Lyme Disease 

THE FACTS 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 
ii
Lyme Disease
 

THE FACTS 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. 08-7045 

July 2008 

www.niaid.nih.gov 
Contents
 

Introduction 1
 

How Lyme Disease Became Known 2
 

Symptoms of Lyme Disease 5
 

How Lyme Disease Is Diagnosed 8
 

How Lyme Disease Is Treated 11
 

How Lyme Disease Is Prevented 14
 

Research: The Key to Progress 18
 

Glossary 19
 

More Information 21
 

Photo Descriptions and Credits 23
 
Introduction
 

In the early 1970s, a mysterious clustering of arthritis 

cases occurred among children in Lyme, Connecticut, 

and surrounding towns. Puzzled medical experts 

eventually labeled the illness as a new disease, which 

they called Lyme disease. By the mid-1970s, scientists 

were busy describing signs and symptoms of Lyme 

disease to help doctors diagnose patients. Scientists 

eventually learned that antibiotics were an effective 

treatment, and that the bite of the deer tick was the 

key to the spread of disease. 

None of these findings, however, happened overnight. 

In fact, it wasn’t until 1981—through a bit of puzzle 

solving and keen recollection—that the cause of Lyme 

disease was identified and the connection between the 

deer tick and the disease was discovered. 

Lyme disease is still mistaken for other illnesses, and it 

continues to pose many other challenges, including the 

following: 

• It can be difficult to diagnose. 

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

• A number of different ticks can transmit diseases with 

symptoms like Lyme disease. 

• Deer ticks can pass on diseases other than Lyme disease. 

This booklet presents the most recently available 

information on the diagnosis, treatment, and prevention 

of Lyme disease. 

Note: Words in bold are defined in the glossary near the end of 

this booklet. 

1 
How Lyme Disease Became Known 

Lyme disease was first recognized in 1975 after 

researchers tried to find out why unusually large numbers 

of children were being diagnosed with juvenile rheumatoid 

arthritis in Lyme, Connecticut, and two neighboring towns. 

After considering several possible causes, such as contact 

with germs (microbes) in water or air, researchers focused 

their attention on deer ticks. They realized that most of 

the affected children lived and played near wooded areas. 

Researchers knew that the children’s first symptoms 

typically started during summer—the height of tick season. 

Several of the children reported having a skin rash just 

before developing their arthritis. Many of them recalled 

being bitten by a tick where the rash appeared. 

Before Lyme Disease Became Known 

Around the same time, about 2,500 miles away from 

Lyme, Willy Burgdorfer, Ph.D., was conducting research 

at Rocky Mountain Laboratories (RML) in Hamilton, 

Montana, part of the National Institute of Allergy and 

Ticks that most often transmit B. burgdorferi in 

the United States: 

Isodes scapularis—most common in the Northeast 

and Midwest. Also found in the South and 

Southeast. 

Ixodes pacificus—found on the West Coast. 

These two ticks look quite similar. 

2 
Infectious Diseases (NIAID). Dr. Burgdorfer was 

studying Rocky Mountain spotted fever, which is also 

caused by the bite of a tick. 

In the summer of 1977, Allen C. Steere, M.D., was 

investigating the Lyme disease cases for the Yale 

University School of Medicine in Hartford, Connecticut. 

During conversations with Dr. Burgdorfer, Dr. Steere 

mentioned the deer tick as the likely carrier for Lyme 

disease. 

Researchers in Europe had written about a skin rash 

similar to that of Lyme disease in medical literature 

dating back to the turn of the 20th century. Dr. Burgdorfer 

wondered if the European rash, called erythema migrans, 

and Lyme disease might have the same cause. 

As Dr. Burgdorfer and his RML colleague Alan Barbour, 

M.D., continued to study spiral-shaped bacteria, or 

spirochetes, from infected deer ticks, they eventually 

achieved success. In late November 1981, the scientists 

found the cause of both Lyme disease and the European 

skin rash. The spirochete was later named Borrelia 

burgdorferi in honor of Dr. Burgdorfer for his role in 

discovering it. 

Although Lyme disease may have spread from Europe to 

the United States in the early 1900s, health experts only 

recently recognized it as a distinct illness. 

