Lyme Disease

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Institutes of Health

National Institute of Allergy and Infectious Diseases

National Institute of Arthritis and Musculoskeletal and Skin Diseases

THE FACTS THE CHALLENGE 

Lyme Disease


THE F ACTS THE CHALLENGE 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

National Institutes of Health 

National Institute of Allergy and Infectious Diseases 

National Institute of Arthritis and Musculoskeletal and Skin Diseases 

NIH Publication No. 03-7045 

April 2003 

www.niaid.nih.gov 
Contents


Introduction 1


How Lyme Disease Became Known 3


Symptoms of Lyme Disease 6


How Lyme Disease Is Diagnosed 9


How Lyme Disease Is Treated 13


Lyme Disease Prevention 16


Research: The Key to Progress 21


Glossary 23


More Information 25


Photo Descriptions & Credits 27

Introduction


In the early 1970s, a mysterious clustering of arthritis

cases occurred among children in Lyme, Connecticut,

and surrounding towns. Medical experts soon recognized

the illness as a distinct disease, which they called Lyme

disease. They subsequently described the signs and 

symptoms of Lyme disease, established the usefulness

of antibiotics for treating it, 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, including

the following:

• It can be difficult to diagnose

• It can be troublesome to treat in its later phases.

• A number of different ticks can transmit diseases with

symptoms similar to Lyme disease. 

• Deer ticks can transmit diseases other than 

Lyme disease. 

This brochure presents the most recently available 

information on the diagnosis, treatment, and prevention 

of Lyme disease. 

Note: Words in bold are in the glossary at the end of this booklet. 

1

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, Connecticut, and two neighboring 

towns. The researchers discovered that most of the 

affected children lived and played near wooded areas 

where ticks live. They also found that the children’s first 

symptoms typically started in the summer months, 

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 discovered 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 often transmit 

B. burgdorferi in the United States 

Ixodes scapularis–most common in the 

Northeast and Midwest. Also found in 

the South and Southeast. 

Ixodes pacificus–found on the west coast. 

(These ticks look quite similar.) 

3

In Europe, a skin rash similar to that of Lyme disease had 

been described in medical literature dating back to the 

turn of the 20th century. Lyme disease may have spread 

from Europe to the United States in the early 1900s, 

but health experts only recently recognized it as a 

distinct illness. 

Small rodents and deer play an important role in a deer 

tick’s life cycle. 

• Deer ticks lay eggs that turn into 

larvae that feed on mice and other 

small mammals. 

• The larvae then develop into immature 

ticks called nymphs. 

• The nymphs then feed on small mammals 

and humans. 

• Adult deer ticks usually feed on deer 

during the adult part of their life cycles. 

4

Both nymphs and adult ticks can transmit Lyme diseasecausing bacteria. The recent increase of the deer 

population in the Northeast and of housing developments 

in rural areas where deer ticks are commonly found 

probably contributed to the disease’s increased spread. 

The number of reported cases of Lyme disease as well 

as the number of geographic areas in which it is found 

have been increasing. Lyme disease has been reported in 

nearly all states in the United States, although more than 

98 percent of all reported cases are concentrated in the 

coastal Northeast, mid-Atlantic states, Wisconsin and 

Minnesota, and northern California. Lyme disease is 

also found in large areas of Asia and Europe. 

5

Symptoms of Lyme Disease 

Erythema Migrans 

Usually, the first symptom of Lyme disease is a red rash 

known as erythema migrans (EM). The telltale rash starts 

as a small red spot at the site of the tick bite. The spot 

expands over a period of days or weeks, forming a 

circular or oval-shaped rash. Sometimes the rash 

resembles a bull’s eye, appearing as a red ring 

surrounding a clear area with a red center. The rash, 

which can range in size from that of a dime to the width 

of a person’s back, appears within a few weeks of a tick 

bite and usually at the site of the bite. As infection 

spreads, 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 come and go. 

