Lyme Disease - May 25, 2010 Newsletter

Lyme Disease

EHE Newsletter, Volume 10, Number 21
May 25, 2010

Now that summer is just around the corner, tick season has arrived. Gardeners, hikers and outdoor enthusiasts need to be aware of the risk of tick bites and be vigilant in protecting themselves from Lyme disease. According to the Centers for Disease Control and Prevention (CDC), Lyme disease is a rapidly emerging infectious disease and is the leading cause of all insect–borne illness in the U.S. Over 28,000 confirmed cases and 6,277 probable cases of Lyme disease were reported nationwide in 2008.

What is Lyme Disease?

Lyme disease is a multi–stage, multi–system bacterial infection that is caused by Borrelia burgdorferi — a spiral–shaped bacterium (spirochete) that is most commonly transmitted by a tick bite. In the northeastern and north–central United States, Lyme disease is transmitted by the deer tick. Deer ticks (Ixodes scapularis; also called "blacklegged ticks") are most often found in grassy and heavily wooded areas and are especially common where the two areas merge. These ticks are often no bigger than the head of a pin, making them nearly impossible to detect. Deer ticks typically feed on the blood of white–footed mice, small birds and deer, though they can also feed on the blood of humans, cats, dogs and horses. In the Pacific coastal U.S., Lyme disease is spread by the western blacklegged tick (Ixodes pacificus).

Individuals who are bitten by an infected tick can become infected with the Lyme disease bacteria. Ticks will attach themselves to any part of the body, but prefer body creases such as the armpit, groin, back of the knee and nape of the neck. Ticks can bite year–round; however, peak tick season is April through September in the Northeast, and November through April on the West coast.

Symptoms

The first symptom that most people (approximately three–quarters of those who become infected) experience is a red, expanding rash called "erythema migrans." An erythema migrans rash generally starts as a small red spot at the site of the tick bite. Over a period of days or weeks, the spot grows larger and forms a red rash that is shaped like a circle or an oval. The rash may resemble a bull’s eye as it sometimes appears as a red ring that surrounds a clear center area. The rash can range in size from that of a dime to the entire width of a person’s back. As infection spreads, rashes can appear at different sites on the body.

The rash is often accompanied by other symptoms which can last from a few days to a few weeks. These symptoms include:

• Fever
• Headache
• Stiff neck
• Body aches
• Fatigue

Although these symptoms may be similar to those of common viral infections such as the flu, Lyme disease symptoms tend to continue longer or may come and go.

If the infection is left untreated, the majority of those affected will develop recurrent attacks of painful and swollen joints that last for a few days to a few months. Lyme disease can also cause neurological complications including inflammation of the membranes surrounding the brain (meningitis), temporary paralysis of facial muscles (Bell’s palsy), pain or weakness in the limbs, numbness and impaired muscle movement. These complications may occur weeks, months or even years after an untreated infection. Memory loss, difficulty with concentration and a change in mood or sleeping habits have also been associated with Lyme disease. Less commonly, individuals who have not taken antibiotics may develop heart or other problems weeks, months or even years after infection. Eye inflammation, hepatitis and severe fatigue may also occur, although none of these symptoms are likely to appear without other Lyme disease symptoms being present.

Diagnosis and Treatment

Lyme disease may be difficult to diagnose because many of its symptoms mimic those of other disorders. Additionally, not all individuals with Lyme disease will develop the characteristic bull’s eye rash, and many may not recall being bitten by a tick because ticks are so small and their bites are usually painless. For individuals who have Lyme disease symptoms but do not develop the distinctive rash, their healthcare providers will rely on medical history and careful physical exams for diagnosis. Laboratory tests to identify antibodies to the bacteria may be used to help confirm a diagnosis. These tests are most reliable a few weeks after an infection, after the body has had time to develop antibodies.

Individuals treated with antibiotics in the early stages of the infection usually recover quickly and completely after three to four weeks of oral antibiotics. Antibiotics that are commonly used for oral treatment include doxycycline, amoxicillin or cefuroxime axetil. Individuals who experience symptoms with neurological or cardiac involvement may require intravenous treatment with medications such as ceftriaxone or penicillin.

Prevention

Fortunately, the cause of Lyme disease is known and the disease can be prevented. The best protection against Lyme disease is to avoid contact with ticks. Studies have shown that an infected tick normally cannot begin transmitting the infection until it has been attached to its host for approximately 36 to 48 hours. If avoiding areas where ticks are likely to be is not possible, the best line of defense against Lyme disease is to perform a self–examination after potential exposure and remove any ticks before they become engorged (swollen) with blood. Removing them promptly can help prevent infection.

According to the CDC, a tick should be removed from the skin as soon as possible. Instructions: Use fine–tipped tweezers to firmly grasp the tick very close to the skin. With a steady motion, pull the tick’s body away from the skin and clean the skin with soap and warm water. The dead tick should be thrown away with the household trash. If the tick’s mouthparts remain in the skin, do not be alarmed. Once the mouthparts are removed from the rest of the tick, it can no longer transmit the Lyme disease bacteria. Avoid crushing the tick’s body. If the tick is crushed accidentally, clean the skin with soap and warm water or alcohol. Never use petroleum jelly, a hot match, nail polish or other products to remove a tick.

To keep ticks off of the skin, the CDC recommends the following tips:

Know where to expect ticks. Ticks live in moist and humid environments, particularly in or around wooded or grassy areas. Individuals may come into contact with ticks during outdoor activities around the home or when walking through vegetation such as leaf litter or shrubs. Hikers should walk in the center of trails to avoid ticks.

Use insect repellant. Adults should use insect repellent with 20 to 30 percent DEET (chemical name: N, N-diethyl–meta–toluamideon) on exposed skin and clothing to prevent tick bites. A ten percent concentration should be used on children. Clothes and other fabrics (tent walls, mosquito nets, etc.) can be sprayed with permethrin which kills ticks on contact. When applied to clothing by aerosol or trigger spray, permethrin provides protection which lasts up to two weeks or two washings, whichever comes first. Permethrin should not be applied directly to skin.

Wear protective clothing. Individuals should wear long pants, long sleeves and long socks to keep ticks off of the skin and wear light–colored clothing to spot ticks easily. Pant legs should be tucked into socks or boots and shirts should be tucked into pants in order to keep ticks on the outside of clothing.

Perform daily tick checks after being outdoors. Individuals should check their bodies for ticks after being outdoors. A hand–held or full–length mirror is recommended so that all parts of the body can be viewed and ticks can be removed immediately. Special attention should be paid to following areas:

• Under the arms
• In and around the ears
• Inside belly button
• Back of the knees
• In and around the hair
• Between the legs
• Around the waist

Keep yards safe. Leaf litter should be removed, lawns should be mowed and tall grass and brush should be cleared around homes and at the edges of lawns. Wood chips or gravel should be placed between lawns and wooded areas to restrict tick migration. Wood should be stacked neatly in dry areas. Playground equipment, decks and patios should be kept away from yard edges, shrubs, trees and other vegetation.

If you believe that you may have Lyme disease, it is important that you consult your healthcare provider for proper diagnosis. In general, the sooner that treatment begins following infection, the quicker and more complete the recovery.

MEDICAL DISCLAIMER: The information is not intended to constitute medical advice and is not a substitute for consultation with a physician or other healthcare provider. Individuals with specific complaints should seek immediate consultation from their personal physicians.