3 
Deer Ticks 

Small rodents and deer play an important role in a deer 

tick’s life cycle. Today, scientists who study Lyme disease 

are learning much more about that role. 

Both nymphs (immature ticks) and adult ticks can transmit 

Lyme disease-causing 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 have contributed to the spread of the disease. 

The numbers of cases of Lyme disease and of geographic 

areas in which it is found have increased. Healthcare 

providers have seen cases of Lyme disease in nearly 

all states in the United States. However, most reported 

cases are concentrated in the coastal Northeast, the 

mid-Atlantic states, Wisconsin, Minnesota, and northern 

California. Lyme disease is also found in large areas 

of Asia and Europe. 

• 	 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 
Symptoms of Lyme Disease
 

Erythema Migrans 

Erythema migrans (EM) is usually the first symptom of 

Lyme disease. 

• The telltale rash starts as a small red spot at the site 

of the tick bite. 

• The spot gets larger over a period of days or weeks 

and forms a red rash shaped like a circle or an oval. 

Sometimes the rash looks like 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 small coin to 

the width of your back, appears within a few weeks of a 

tick bite and usually at the place of the bite. As infection 

spreads, rashes can appear at different places on the body. 

Other symptoms that often appear with EM can include: 

• Fever 

• Headache 

• Stiff neck 

• Body aches 

• Tiredness 

Although these symptoms may be like those of common 

viral infections such as the flu, Lyme disease symptoms 

tend to continue longer or may come and go. 

5 
Arthritis 

After several months of infection with Lyme bacteria, 

slightly more than half of people not treated with antibiotics 

develop recurrent attacks of painful and swollen joints. 

These attacks last a few days to a few months. The arthritis 

can move from one joint to another. The knee is most 

commonly affected. 

About 10 to 20 percent of people who have not taken 

antibiotics will go on to develop chronic (long-lasting) 

arthritis. 

Neurological Symptoms 

Lyme disease can also affect your nervous system, causing 

symptoms such as the following: 

• Stiff neck and severe headache (meningitis) 

• Temporary paralysis of your facial muscles 

(Bell’s palsy) 

• Numbness, pain, or weakness in your limbs 

• Poor muscle movement 

Lyme disease can also cause more subtle changes such as 

• Memory loss 

• Difficulty with concentration 

• Change in mood or sleep habits 

6 
Neurological problems usually develop several weeks, 

months, or even years following untreated infection. 

These symptoms often last for weeks or months and 

may return. 

Less commonly, people who have not taken antibiotics 

may develop heart or other problems weeks, months, or 

even years after they were infected with Lyme bacteria. 

Heart Problems 

Fewer than 1 out of 10 people with Lyme disease develop 

heart problems, such as 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 a person 

is infected with Lyme bacteria. 

Other Symptoms 

Less commonly, Lyme disease can cause eye 

inflammation, hepatitis (liver disease), and severe fatigue. 

None of these problems, however, is likely to appear 

without other Lyme disease symptoms being present. 

7 
How Lyme Disease Is Diagnosed
 

Your healthcare provider may have difficulty diagnosing 

Lyme disease because many of its symptoms are similar to 

those of other illnesses. In addition, the only symptom that 

is unique to Lyme disease is the rash. That 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 the 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. 

If you have Lyme disease symptoms, but do not develop 

the distinctive rash, your healthcare provider will rely on 

a detailed medical history and a careful physical exam 

for clues to diagnose it. You will also be given laboratory 

tests to help diagnose the disease. 

Medical History 

If you don’t have the EM rash, your healthcare provider 

will diagnose Lyme disease based on 

• Whether your symptoms first appeared during the 

summer months when tick bites are most likely to occur 

• Whether you were outdoors in an area where Lyme 

disease is common 

• Whether you have been bitten by a tick 

• Whether you have other symptoms of Lyme disease 

In addition, your healthcare provider will rule out other 

diseases that might be causing your symptoms. 

8 
Lab Tests 

It is difficult for healthcare providers to find the 

bacterium that causes Lyme disease in lab tests of body 

tissues or fluids. Therefore, most look for evidence of 

antibodies against B. burgdorferi in the blood to confirm 

that the bacterium is causing the symptoms. 