Arthritis


After several months of B. burgdorferi


infection, slightly more than half of


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 

6

another. The knee is most commonly affected. About 


10 to 20 percent of untreated people will go on to 


develop chronic (long-lasting) 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 

• Poor muscle movement 

More subtle changes such as memory loss, difficulty 

concentrating, and a change in mood or sleeping habits 

have also been associated with Lyme disease. 

Nervous system problems usually develop several 

weeks, months, or even years following an untreated 

infection. These symptoms often last for weeks or 

months and may return. 

7

Less commonly, untreated people may develop other 

problems weeks, months, or even years after infection. 

These include 

Heart Problems 

Fewer than 1 out of 10 people with Lyme disease 

develop heart problems, such as an irregular heartbeat, 

which can start with dizziness or shortness of breath. 

These symptoms rarely last more than a few days or 

weeks. Such heart problems generally show up several 

weeks after infection. 

Other Symptoms 

Less commonly, Lyme disease can result in eye 

inflammation, hepatitis (liver disease), and severe 

fatigue, although none of these problems is likely 

to appear without other Lyme disease symptoms 

being present. 

8

How Lyme Disease is Diagnosed 

Doctors or other health care workers may have difficulty 

diagnosing Lyme disease because many of its symptoms 

are similar to those of other disorders. In addition, the 

only distinctive sign unique to Lyme disease—the 

erythema migrans rash—is absent in at least one-fourth 

of the people who become infected. 

The results of recent research studies show that an 

infected tick must be attached to a person’s skin for at 

least 2 days to transmit Lyme bacteria. Although a tick 

bite is an important clue for diagnosis, many people 

cannot recall having been bitten recently by a tick. This 

is not surprising because the deer tick is tiny and a tick 

bite is usually painless. 

When a person with possible Lyme disease symptoms 

does not develop the distinctive rash, a doctor will rely 

on a detailed medical history and a careful physical 

examination for clues to diagnose it, with laboratory 

tests to support the diagnosis. 

9

Blood Tests


The Lyme disease bacterium is difficult to find in 


laboratory tests of body tissues or fluids. Therefore,


most health care providers look for evidence of 


antibodies against B. burgdorferi in the blood to 


confirm the bacterium’s role as the cause of symptoms. 


Some people with nervous system symptoms may also get


a spinal tap. Using this procedure, doctors can detect brain


and spinal cord inflammation and can look for antibodies


or genetic material of B. burgdorferi in the spinal fluid. 


Doctors cannot always firmly establish whether Lyme 


disease bacteria are causing symptoms. In the first few


weeks following infection, antibody tests are not reliable


because a person’s immune system has not produced


enough antibodies to be detected. Antibiotics given 


early during infection may also prevent antibodies from


reaching detectable levels, even though the Lyme disease


bacterium is the cause of symptoms.


The antibody test most often used is called an ELISA


(enzyme-linked immunosorbent assay) test. The U.S. Food


and Drug Administration has approved two antibody tests. 


• Prevue B, a rapid test, can give results within an hour. 

•	 The C6 Lyme Peptide ELISA is very sensitive 

and specific. 

10 
When an ELISA is positive, it should be confirmed with a 

second, more specific test called a Western blot. 

Doctors must rely on their clinical judgment in 

diagnosing someone with Lyme disease when the person 

does not have the distinctive EM rash. Such a diagnosis 

would be based on 

• Time of year 

• History of a tick bite 

• Symptoms 

•	 Thorough ruling out of other diseases that might cause 

those symptoms 

Doctors may consider such factors as the first appearance 

of symptoms during the summer months when tick bites 

are most likely to occur and outdoor exposure in an area 

where Lyme disease is common. 

11

New Tests Under Development


Health care providers need tests to distinguish between


people who have recovered from previous infection 


and those who continue to suffer from active infection. 


To improve the accuracy of Lyme disease diagnosis,


National Institutes of Health (NIH)-supported researchers


are re-evaluating existing tests and developing a number


of new tests that promise to be more reliable than 


currently available ones. 


NIH scientists are developing tests that use the highly


sensitive genetic engineering technique known as PCR


(polymerase chain reaction) as well as microarray 


technology to detect extremely small quantities of the


genetic material of the Lyme disease bacterium or its


products in body tissues and fluids.


