Travel Medicine

Emerging Infectious Diseases and Other Conditions

Lyme Disease

The danger of tick bites:
While most tick bites are harmless, several species can cause life-threatening diseases. Two of these well-known diseases are Rocky Mountain Spotted Fever and Lyme disease. Ticks can also transmit tularemia (a plague-like disease in rodents that can be transmitted to man), relapsing fever, and a newly identified ailment called ehrlichiosis (an abrupt illness consisting of fever, rash, nausea, vomiting, and weight loss).

What is Lyme disease?

Lyme disease (LD) is a multi-stage, multi-system bacterial infection caused by the spirochete Borrelia burgdorferi, a spiral shaped bacterium that is most commonly transmitted by a tick bite. According to the Centers for Disease Control and Prevention (CDC), Lyme disease continues to be a rapidly emerging infectious disease, accounting for more than 90 percent of all reported vector-borne illness reported in the United States. A mean of approximately 12,500 cases annually were reported by states to the CDC from 1993-1997. The disease takes its name from Lyme, Connecticut, where the illness was first identified in the United States in 1975.

What types of ticks transmit LD?

Ixodes scapularis (Deer tick)
Ixodes dammini
Amblyomme americanum (Lone Star tick)
Ixodes pacificus

Ticks prefer to live in wooded areas, low-growing grasslands, seashores, and yards. Depending on the location, anywhere from less than 1 percent to more than 90 percent of the ticks are infected with spirochetes.

Lyme disease is a year round problem, although, April through October is considered tick season, with ticks being very active in the spring and early summer. Cases of Lyme disease have been reported in 45 states in the US and in large areas in Europe and Asia.

What are the symptoms of Lyme disease?

The list of possible symptoms is long, and symptoms can affect every part of the body. The following are the most common symptoms of Lyme disease. However, each individual may experience symptoms differently:

The primary symptom is a red rash that:

can appear several days after infection, or not at all.
can last a few hours or up to several weeks.
can be very small or very large (up to 12 inches across).
can mimic such skin problems as hives, eczema, sunburn, poison ivy, flea bites.
can itch or feel hot, or may not be felt at all.
can disappear and return several weeks later.

Several days or weeks after a bite from an infected tick, a patient usually experiences flu-like symptoms such as:

headache
stiff neck
aches and pains in muscles and joints
low-grade fever and chills
fatigue
poor appetite
sore throat
swollen glands

After several months, arthritis-like symptoms may develop, including painful and swollen joints.

Other possible symptoms may include:

neurological symptoms
heart problems
skin disorders
eye problems
hepatitis
severe fatigue
limb weakness
poor motor coordination

Some people may develop post-Lyme disease syndrome (PLDS), a condition also known as chronic Lyme disease, characterized by persistent musculoskeletal and peripheral nerve pain, fatigue and memory impairment.

How is Lyme disease diagnosed?

Lyme disease is difficult to diagnose because symptoms are not consistent and may imitate other conditions. The primary symptom is a rash, but it may not be present in up to 25 percent of cases.

Diagnosis for Lyme disease is a clinical one and must be made by a physician experienced in recognizing LD. Diagnosis is usually based on symptoms and a history of a tick bite. Testing is generally done to eliminate other conditions and may be supported through blood and laboratory tests, although these tests are not absolutely reliable for diagnosing LD.

Research is underway to develop and improve methods for diagnosing LD.

Always consult your physician for a diagnosis.

Treatment for Lyme disease:
Your physician will determine the best treatment plan based on your individual situation. Lyme disease is usually treated with antibiotics for a period of four to six weeks.

Treatment will be considered based on these and other factors:

If you are bitten by a tick that tests positive for spirochetes.
If you are bitten by a tick and have any of the symptoms.
If you are bitten by a tick and are pregnant.
If you are bitten by a tick and live in an endemic, high-risk area.

Relapse and incomplete treatment responses occur. Complications of untreated early-stage disease include: 40 to 60 percent joint disease; 15 to 20 percent neurologic disease; 8 percent carditis; and 10 percent or more are hospitalized, some with chronic debilitating conditions.

How can LD be prevented?

A vaccine against LD has been available for dogs, and in 1998 the US Food and Drug Administration (FDA) approved a new vaccine against Lyme disease for humans. Called LYMErix, this vaccine was withdrawn from the market in 2002. Other recommendations for preventing Lyme disease include:

Dress appropriately by wearing:

light-colored clothing
long-sleeved shirts
socks and closed-toe shoes
long pants with legs tucked into socks

Frequently check for ticks on:

all parts of the body that bend: behind the knees, between fingers and toes, and underarms.

other areas where ticks are commonly found: belly button, in and behind the ears, neck, hairline, and top of the head.

areas of pressure points, including:

where underwear elastic touches the skin

where bands from pants or skirts touch the skin

anywhere else where clothing presses on the skin

Visually check all other areas of the body, and run fingers gently over skin.

Also:

Shower after all outdoor activities are over for the day.

When a tick is found, remove it carefully and do not squeeze the body. Remember that any method of removal could cause transmission of the bacteria.

Ticks can be tested for spirochetes, so place the removed tick in a glass, plastic vial, or plastic storage bag with a moistened cotton swab.

Consider using repellents:

Products that contain DEET are tick repellents, but do not kill the tick and are not 100 percent effective in discouraging a tick from feeding on you.

Products that contain permethrin are known to kill ticks, however, they should not be sprayed on the skin but on clothing.

Check pets and children for ticks.

This page was last updated on: February 14, 2008.

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