Lyme Disease, The
Facts, The Challenge
Introduction
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 present.
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)
Early Infection
* Rash (erythema migrans)
* Muscle and joint
aches
* Headache
* Stiff neck
*
Significant fatigue
* Fever
* Facial
paralysis (Bell's palsy)
* Meningitis
* Brief
episodes of joint pain and swelling
Less common:
* Eye problems such as conjunctivitis
* Heart
abnormalities such as heart block and myocarditis
Late Infection
* Arthritis, intermittent or chronic
Less Common:
* 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 members.
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
recovery.
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 the joints.
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 antibiotic therapy.
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 bacterium.
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 DEET.
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
disease.
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 clothing.
* Inspect the body thoroughly and remove carefully any
attached ticks.
* 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 bacterial infection.
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, Maryland 20892.
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 the
bacterium.
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