A bacterial protein, outer surface protein (Osp) C,


is proving useful for the early detection of specific 


antibodies in people with Lyme disease. Since the


genome of B. burgdorferi has been sequenced, new


avenues are available for improving understanding of 


the disease and its diagnosis.


12

How Lyme Disease isTreated 

Using antibiotics appropriately, health care workers 


can effectively treat nearly anyone with Lyme disease. 


In general, the sooner treatment is begun following 


infection, the quicker and more complete the recovery.


Antibiotics such as doxycycline, cefuroxime axetil, or


amoxicillin, taken orally for a few weeks, can speed the


healing of the EM rash and usually prevent subsequent


symptoms such as arthritis or neurological problems.


Doxycycline will also effectively treat most other 


tickborne diseases.


When Lyme disease occurs in children younger than 


9 years, or in pregnant or breast-feeding women, they


are usually treated with amoxicillin, cefuroxime axetil,


or penicillin because doxycycline can stain the permanent


teeth developing in young children or unborn babies.


People allergic to penicillin are given erythromycin or


related drugs.


Arthritis


People with Lyme arthritis may be treated with oral


antibiotics. People with severe arthritis may be treated


with ceftriaxone or penicillin given intravenously. To


ease discomfort and to further healing, the doctor might


also give anti-inflammatory drugs, draw fluid from 


affected joints, or surgically remove the inflamed


lining of the joints.


13

Lyme arthritis goes away in most people within a few


weeks or months following antibiotic treatment. In some,


however, it can take years to disappear completely. Some


people with Lyme disease who are untreated for several 


years may be cured of their arthritis with the proper


antibiotic treatment. If the disease has persisted long


enough, however, it may permanently damage the 


structure of the joints.


Neurological Problems


Doctors usually treat people who have neurological


symptoms with the antibiotic ceftriaxone given 


intravenously once a day for a month or less. Most 


people recover completely.


Heart Problems


Doctors prefer to treat people with Lyme disease who


have heart symptoms with antibiotics such as ceftriaxone


or penicillin given intravenously for about 2 weeks. If


these symptoms persist or are severe enough, they may


also be given a temporary
internal cardiac pacemaker. 

People with Lyme disease
rarely have long-term heart damage.


14

Following treatment for Lyme disease, some people still 

have muscle achiness, neurological symptoms such as 

problems with memory and concentration, and fatigue. 

NIH-sponsored researchers are conducting studies to 

determine the cause of these symptoms and how to best 

treat them. Studies suggest that people who suffer from 

chronic Lyme disease may be genetically predisposed 

to develop an autoimmune response that contributes to 

their symptoms. Researchers are now examining the 

significance of this finding in great detail. 

Researchers are also currently conducting studies to find 

out the best length of time to give antibiotics for the 

various signs and symptoms of Lyme disease. 

Unfortunately, a bout with Lyme disease is no guarantee 

that the illness will not return. The disease can strike 

more than once in the same person if he or she is 

reinfected with Lyme disease bacteria. 

15

Lyme Disease Prevention 

Avoid Ticks


At present, the best way to avoid Lyme disease is to avoid


deer ticks. Although generally only about 1 percent of all


deer ticks are infected with Lyme disease bacteria, in


some areas more than half of them harbor the germs.


Most people with Lyme disease become infected during


the summer, when immature ticks are most prevalent. 


In warm climates, deer ticks thrive and bite during the


winter months.


Deer ticks are most often found in wooded areas and


nearby shady 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 large numbers of deer ticks. 


Pregnant women should be especially careful to avoid


ticks in Lyme disease areas because infection can be


transferred to an unborn child. Although rare, such a 


prenatal infection may make the woman more likely to


miscarry or deliver a stillborn baby.


16

• To help prevent contact with ticks, walk in the 

center of trails to avoid picking up ticks from 

overhanging grass and brush. 

• To minimize skin exposure to ticks, wear long 

pants and long-sleeved shirts that fit tightly at 

the ankles and wrists. As a further safeguard 

wear a hat, tuck pant legs into socks, and wear 

shoes that leave no part of the feet exposed. 

