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Lyme Disease, The Facts, The Challenge
In the early 1970s, a mysterious clustering of arthritis occurred among
children in Lyme, Connecticut, and surrounding towns. Medical
researchers soon recognized the illness as a distinct disease, which
they called Lyme disease. They subsequently described the clinical
features of Lyme disease, established the usefulness of antibiotic
therapy in its treatment, identified the deer tick as the key to its
spread, and isolated the bacterium that caused it.
Lyme disease is still mistaken for other ailments, and it continues to
pose many other challenges: it can be difficult to diagnose because of
the inadequacies of today's laboratory tests; it can be troublesome to
treat in its later phases; and its prevention through the development of
an effective vaccine is hampered by the elusive nature of the bacterium.
The National Institutes of Health (NIH), a part of the U.S. Public
Health Service, conducts and supports biomedical research aimed at
meeting the challenges of Lyme disease. This brochure presents the most
recently available information on the diagnosis, treatment, and
prevention of Lyme disease.
How Lyme Disease Became Known
Lyme disease was first recognized in 1975 after researchers investigated
why unusually large numbers of children were being diagnosed with
juvenile rheumatoid arthritis in Lyme and two neighboring towns. The
investigators discovered that most of the affected children lived near
wooded areas likely to harbor ticks. They also found that the children's
first symptoms typically started in the summer months coinciding with
the height of the tick season. Several of the patients interviewed
reported having a skin rash just before developing their arthritis, and
many also recalled being bitten by a tick at the rash site.
Further investigations resulted in the discovery that tiny deer ticks
infected with a spiral-shaped bacterium or spirochete (which was later
named Borrelia burgdorferi) were responsible for the outbreak of
arthritis in Lyme.
Ticks that Most Commonly Transmit B. burgdorferi in the U.S. (These
ticks are all quite similar in appearance.)
Ixodes dammini--most common in the northeast and midwest
Ixodes scapularis--found in south and southeast
Ixodes pacificus--found on the west coast
In Europe, a skin rash similar to that of Lyme disease had been
described in medical literature dating back to the turn of the century.
Lyme disease may have spread from Europe to the United States in the
early 1900s but only recently became common enough to be detected.
The ticks most commonly infected with B. burgdorferi usually feed and
mate on deer during part of their life cycle. The recent resurgence of
the deer population in the northeast and the influx of suburban
developments into rural areas where deer ticks are commonly found have
probably contributed to the disease's rising prevalence.
The number of reported cases of Lyme disease, as well as the number of
geographic areas in which it is found, has been increasing. Lyme disease
has been reported in nearly all states in this country, although most
cases are concentrated in the coastal northeast, mid-Atlantic states,
Wisconsin and Minnesota, and northern California. Lyme disease is
endemic in large areas of Asia and Europe. Recent reports suggest that
it is present in South America, too.
Symptoms of Lyme Disease
Erythema Migrans. In most people, the first symptom of Lyme disease is
a red rash known as erythema migrans (EM). The telltale rash starts as a
small red spot that expands over a period of days or weeks, forming a
circular, triangular, or oval-shaped rash. Sometimes the rash resembles
a bull's eye because it appears as a red ring surrounding a central
clear area. The rash, which can range in size from that of a dime to the
entire width of a person's back, appears within a few weeks of a tick
bite and usually occurs at the site of a bite. As infection spreads,
several rashes can appear at different sites on the body.
Erythema migrans is often accompanied by symptoms such as fever,
headache, stiff neck, body aches, and fatigue. Although these flu-like
symptoms may resemble those of common viral infections, Lyme disease
symptoms tend to persist or may occur intermittently.
Arthritis. After several months of being infected by B. burgdorferi,
slightly more than half of those people not treated with antibiotics
develop recurrent attacks of painful and swollen joints that last a few
days to a few months. The arthritis can shift from one joint to another;
the knee is most commonly affected. About 10 to 20 percent of untreated
patients will go on to develop chronic arthritis.
Neurological Symptoms. Lyme disease can also affect the nervous system,
causing symptoms such as stiff neck and severe headache (meningitis),
temporary paralysis of facial muscles (Bell's palsy), numbness, pain or
weakness in the limbs, or poor motor coordination. More subtle changes
such as memory loss, difficulty with concentration, and a change in mood
or sleeping habits have also been associated with Lyme disease.
