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Lyme Disease

Lyme disease was initially recognized in 1975, when a mysterious cluster of unusual illness developed in the Connecticut shoreline town of Lyme. This cluster of cases prompted a clinical and epidemiological investigation. A new disorder, Lyme disease, was described with a characteristic pattern of signs and symptoms. In 1982, Dr. Bergdorfer and his associates isolated a bacterium (named Borrelia burgdorferi, after its discoverer) in the gut of the tick Ixodes dammini. After intensive scientific investigation it was found that the infected tick passed the bacteria to whatever host it fed on (rabbit, mouse, deer, human, etc.). National surveillance began in 1982, and in 1998, over 16,000 cases were reported.

What causes Lyme disease

Lyme disease is caused by infection with the bacterium Borrelia burgdorferi. Lyme disease is transmitted to humans by infected ticks. Not all ticks will carry Lyme disease. The ticks that carry Lyme disease are the black-legged tick (or the deer tick) Ixodes scapularis (formerlyIxodes dammini), in the East, and the Western black-legged tick, Ixodes pacificus, in the West. These ticks have a life cycle that spans 2 years. They feed once during each stage of their life, the larval, the nymph, and the adult stages. Both the larval tick and the nymph tick prefer to feed on the white-footed mouse, the adult ticks prefer to feed on the white-tailed deer. It is the nymphs that are responsible for about 90% of Lyme disease transmission.

Ixodes ticks are much smaller than dog ticks. In the larval and nymphal stages, they are less than 2 mm in size, or the size of a pinhead. It is because of their small size that these tick bites go unnoticed in so many cases.

Lyme disease is most commonly seen in the spring and early summer when the nymphal ticks feed. The peak season is considered April to October. It is important to note that the tick needs to be attached for 36 to 48 hours before transmission of the bacterium occurs.

Lyme disease has been reported in 49 states and from more than 50 countries. In the U.S., most cases are seen in the following areas:

  • Southern New England to the Mid-Atlantic, from Massachusetts to Maryland
  • The North-central states, mainly Wisconsin and Minnesota
  • The West Coast, northern California, Nevada, Utah and Oregon

Lyme DiseasSymptoms 

There are 3 stages of Lyme disease:

  1. Early localized disease
  2. Early disseminated disease
  3. Late disease

Early localized disease 

is characterized by the development of a rash between 3 and 31 days after being bitten by a tick. This rash occurs in 80-90% of all cases and is called erythema migrans. The rash forms at the site of the bite and appears as an enlarging area of redness that may have a bull’s eye appearance or a solid-red appearance with vesicles at the center. The rash has an average diameter of 5 to 6 inches, but can be anywhere from 2 inches to 2 feet in diameter.  The rash may be warm to touch, and may burn or itch, but is usually asymptomatic. The rash usually occurs in the arm pits, the groin or on the legs, although it may occur anywhere on the body. If treatment is not given, the rash will last about 3 weeks. With treatment, it may disappear as soon as after a few days. Other symptoms may accompany the skin rash. These include malaise, fatigue, headache, stiff neck, joint and muscles aches, and low grade fever.

Early disseminated disease

This occurs between 3 and 10 weeks after the initial tick bite. This stage is characterized by:

  • multiple red rashes not at the site of the tick bite, and smaller than the initial rash
  • fever, muscle aches, headache, and malaise
  • aseptic meningitis (inflammation without infection)
  • enlarged lymph nodes
  • heart block (abnormal pulse)
  • changes in vision
  • tingling or numbness in hands and feet
  • facial nerve (cranial nerve VII) palsy (paralysis of the nerve manifesting as inability to close the eye on the involved side, loss of taste on the front portion of the tongue, drooping of the corner of the mouth on the affected side, and flattening of the muscles of the face on the affected side). Facial nerve palsy (similar to Bell’s palsy) may be the only manifestation of Lyme disease in children. It lasts 2 to 8 weeks and will usually resolve completely, although the course is not affected by treatment with antibiotics.

 

Late disease

This begins months to years after the initial infection and is manifested by arthritis. Arthritis is an inflammation of joints, with swelling and pain of the affected joint. The arthritis usually affects large joints, with the knee being the affected joint in over 90% of cases. If the disease is not treated at this stage, the arthritis will become recurrent. The episodes may increase in duration, lasting months in some cases. Late disease is also manifested by neurological disorders which are characterized by disorientation, confusion, memory loss, and concentration difficulties. These late disease neurological manifestations are rare in children.