Healthcare providers cannot always find out whether 

Lyme disease bacteria absolutely are causing symptoms. 

In the first few weeks following infection, antibody tests 

are not reliable because your immune system has not 

produced enough antibodies to be found. Antibiotics 

given early during infection may also prevent antibodies 

from reaching levels that a test can find, even though 

Lyme disease bacteria are causing your symptoms. 

The antibody test most often used is called an ELISA 

(enzyme-linked immunosorbent assay) test. The Food 

and Drug Administration (FDA) 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. 

If your ELISA is positive, your healthcare provider 

should confirm it with a second, more specific test called 

a Western blot. 

If you have nervous system symptoms, you may also 

get a spinal tap. Using this test, your healthcare provider 

9 
can find any inflammation in your brain and spinal 

cord and can look for antibodies or genetic material of 

B. burgdorferi in your spinal fluid. 

FDA has not approved tests for Lyme disease that use 

urine or some other body fluids to diagnose infection 

caused by Lyme bacteria. 

New Tests Being Developed 

Healthcare providers need tests to tell apart people who 

have recovered from previous Lyme infection and those 

who continue to suffer from active infection. 

To improve the accuracy of diagnosing Lyme disease, 

National Institutes of Health (NIH)-supported researchers 

are re-evaluating current tests. They are also developing a 

number of new tests that promise to be more reliable than 

those currently available. 

NIH-supported scientists are developing tests that use the 

highly sensitive genetic engineering technique known as 

PCR (polymerase chain reaction) as well as microarray 

and high-throughput genomic sequencing 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 detecting specific antibodies early in 

people with Lyme disease. Because researchers have 

determined the genome of B. burgdorferi, there are now 

new avenues for improving their understanding of the 

disease and its diagnosis. 

10 
How Lyme Disease Is Treated 

Using antibiotics appropriately, your healthcare provider 

can effectively treat your Lyme disease. In general, the 

sooner you begin treatment after you have been infected, 

the quicker and more complete your 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 symptoms 

such as arthritis or neurological problems. 

Doctors usually treat Lyme disease in children younger 

than 9 years, or in pregnant or breast-feeding women, with 

amoxicillin, cefuroxime axetil, or penicillin. They do not 

use doxycycline in these groups because the antibiotic can 

stain the permanent teeth developing in young children or 

unborn babies. 

Arthritis 

If you have Lyme arthritis, your healthcare provider may 

treat you with oral antibiotics. If your arthritis is severe, 

you may be given ceftriaxone or penicillin intravenously 

(through a vein). To ease any discomfort and to help with 

healing, your healthcare provider might also do one of 

the following: 

• Give you anti-inflammatory drugs 

• Draw fluid from your affected joints 

• Perform surgery to remove the inflamed lining of 

those joints 

In most people, Lyme arthritis goes away within a few 

weeks or months following antibiotic treatment. In some, 

however, it can take years to disappear completely. Some 

11 
people with Lyme disease who are untreated for several 

years may be cured of their arthritis with the proper 

antibiotic treatment. 

The disease, however, does not always go away with 

treatment. If it has lasted long enough, it may permanently 

damage the structure of your joints. 

Neurological Problems 

If you have neurological symptoms, your healthcare 

provider will probably treat you with the antibiotic 

ceftriaxone given intravenously once a day for a month 

or less. Most people recover completely. 

Heart Problems 

Healthcare providers prefer to treat people with Lyme 

disease who have heart symptoms with antibiotics such as 

ceftriaxone or penicillin given intravenously for about 

2 weeks. People with Lyme disease rarely have long-term 

heart damage. 

12 
Problems After Treatment 

Following treatment for Lyme disease, you might still 

have muscle aches, and neurological problems such as 

tiredness and trouble with memory and concentration. 

NIH-sponsored researchers are doing research to find 

out the cause of these symptoms and the best ways to treat 

them. Research studies suggest that people who suffer 

from post-Lyme disease symptoms may be genetically 

predisposed to develop an autoimmune response that 

contributes to their symptoms. Researchers are now 

examining the significance of this finding in greater detail. 

Researchers also are trying to find out the best length 

of time to give antibiotics for the various symptoms of 

Lyme disease. 