Nervous system abnormalities usually develop several weeks, months, or
even years following an untreated infection. These symptoms often last
for weeks or months and may recur.
Heart Problems. Fewer than one out of ten Lyme disease patients develops
heart problems, such as an irregular heartbeat, which can be signalled
by dizziness or shortness of breath. These symptoms rarely last more
than a few days or weeks. Such heart abnormalities generally surface
several weeks after infection.
Other Symptoms. Less commonly, Lyme disease can result in eye
inflammation, hepatitis, and severe fatigue, although none of these
problems is likely to appear without other Lyme disease symptoms being
How Lyme Disease Is Diagnosed
Lyme disease may be difficult to diagnose because many of its symptoms
mimic those of other disorders. In addition, the only distinctive
hallmark unique to Lyme disease--the erythema migrans rash--is absent in
at least one-fourth of the people who become infected. Although a tick
bite is an important clue for diagnosis, many patients cannot recall
having been bitten recently by a tick. This is not surprising because
the tick is tiny, and a tick bite is usually painless.
When a patient with possible Lyme disease symptoms does not develop the
distinctive rash, a physician will rely on a detailed medical history
and a careful physical examination for essential clues to diagnosis,
with laboratory tests playing a supportive role.
Most Common Symptoms of Lyme Disease (One or more may be present at
different times during infection)
* Rash (erythema migrans)
* Muscle and joint aches
* Stiff neck
* Significant fatigue
* Facial paralysis (Bell's palsy)
* Brief episodes of joint pain and swelling
* Eye problems such as conjunctivitis
* Heart abnormalities such as heart block and myocarditis
* Arthritis, intermittent or chronic
* Neurological conditions such as encephalitis or confusion
* Skin disorders
Blood Tests. Unfortunately, the Lyme disease microbe itself is difficult
to isolate or culture from body tissues or fluids. Most physicians look
for evidence of antibodies against B. burgdorferi in the blood to
confirm the bacterium's role as the cause of a patient's symptoms.
Antibodies are molecules or small substances tailor-made by the immune
system to lock onto and destroy specific microbial invaders.
Some patients experiencing nervous system symptoms may also undergo a
spinal tap. Through this procedure doctors can detect brain and spinal
cord inflammation and can look for antibodies in the spinal fluid.
The inadequacies of the currently available antibody tests may prevent
them from firmly establishing whether the Lyme disease bacterium is
causing a patient's symptoms. In the first few weeks following
infection, antibody tests are not reliable because a patient's immune
system has not produced enough antibodies to be detected. Antibiotics
given to a patient early during infection may also prevent antibodies
from reaching detectable levels, even though the Lyme disease bacterium
is the cause of the patient's symptoms.
Because some tests cannot distinguish Lyme disease antibodies from
antibodies to similar organisms, patients may test positive for Lyme
disease when their symptoms actually stem from other bacterial
infections. A lack of standardization of antibody tests and poor quality
control also contribute to inaccuracies in test results.
Due to these pitfalls, physicians must rely on their clinical judgement
in diagnosing someone with Lyme disease even though the patient does not
have the distinctive erythema migrans rash. Such a diagnosis would be
based on the history of a tick bite, the patient's symptoms, a thorough
ruling out of other diseases that might cause those symptoms, and other
implicating evidence. This evidence could include such factors as an
initial appearance of symptoms during the summer months when tick bites
are most likely to occur, outdoor exposure in an area where Lyme disease
is common, and a clustering of Lyme disease symptoms among family
New Tests Under Development. To improve the accuracy of Lyme disease
diagnosis, NIH-supported researchers are developing a number of new
tests that promise to be more reliable than currently available
procedures. Some of these detect distinctive protein fragments of the
Lyme disease bacterium in fluid samples.
NIH scientists are developing tests that use the highly sensitive
genetic engineering technique, known as polymerase chain reaction (PCR),
to detect extremely small quantities of the genetic material of the Lyme
disease bacterium in body tissues and fluids.
Several new methods to detect infection are under development in NIH
laboratories. Scientists have isolated a protein of B. burgdorferi,
called p39, that reacts strongly on blood tests. The presence of
antibodies to this protein was found to be a strong indicator of the
presence of B. burgdorferi. Although further research will be needed to
determine how soon after infection it can detect the bacterium, p39 may
prove to be an ideal test for Lyme disease.