According to the CDC, “Lyme disease acquired during pregnancy may lead to infection of the fetus and possibly to stillbirth, but adverse effects to the fetus have not been conclusively documented.”

Getting Diagnosis

Lyme disease can be difficult to diagnose for several reasons. Firstly, the symptoms can mimic many other diseases such as influenza, mononucleosis, and other viral illnesses. Secondly, the serologic (blood) testing done in commercial laboratories is not well standardized. Blood work should be sent to a reference laboratory whenever possible. These laboratories can be found by contacting the state health department.

Diagnosis should be made by looking at several factors:

  • A history of exposure to ticks, especially in high-risk areas
  • Signs and symptoms consistent with Lyme disease
  • Blood tests

It is important to note that a blood test may be used to support the diagnosis, but cannot be the only criteria used to make the diagnosis. The primary blood tests used to detect the bacterium, Borrelia burgdorferi,are antibody tests. These tests look for the presence of antibodies to the specific bacteria. Other tests used are called direct detection tests and include polymerase chain reaction (PCR) tests, culturing, and staining.

During the early stages of Lyme disease the diagnosis can be made clinically if the erythema migrans rash is present. It is not necessary nor appropriate to wait for blood tests to return before starting treatment when erythema migrans is present. In fact, the antibody cannot be detected until 3 to 6 weeks after initial infection. Therefore, a blood test performed before this time is very likely going to be negative.

Currently, a 2 test approach is recommended for blood detection of the bacterium Borrelia burgdorferi. The first test done is the enzyme immunoassay (EIA), which is used to detect the presence of antibodies against B. burgdorferi in the blood. If this test is positive, a confirmatory test called the Western immunoblot is performed. If the Western immunoblot test is also positive, and there is clinical evidence of Lyme disease, and you suspect recent exposure to a tick, then a diagnosis can be made. If the initial EIA test is negative, and it is early in the course of the illness, the EIA should be repeated in 3 to 6 weeks.

The polymerase chain reaction test (PCR) is a more sensitive and more specific test for identifying the presence of small quantities of bacterial DNA. The current recommendation is to interpret the results of a PCR test with caution, as it is still considered investigational for the diagnosis of Lyme disease.

Treatment of Lyme Disease

Early treatment of Lyme disease is important in preventing late manifestations of the disease. Early disease (erythema migrans rash) is treated with oral antibiotics for a course of 14 to 21 days. Information is limited regarding optimal duration of the antibiotic course. Preventive treatment with antibiotics of a tick bite alone, without any other symptoms, is not currently recommended.

Late disease is treated with either oral or intravenous antibiotics depending on the particular manifestation. The chart below delineates the current recommended treatment of Lyme disease in children.

 

 

 

Disease Category Drugs and Dose
Early localized disease
8 years and older Doxycycline, oral regimen, 100 mg twice a day for 14-21 days
All ages Amoxicillin, oral regimen, 25-50 mg/kg/day, divided into 2 doses (max 2 g/day) for 14-21 days
Early disseminated and late disease
Multiple erythema migrans Same as for early disease but for 21 days
Isolated facial palsy Same as for early disease but for 21-28 days
Arthritis Same as for early disease but for 28 days
Persistent or recurrent arthritis Ceftriaxone, 75-100 mg/kg, IV or IM, once a day (max 2 g/day) for 14-21 days; or penicillin, 300,000U/kg per day, IV, given in divided doses every 4 hours (max 20 million U/day) for 14-21 days
Carditis Ceftriaxone or penicillin–same as for persistent or recurrent arthritis
Meningitis or encephalitis Ceftriaxone or penicillin–same as for persistent or recurrent arthritis

For penicillin allergic patients, cefuroxime and erythromycin are alternative drugs.

IV=intravenous, IM=intramuscular

Corticosteroids should not be given for facial palsy.

Treatment for facial palsy will not affect the duration of the palsy, it is given to prevent late disease.

Persistent or recurrent arthritis is defined as evidence of arthritis for at least 2 months after treatment is initiated.

