What is lyme disease?
In recognition of Lyme Disease Awareness month this May, the Centers for Disease Control and Prevention (CDC) encourages Americans to learn about this common tick-borne disease and take steps to protect themselves if they live in or visit areas with Lyme disease activity. Statistics from the CDC indicate that there has been a progressive rise in the number of cases of Lyme disease diagnosed. In fact, it is now the most commonly reported vector-borne illness (disease transmitted to humans by ticks, mosquitoes or fleas) in the United States, with around 30,000 new cases each year. In 2010, 94% of Lyme disease cases were reported from 12 states, mostly in the northeastern U.S., near the town where the disease gets its name—Lyme Connecticut.
What causes Lyme disease? Lyme disease is an infection caused by a type of bacteria known as Borrelia burdorferi. The infection is most often acquired from the bite of an infected deer tick, also known as a black-legged tick. Ticks that spread the infection are in the nymph stage of their life cycle and are quite small when compared to the adult ticks. The infection is spread when a young tick feeds on an infected animal, taking Borrelia bacteria into its body. If the tick then feeds on a human, the bacteria can be passed along to its new host. There is no evidence that Lyme disease can be passed on from person-to-person.
What is the first sign that someone may have Lyme disease? Lyme disease produces different manifestations at different times during the course of the illness. The first sign of an infection is usually a rash called erythema migrans (EM). This is a circular rash that develops at the site of the tick bite. This rash occurs in approximately 70-80% of those infected, appearing anywhere from a few days to a month after the tick bite. EM gradually expands over a period of several days and can reach up to 12 inches in diameter. Sometimes the center of rash clears, resulting in a “bull’s eye” appearance.
What symptoms are associated with Lyme disease? Along with the rash, most people with early Lyme disease develop symptoms such as fatigue, chills, fever, headache, muscle and joint aches. If treatment is not begun, other symptoms develop within days to weeks. These include facial paralysis, headaches, neck stiffness, heart palpitations and “migratory” joint pain which moves from joint to joint. Late manifestations of the disease includes arthritis, particularly affecting large joints, such as the knees, and neurological complaints including mental status changes, altered sensation, malaise, headache, and sleep disturbance.
Is there a test available to diagnose Lyme disease? The tests used in diagnosing Lyme disease are most accurate a few weeks after an infection develops. This is when the body has begun producing antibodies to fight the infection. The CDC currently recommends a two-step process when testing blood for evidence of antibodies against the Lyme disease bacteria. The first step involves procedure called “EIA” (enzyme immunoassay). If this first step is negative, no further testing of the specimen is recommended. If the first step is positive, a second step called an immunoblot test, or “Western blot”, is performed. The laboratory diagnosis of Lyme disease is confirmed only when both the EIA and immunoblot are positive.
How is Lyme disease treated? Most cases of Lyme disease can be cured with antibiotics, especially if treatment is begun early in the course of illness. Antibiotics that are effective for Lyme disease include doxycycline, amoxicillin, and cefuroxime axetil (Ceftin).
Can Lyme disease be prevented? To prevent Lyme disease and other tick-borne diseases, the CDC recommends that people:
- Avoid areas with high grass or leaf litter and walk in the center of trails when hiking.
- Use repellent that contains 20%-30% DEET on exposed skin for protection that lasts several hours. Parents should apply repellent to children; the American Academy of Pediatrics recommends products with up to 30 percent DEET for kids. Always follow product instructions!
- Use products that contain permethrin to treat clothing and gear, such as boots, pants, socks and tents or look for clothing pre-treated with permethrin.
- Bathe or shower as soon as possible after coming indoors to wash off and more easily find crawling ticks before they bite you.
- Conduct a full-body tick check using a hand-held or full-length mirror to view all parts of your body upon returning from tick-infested areas. Parents should help children check thoroughly for ticks. Remove any ticks right away.
- Seek health care promptly if symptoms of Lyme disease develop, including fever, rash, and muscle or joint pain.
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