A somewhat different approach is the use of an assay based on two
closely related spirochetal proteins that are not found in other species
of bacterial spirochetes. This assay differs from blood tests now in use
because it detects products of the spirochete itself rather than
detecting human antibodies to the bacterium.
How Lyme Disease Is Treated
Nearly all Lyme disease patients can be effectively treated with an
appropriate course of antibiotic therapy. In general, the sooner such
therapy is begun following infection, the quicker and more complete the
Antibiotics, such as doxycycline or amoxicillin taken orally for a few
weeks, can speed the healing of the erythema migrans rash and usually
prevent subsequent symptoms such as arthritis or neurological problems.
Patients younger than 9 years or pregnant or lactating women with Lyme
disease are treated with amoxicillin or penicillin because doxycycline
can stain the permanent teeth developing in young children or unborn
babies. Patients allergic to penicillin are given erythromycin.
Lyme disease patients with neurological symptoms are usually treated
with the antibiotic ceftriaxone given intravenously once a day for a
month or less. Most patients experience full recovery.
Lyme arthritis may be treated with oral antibiotics. Patients with
severe arthritis may be treated with ceftriaxone or penicillin given
intravenously. To ease these patients' discomfort and further their
healing, the physician might also give anti-inflammatory drugs, draw
fluid from affected joints, or surgically remove the inflamed lining of
Lyme arthritis resolves in most patients within a few weeks or months
following antibiotic therapy, although it can take years to disappear
completely in some people. Some Lyme disease patients who are untreated
for several years may be cured of their arthritis with the proper
antibiotic regimen. If the disease has persisted long enough, however,
it may irreversibly damage the structure of the joints.
Physicians prefer to treat Lyme disease patients experiencing heart
symptoms with antibiotics such as ceftriaxone or penicillin given
intravenously for about 2 weeks. If these symptoms persist or are severe
enough, patients may also be treated with corticosteroids or given a
temporary internal cardiac pacemaker. People with Lyme disease rarely
experience long-term heart damage.
Following treatment for Lyme disease, some people still have persistent
fatigue and achiness. This general malaise can take months to subside,
although it generally does so spontaneously without requiring additional
Researchers are currently conducting studies to assess the optimal
duration of antibiotic therapy for the various manifestations of Lyme
disease. Investigators are also testing newly developed antibiotics for
their effectiveness in countering the Lyme disease bacterium.
Unfortunately, a bout with Lyme disease is no guarantee that the illness
will be prevented in the future. The disease can strike more than once
in the same individual if he or she is reinfected with the Lyme disease
Lyme Disease Prevention
Avoidance of Ticks. At present, the best way to avoid Lyme disease is to
avoid deer ticks. Although generally only about one percent of all deer
ticks are infected with the Lyme disease bacterium, in some areas more
than half of them harbor the microbe.
Most people with Lyme disease become infected during the summer, when
immature ticks are most prevalent. Except in warm climates, few people
are bitten by deer ticks during winter months.
Deer ticks are most often found in wooded areas and nearby grasslands,
and are especially common where the two areas merge. Because the adult
ticks feed on deer, areas where deer are frequently seen are likely to
harbor sizable numbers of deer ticks.
To help prevent tick bites, people entering tick-infested areas should
walk in the center of trails to avoid picking up ticks from overhanging
grass and brush.
To minimize skin exposure to both ticks and insect repellents, people
outdoors in tick-infested areas should wear long pants and long-sleeved
shirts that fit tightly at the ankles and wrists. As a further
safeguard, people should wear a hat, tuck pant legs into socks, and wear
shoes that leave no part of the feet exposed. To make it easy to detect
ticks, people should wear light-colored clothing.
To repel ticks, people can spray their clothing with the insecticide
permethrin, which is commonly found in lawn and garden stores. Insect
repellents that contain a chemical called DEET (N,N-diethyl-M-toluamide)
can also be applied to clothing or directly onto skin. Although highly
effective, these repellents can cause some serious side effects,
particularly when high concentrations are used repeatedly on the skin.
Infants and children may be especially at risk for adverse reactions to
Pregnant women should be especially careful to avoid ticks in Lyme
disease areas because the infection can be transferred to the unborn
child. Such a prenatal infection can make the woman more likely to
miscarry or deliver a stillborn baby.