Taken from the 2000 Red Book: Report of the Committee on Infectious Diseases. 25th ed. Elk Grove

Village, IL: American Academy of Pediatrics; 2000:p.377.

Prevention

Prevention is the single most important factor in decreasing risk of infection. Deer ticks normally feed on the white-footed mouse, the white-tailed deer, and other mammals. Deer ticks like to hide in brush, overgrown fields, woods, tall grassy areas, and around old stone walls. They are most active when the temperature is 40 degrees F or greater. Deer ticks cannot fly or jump. They do not fall from tall tree branches. Ticks are picked up by direct contact when an animal or person brushes by tall grass or shrubs. Once a tick is on the skin, it will climb upward looking for a protected area of the body such as the back of the knee, the groin, or the armpit. If your family frequently hikes, camps, gardens, or someone in the family works outdoors, tick precautions are mandatory.

Personal precautions:

  • Wear light-colored clothing.
  • Tuck your pants into your socks and wear long-sleeved shirts.
  • Do not wear open toed sandals or shoes.
  • Tie back long hair.
  • Walk on the center of the trail, and avoid sitting directly in tall grassy areas or on stone walls.
  • Perform frequent “tick checks”–check your clothing and any exposed skin for ticks–remember that nymphal deer ticks are the size of a poppy seed!!
  • Use insect repellent–DEET(10% DEET for children) for the skin, and permethrin for clothing.
  • A whole-body, tick check at the end of the day (with particular attention to the groin area, under the arms, the scalp and behind the knees).
  • And remember to check your pets for ticks.

What you can do around your home:

  • Keep your lawn mowed frequently with attention to the edges of the yard.
  • Clear any brush away.
  • Stack woodpiles in a dry area.
  • Consider spraying of your yard with an insecticide beginning in April or May, with several sprayings (usually 2 to 4) ending in October or November. This should be done by a licensed company only.

Common Questions

1. Can my 6 year old get the new Lyme vaccine?

A Lyme disease vaccine was licensed by the FDA in December 1998, for people age 15 to 70 years. The CDC recommends use of the vaccine in high-risk individuals. High-risk individuals include people who engage in activities that result in frequent or prolonged exposure to areas that are tick-infested. The vaccine is not recommended for people who have no exposure or minimal exposure to infected ticks, or for people who reside in geographic areas of low risk.

The Lyme vaccine is given as a three shot series. The first dose is followed by a second dose 1 month later and then the third dose is given 12 months after the first dose. The vaccine is 80% effective (there is a 20% chance that one can get Lyme disease even after vaccination). Remember that no vaccine is 100% effective. It is generally well tolerated. The most common side effects reported are muscle aches, injection site pain, joint aches, joint swelling, headache, chills (with or without fever), and tremor.

A pediatric trial of the vaccine has just been completed (spring 2000). The trial results indicate that the vaccine is safe and effective for children age 4 years and older. In addition, the trials found that children age 4 to 14 years developed the same level of immunity (vaccine effectiveness) after 2 doses. Side effects were mainly a mild flu-like reaction. These trial results have been submitted to the FDA for review. It is currently not known when the vaccine will be approved for use in children age 4 to 14.

2. My child has been bitten by a tick. What should I do?

If your child has been bitten by tick and the tick is no longer on the skin, you should monitor the bite site for the appearance of a rash. The rash (erythema migrans) can appear anywhere from 3 to 31 days after the bite. Preventive treatment (giving antibiotics in hopes of preventing disease) of a tick bite alone is not indicated routinely.

If the tick is still attached, you should remove the tick in the following way:

  • Get a pair of fine-pointed tweezers (the tips should align tightly)
  • Grasp the tick by the head–not the body (if the body breaks, this will increase the chance of the tick transmitting the disease)
  • Pull firmly and steadily until the tick releases
  • Do not apply petroleum jelly, alcohol or a hot match–this may increase the chances of transmitting Lyme disease

Analysis of ticks to look for the Lyme disease bacterium Borrelia burgdorferi is not routinely indicated.

3. Can I get Lyme disease from food?

According to the CDC, there is no evidence that Lyme disease can be transmitted by air, food or water. It cannot be passed through sexual contact, or from animals to people by direct contact. Thus far, there has not been any evidence that Lyme disease can be transmitted by mosquitoes, flies, or fleas.