• To make it easy to find ticks on clothes, wear 

light-colored clothing. 

• To keep ticks away, spray clothing with the 

insecticide permethrin, commonly found in 

DEET (N, N-diethyl-M-toluamide). 

insect repellents that contain a chemical called 

lawn and garden stores. 

• To repel ticks, spray clothing or the skin with 

17

Although highly effective, these repellents can cause


some serious side effects, particularly when high 


concentrations are used repeatedly on the skin. Infants


and children especially may suffer from bad reactions 


to DEET. If you repeatedly apply insect repellants with


concentrations of DEET higher than 15 percent, you


should wash your skin with soap and water as well as 


any clothing.


Check for Ticks


The immature deer ticks 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. Once indoors


•	 Check for ticks, particularly in the hairy regions 

of the body. 

• Wash all clothing. 

• Check pets for ticks before letting them in the house. 

A pet can carry ticks into the house. These ticks could 

fall off without biting the animal and then attach to 

and bite people. In addition, pets can develop symptoms 

of Lyme disease. 

18

If a tick is attached to the skin 

•	 Pull it out gently with tweezers, taking care not to 

squeeze the tick’s body. 

• Apply an antiseptic to the bite. 

Studies by NIH-supported researchers suggest that a tick 

must be attached for at least 48 hours to transmit Lyme 

disease bacteria, so removing the tick promptly could 

keep you from getting infected. 

The risk of developing Lyme disease from a tick bite is 

small, even in heavily infested areas, and most doctors 

prefer not to use antibiotics to treat people bitten by ticks 

unless they develop symptoms of Lyme disease. 

Get Rid of Ticks


Deer provide a safe haven for ticks that transmit 


B. burgdorferi and other disease-causing microbes. 


You can reduce the number of ticks, which can 


spread diseases in your area, by clearing trees and


removing yard litter and excess brush that attract


deer and rodents.


19

In the meantime, researchers are trying to develop an 

effective strategy for ridding areas of deer ticks. Studies 

show that spraying pesticide in wooded areas in the 

spring and fall can substantially reduce for more than 

a year the number of adult deer ticks living there. 

Spraying on a large scale, however, may not be 

economically feasible and may prompt environmental 

or health concerns. 

Researchers are also testing pesticide-treated deer and 

rodent feeders, which may offer an environmentally safer 

alternative. One product, the Maxforce Tick Management 

System, tested by the U.S. Centers for Disease Control 

and Prevention, reduces the number of ticks in the 

landscape by 80 percent the first year and 97 percent 

by year two.

Successful control of deer ticks will probably depend on 

a combination of tactics. Before wide-scale tick control 

strategies can be put into practice, there need to be more 

definitive studies. 

20

Research: The Key to Progress 

The National Institutes of Health (NIH), a part of the 

U.S. Department of Health and Human Services (DHHS), 

conducts and supports biomedical research aimed at 

meeting the challenges 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 

getting infected. Vaccines work in part by prompting 

the body to make antibodies. These custom-shaped 

molecules lock onto specific proteins made by a virus 

or bacterium, often those proteins lodge in the microbe’s 

outer coat. Once antibodies attach to an invading 

microbe, other immune defenses are called upon to 

destroy it. 

Researchers are having difficulty developing an effective 

vaccine for Lyme disease for several reasons. Scientists 

need to find out how the immune system protects 

against the bacteria. The first vaccine based on the OspA 

of the Lyme bacterium is no longer in use. Scientists, 

however, are evaluating other vaccine candidates. Two 

of these, also based on OspA, show promise in clinical 

trials, to date. 

21

Scientists are gaining a better understanding of the 

human immune response that leads to Lyme disease. For 

example, researchers are uncovering the mechanisms 

responsible for treatment-resistant Lyme arthritis. 

Improved understanding of the human immune response 

may lead to better diagnostic and prognostic tools. For 

example, the B. burgdorferi immune complex assay, 

a test under development, indicates active Lyme disease 

infection earlier than antibody tests now in use. 

