Lyme Disease

Also known as tick-borne borreliosis or Lyme arthritis, Lyme disease is caused by the bacteria Borrelia burgdorferi, which is transmitted by the Ixodes tick.  Lyme disease may cause symptoms affecting the skin, nervous system, heart and/or joints.  Lyme disease is most common in the Northeast and mid-Atlantic states.

Causes and Development; Contributing Risk Factors

Not all deer ticks are infected with the bacteria that causes Lyme disease.  Ticks can become infected if they feed on small animals that are infected.  The disease can be spread when a tick infected with the bacteria bites a person and stays attached for a period of time.  Person-to-person spread of Lyme disease does not occur.

Lyme disease can affect people of any age.  People who spend time in grassy and wooded environments are at an increased risk of exposure.  The chances of being bitten by a deer tick are greater during times of the year when ticks are most active.  Deer ticks in the nymphal stage are active from mid-May to mid-August, and are about the size of poppy seeds.  Adult ticks, which are approximately the size of sesame seeds, are most active in mid to late fall.  The risk of exposure to infected deer ticks may be statewide.

Signs and Symptoms

Early symptoms may develop within a week to a few months of the tick bite.  In about half of these cases a large, reddish rash about 2 inches in diameter appears and expands around or near the site of the bite.  Sometimes multiple rash sites appear.  Other symptoms, such as fever, headache, fatigue, stiff neck, muscle and/or joint pain, may develop.  If left untreated, within a few weeks to months, complications, such as meningitis, facial palsy, or heart abnormalities may occur.  Later symptoms may develop in people who did not have early symptoms or did not recognize them.  Swelling and pain in the large joints may recur over many years.  It is believed that re-infection is possible i.e. having it once does not provide full immunity.

Diagnosis and Tests

Laboratory testing for Lyme disease is under continuing development, but is still the best method to confirm the diagnosis.  The Lyme Disease Foundation (LDF), in their brochure entitled "LDF Frequently Asked Questions About Lyme Disease" (1999), lists nine reasons for false negative Lyme disease tests results.  This means that even though tests indicate you don't have the disease, you still could.

Nine reasons for false negative Lyme disease tests results:
A. Antibodies against Borrelia burgdorferi (Bb) are present, but the laboratory is unable to detect them.

B. Antibodies against Bb may not be present in detectable levels in patients with Lyme disease.  Possible reasons for this are listed below.

1. The patient is currently on, or has recently taken, antibiotics.  The antibacterial effect of antibiotics can reduce the body's production of antibodies.
2. The patient is currently on or has previously taken anti-inflammatory steroidal drugs (such as those taken to treat
   rheumatoid arthritis) or certain anticancer drugs.  These can suppress a person's immune system, thus reducing or preventing an antibody response.
3. The patient's antibodies may be bound with the bacteria with not enough free antibodies available for testing.  This reason is very important and prevalent.  Some of the worst cases of Lyme disease test negative – too much bacteria for the immune system to handle.
4. The patient could be immunosuppressed for a number of other reasons and the immune system is not reacting to the bacterium.
5. The bacterium has changed its makeup (antigenic shift) limiting recognition by the patient's immune system.
6. The patient's immune response has not been stimulated to produce antibodies, i.e., the blood test is taken too soon after the tick-bite (2-6 weeks).  Please do not interpret this statement as implying that you should wait for a positive test to begin treatment.
7. The laboratory has raised its cutoff so high that a patient's previously positive test is now borderline or negative.
8. The patient is reacting to the Lyme bacterium, but is not producing the "right" bands to be considered positive.

Treatment and Prevention

What can be done to prevent it? When in tick-infested areas (i.e. tall grass, overgrown brush, etc.), special precautions should be taken.  Wear light-colored clothing, tuck pants legs into socks, and wear closed toe shoes.  Use commercial insect repellents (particularly those containing DEET) sparingly and with care, as they may cause side-effects, especially in young children.  Avoid application to damaged skin.  When returning from outdoors it is important to check yourself, your children and your pets for ticks.  Look for ticks in all joint areas, the navel, behind ears, in the hairline, and in other skin folds.  Wash all skin treated with insect repellent thoroughly.  Keep your lawn mowed and cut overgrown brush.

Prognosis

Prognosis is improved with prompt diagnosis and appropriate, early treatment.