Unfortunately, having a bout with Lyme disease once is 

no guarantee that you will not get the illness again. It can 

strike more than once if you are reinfected with Lyme 

disease bacteria. 

13 
How Lyme Disease Is Prevented
 

Avoid Ticks 

At present, the best way you can 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 the ticks have the microbes. 

More people with Lyme disease become infected during 

the summer, when immature ticks are found most often. In 

warm climates, deer ticks thrive and bite during the winter 

months as well. 

• 	 Spray insect repellant with 20 to 30 percent 


DEET (a chemical) on exposed skin and 


clothing to prevent tick bites.
 

• 	 Spray clothing with permethrin, a repellant 


commonly found in lawn and garden stores. 


Permethrin kills ticks on contact. You should 


not apply permethrin directly to your skin.
 

• 	 Wear long pants, long sleeves, and long 

socks to keep ticks off your skin. Light-colored 

clothing will help you spot ticks more easily. 

Tucking pant legs into socks or boots and 

tucking shirts into pants help keep ticks on the 

outside of your clothing. If you’ll be outside for 

a long time, tape the area where your pants 

and socks meet to prevent ticks from crawling 

under your clothes. 

Source: Centers for Disease Control and Prevention, National 

Center for Zoonotic, Vector-Borne, and Enteric Diseases 

14 
Deer ticks are most often found in wooded areas and 

nearby shady grasslands, and are especially common 

where the two areas merge. Because adult ticks feed on 

deer, areas where deer are seen frequently are likely to 

have large numbers of deer ticks. 

If you are pregnant, be especially careful to avoid ticks in 

Lyme disease areas because you can pass on the infection 

to your unborn child. 

Repellants, although highly effective, can cause some 

serious side effects, particularly when you put high 

concentrations on your skin over and over again. Infants 

and children especially may suffer from bad reactions 

to insect repellants containing DEET. If you repeatedly 

apply such repellants with concentrations of DEET 

higher than 15 percent, you should wash your skin, and 

any clothing, with soap and water. 

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 

your body. 

• Wash all clothing. 

• Check pets for ticks before letting them inside. 

15 
Pets 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. 

Studies by NIH-supported researchers suggest that a 

tick must be attached to the body for at least 48 hours to 

transmit Lyme disease bacteria. Promptly removing the 

tick could keep you from getting infected. 

The risk of developing Lyme disease from a tick bite is 

small, even in heavily infested areas. Most healthcare 

providers prefer not to use antibiotics to treat people bitten 

by ticks unless they develop symptoms of Lyme disease. 

Remove a tick from your skin as soon as you 


notice it. Use fine-tipped tweezers to firmly 


grasp the tick very close to your skin. With a 


steady motion, pull the tick’s body away from 


your skin. Then clean your skin with soap and 


warm water. Throw the dead tick away with 


your household trash.
 

Avoid crushing the tick’s body. Do not be 


alarmed if the tick’s mouthparts remain in the 


skin. Once the mouthparts are removed from 


the rest of the tick, it can no longer transmit 


Lyme disease bacteria. If you accidentally 


crush the tick, clean your skin with soap and 


warm water or alcohol.
 

Don’t use petroleum jelly, a hot match, nail 


polish, or other products to remove a tick.
 

Source: Centers for Disease Control and Prevention, National 


Center for Zoonotic, Vector-Borne, and Enteric Diseases
 

16 
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.
 

In the meantime, researchers are trying to develop an 

effective strategy for ridding areas of deer ticks. 

Studies show that spraying pesticides 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 also are testing pesticide-treated deer 

and rodent feeders as a possibly safer alternative for 

the environment. Tests done by the Centers for Disease 

Control and Prevention suggest that at least one 

commercial product reduced the number of ticks in 

the landscape by 80 percent during the first year of use 

and 97 percent by the second year. 

Successful control of deer ticks will probably depend 

on a combination of tactics. Before strategies for 

wide-scale tick control can be put into practice, there 

needs to be more research. 

17 
Research: The Key to Progress
 

NIH conducts and supports biomedical research 

aimed at meeting the challenges of Lyme disease. Part 

of this research continues at NIAID’s Rocky Mountain 

Laboratories, where Dr. Burgdorfer performed his 

original work. 

