are removed. Wash hands afterward with soap and water or waterless alcohol-based hand rub, and clean the area with an antiseptic, such as rubbing alcohol, or soap and water. Place the tick in a tightly closed container for examination by the local health department or healthcare provider.
For more information on how to prevent Lyme disease, visit CDC.
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Last Updated October 09, 2012