Checking for Ticks. Once indoors, people should check themselves and
their children for ticks, particularly in the hairy regions of the body.
The immature deer ticks that are most likely to cause Lyme disease are
only about the size of a poppy seed, so they are easily mistaken for a
freckle or a speck of dirt. All clothing should be washed. Pets should
be checked for ticks before entering the house, because they, too, can
develop symptoms of Lyme disease. In addition, a pet can carry ticks
into the house. These ticks could fall off without biting the animal and
subsequently attach to and bite people inside the house.
If a tick is discovered attached to the skin, it should be pulled out
gently with tweezers, taking care not to squeeze the tick's body. An
antiseptic should then be applied to the bite. Studies by NIH-supported
researchers suggest that a tick must be attached for many hours to
transmit the Lyme disease bacterium, so prompt tick removal could
prevent the disease.
The risk of developing Lyme disease from a tick bite is small, even in
heavily infested areas, and most physicians prefer not to treat patients
bitten by ticks with antibiotics unless they develop symptoms of Lyme
Vaccine Development. Because Lyme disease is difficult to diagnose and
sometimes does not respond to treatment, researchers are trying to
create a vaccine that will protect people from the disorder. Vaccines
work in part by prompting the body to generate antibodies. These
custom-shaped molecules lock onto specific proteins made by a virus or
bacterium--often those proteins lodged in the microbe's outer coat. Once
antibodies attach to an invading microbe, other immune defenses are
evoked to destroy it.
Tips for Personal Protection
* Avoid tick-infested areas, especially in May, June, and July.*
* Wear light-colored clothing so that ticks can be easily spotted.
* Wear long-sleeved shirts and closed shoes and socks.
* Tuck pant legs into socks or boots and tuck shirt into pants
* Apply insect repellant containing permethrin to pants, socks, and
shoes, and compounds containing DEET on exposed skin. Do not
overuse these products.
* Walk in the center of trails to avoid overgrown grass and brush.
* After being outdoors in a tick-infested area, remove, wash, and dry
* Inspect the body thoroughly and remove carefully any attached
* Check pets for ticks.
* Local health departments and park or agricultural extension services
may have information on the seasonal and geographical distribution of
ticks in your area.
How to Remove a Tick
* Tug gently but firmly with blunt tweezers near the "head" of the
tick until it releases its hold on the skin.
* To lessen the chance of contact with the bacterium, try not to
crush the tick's body or handle the tick with bare fingers.
* Swab the bite area thoroughly with an antiseptic to prevent
Development of an effective vaccine for Lyme disease has been difficult
to create for a number of reasons. Scientists need to find out how the
immune system protects against the bacterium because people who have
been infected once can acquire the infection again. In addition, there
are several different strains of the bacterium, each with its own
distinct set of proteins, and bacteria within an individual strain may
change the shape of their proteins over time so that antibodies can no
longer identify and lock onto them.
Tick Eradication. In the meantime, researchers are trying to develop an
effective strategy for ridding areas of deer ticks. Studies show that a
single fall spraying of pesticide in wooded areas can substantially
reduce the number of adult deer ticks residing there for as long as a
year. Spraying on a large scale, however, may not be economically
feasible and may prompt environmental or health concerns.
Scientists are also pursuing biological control of deer ticks by
introducing tiny stingerless wasps, which feed on immature ticks, into
tick-infested areas. Researchers are currently assessing the
effectiveness of this technique.
Successful control of deer ticks will probably depend on a combination
of tactics. More studies are needed before wide-scale tick control
strategies can be implemented.
Research-The Key to Progress
Although Lyme disease poses many challenges, they are challenges the
medical research community is well equipped to meet. New information on
Lyme disease is accumulating at a rapid pace, thanks to the scientific
research being conducted around the world.
This brochure is not copyrighted and users are encouraged to reproduce
and distribute as many free copies as needed. Single copies and
black-and-white reproducible artwork are available by writing to: Lyme
Disease Booklet, NIAMS/NIH, Box AMS, 9000 Rockville Pike, Bethesda,
For more information about Lyme disease, you may want to contact your
State or local Department of Health (check the government listings in
your phone book). This agency may be able to tell you whether Lyme
disease is common in your area. Also, staff of the Department may
suggest nearby hospitals or clinics where you can be tested for Lyme
disease. They may also know local places where ticks can be tested for
Information provided by the NIH.