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. 

22

Glossary 

antibodies–molecules tailor-made by the immune system 

to lock onto and destroy specific germs. 

autoimmune–when the immune system mistakenly 

attacks the body’s own organs and tissues. 

genes–units of genetic material that carry the directions 

a cell uses to perform a specific function. 

genetic predisposition–when a person has alterations in 

the genes of their cells that increase his/her risk of 

developing the disease. 

genome–the sum of all the genetic material in 

any organism. 

immune defenses–a bodywide network of cells and 

organs that has evolved to defend the body against 

attacks by disease-causing germs. 

immune response–the reaction of the immune system to 

foreign substances. 

immune system–a complex network of specialized cells, 

tissues, and organs that defends the body against attacks 

by disease-causing germs. 

23

microbe–the smallest forms of life, including bacteria, 

viruses, fungi, and parasites. 

molecules–the building blocks of a cell. Some examples 

are proteins, fats, and carbohydrates. 

prognostic–having the ability to predict or forecast the 

outcome (prognosis) of a disease. 

sequence–to determine the precise order of the four 

chemical parts of a gene—adenine, cystosine, guanine, 

and thymine. 

tissues–groups of similar cells joined to perform the 

same function. 

24

More Information


You can get more in-depth information on Lyme disease 

from your local library or a health care provider. Other 

sources of information include 

National Institute of Allergy and 


Infectious Diseases


National Institutes of Health


31 Center Drive, MSC 2520 

Bethesda, Maryland 20892-2520 

301-496-5717 

http://www.niaid.nih.gov 

National Institute of Arthritis and 

Musculoskeletal and Skin Diseases 

Information Clearinghouse 

National Institutes of Health 

1 AMS Circle


Bethesda, Maryland 20892-3675


1-877-22-NIAMS (1-877-226-4267)


301-495-4484


http://www.niams.nih.gov 

25

National Institute of Neurological Disorders and Stroke 

National Institutes of Health 

P.O. Box 5801


Bethesda, Maryland 20892


1-800-352-9424


301-496-5751


http://www.ninds.nih.gov 

National Library of Medicine


Medlineplus


8600 Rockville Pike


Bethesda, Maryland 20894


301-496-6308


http://medlineplus.gov 

U.S. Centers for Disease Control and Prevention 

1600 Clifton Road 

Atlanta, Georgia 30333 

1-800-311-3435 

http://www.cdc.gov 

U.S. Food and Drug Administration 

1-888-INFO FDA (1-888-463-6332) 

http://www.fda.gov 

26

Photo Descriptions & Credits


Front cover—Old growth cedar and ferns. 

Stockphoto: Photodisc/Getty Images 

Inside front cover—Borrelia burgdorferi, the bacteria 

that cause Lyme disease. National Institute of Allergy 

and Infectious Diseases 

P. 3—Ixodes scapularis (enlarged), most common 

tick vector in the Northeastern and Midwestern 

United States. Dr. Willy Burgdorfer, National Institute 

of Allergy and Infectious Diseases 

P. 4—Scientist holding mouse. Stockphoto: 

Photodisc/Getty Images 

P. 6 (Top)—Erythema migrans rash on an arm. 

National Institute of Allergy and Infectious Diseases 

P. 6 (Bottom)—Swollen knees due to Lyme arthritis. 

Courtesy of Dr. Alan Steere, Massachusetts General 

Hospital, Boston 

P. 10—Chemist performing a scientific experiment. 

Stock photo: Photodisc/Getty Images 

P. 19—Deer are common carriers of ticks which can 

transmit Lyme disease to humans and animals. 

National Institute of Allergy and Infectious Diseases 

Inside back cover—Microscopic image of Borrelia 

burgdorferi. Stock photo: Photodisc/Getty Images 

27

Notes


U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

National Institutes of Health 

National Institute of Allergy and Infectious Diseases 

National Institute of Arthritis and Musculoskeletal and Skin Diseases 

NIH Publication No. 03-7045 

April 2003 

www.niaid.nih.gov