Scientists are gaining a better understanding of the 

human immune response that leads to Lyme disease. 

For example, they are uncovering what causes treatmentresistant 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 being developed, shows 

active Lyme disease infection earlier than current 

antibody tests. 

Because Lyme disease is difficult to diagnose and may 

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 

system defenses are called upon to destroy it. 

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. 

18 
Glossary
 

antibody–a molecule 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 

gene–a unit of genetic material that carries the directions 

a cell uses to perform a specific function 

genetic predisposition–when a person has alterations 

in the genes of his or her cells which increase the risk of 

developing a disease 

genome–the sum of all the genetic materials in any 

organism 

high-throughput genomic sequencing–a biomedical 

process used to rapidly determine the order of nucleotides 

(parts of DNA and RNA) in multiple DNA samples. (DNA 

and RNA are molecules that contain genetic information.) 

immune response–the reaction of the immune system to 

foreign substances such as bacteria 

immune system–a complex network of specialized cells, 

tissues, and organs that defends the body against attacks by 

“foreign” invaders 

inflammation–a process of the immune system, with signs 

like redness and swelling, often seen at the site of an injury 

such as a tick bite 

19 
microarray–a tool used by scientists to analyze genomic 

information to understand how large numbers of genes are 

expressed or how they undergo changes to specific genetic 

sequences 

microbe–the smallest forms of life, including bacteria, 

viruses, fungi, and parasites 

molecule–a building block of a cell, such as proteins, fats, 

and carbohydrates 

prognostic–having the ability to predict or forecast the 

outcome (prognosis) of a disease 

tissue–a group of similar cells joined to perform the same 

function 

20 
More Information
 

You can get more in-depth information on Lyme disease 

from your local library or a healthcare provider. Other 

sources of information include 

National Institute of Allergy and Infectious Diseases 

National Institutes of Health 

6610 Rockledge Drive, MSC 6612 

Bethesda, MD 20892-6612 

866–284–4107 or 301–496–5717 

www.niaid.nih.gov 

National Institute of Arthritis and 

Musculoskeletal and Skin Diseases 

Information Clearinghouse 

National Institutes of Health 

1 AMS Circle 

Bethesda, MD 20892-3675 

877–22–NIAMS (877–226–4267) or 301–495–4484 

www.niams.nih.gov 

National Institute of Neurological Disorders and Stroke 

National Institutes of Health 

P.O. Box 5801 

Bethesda, MD 20824 

800–352–9424 or 301–496–5751 

www.ninds.nih.gov 

21 
National Library of Medicine 

MedlinePlus 

8600 Rockville Pike 

Bethesda, MD 20894 

888–FIND–NLM (888–346–3656) or 301–594–5983 

www.medlineplus.gov 

Centers for Disease Control and Prevention 

1600 Clifton Road 

Atlanta, GA 30333 

800–311–3435 or 404–639–3534 

www.cdc.gov 

Food and Drug Administration 

5600 Fishers Lane 

Rockville, MD 20857 

888–INFO–FDA (888–463–6332) 

www.fda.gov 

22 
Photo Descriptions and Credits
 

Front cover—Old growth cedar and ferns. 

Stockphoto: Photodisc/Getty Images 

Inside front and back covers—Borrelia burgdorferi, 

the bacteria that cause Lyme disease. National Institute 

of Allergy and Infectious Diseases 

Page 2—Ixodes scapularis (enlarged), most common tick 

vector in the Northeastern and Midwestern United States. 

Dr. Willy Burgdorfer, National Institute of Allergy and 

Infectious Diseases 

Page 4—Mouse. Stockphoto: Getty Images 

Page 5—Erythema migrans rash. National Institute of 

Allergy and Infectious Diseases 

Page 6—Swollen knees due to Lyme arthritis. Courtesy of 

Dr. Alan Steere, Massachusetts General Hospital, Boston 

Page 9—Chemist performing a scientific experiment. 

Stock photo: Photodisc/Getty Images 

Page 17—Deer are common carriers of ticks that can 

transmit Lyme disease to humans and animals. National 

Institute of Allergy and Infectious Diseases 

23 

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. 08-7045 

July 2008 

www.niaid.nih.gov