Lyme Disease

Introduction

In 2005, more than 23,000 cases of Lyme disease were reported to the Centers for Disease Control and Prevention. The incidence of Lyme disease has increased over the past 20 years due to the increasing number of people living in the woodlands and the increasing number of deer in suburban yards. Deer carry ticks that spread Lyme disease. People are at risk for contracting Lyme disease in any outdoor environment, even in their own backyards. However, some outdoor environments put people at a greater risk for Lyme disease than others.

What is it?

Lyme disease is an infection that is transmitted by ticks when they attach and imbed on a human body. Not all ticks transmit Lyme disease; however, cases of Lyme disease have been reported throughout the United States, Europe, and Asia. Lyme disease is characterized by symptoms including a rash that looks like a ?bull?s eye?, fever, fatigue, and headache. If left untreated the infection can spread to the joints, nervous system, and the heart, causing symptoms of arthritis, trouble concentrating, loss of memory, muscle weakness, and numbness and tingling in the arms and legs. If treated early, Lyme disease is curable in most patients. Because, Lyme disease is potentially incurable (if not detected early) it is important to protect yourself and your family from the disease. Prevention of tick bites is the best defense humans have against Lyme disease.

What causes it?

Lyme disease is caused by bacteria called Borrelia burgdorferi which is found in small animals such as squirrels, mice, and rabbits. Ticks pick up Borrelia burgdorferi from feeding on an infected host and then carry the bacteria in their guts. Ticks can then transmit the Borrelia burgdorferi bacteria to humans or other animals that they attach to. The tick must generally be attached to the host for 48 hours before enough of the Borrelia burgdorferi bacteria can be transmitted to establish an infection. Not all ticks carry Lyme disease. It is relatively rare to contract Lyme disease from a single tick bite. Checking yourself for ticks daily can help prevent Lyme disease.

Who has it?

Anyone can get Lyme disease. As stated in the introduction section, over 23,000 cases of Lyme Disease were reported to the Centers for Disease Control and Prevention in 2005. This translates to an average of 7.9 cases for every 100,000 persons living in the United States. However, in the 10 states where Lyme disease is most common, the average was 31.6 cases for every 100,000 persons. Lyme disease is only transmitted through ticks; there is currently no evidence of it being contracted any other way. Ticks are attracted to warm bodies, no matter the age or sex. Dogs and cats can get Lyme disease just like humans. The infection can not be spread directly from the dog or cat to a human; however, these pets can carry infected ticks inside the house. There are over 850 species of ticks; about 100 species of ticks are capable of transmitting Lyme disease. The ticks that most commonly spread Lyme disease in the United States are often called Deer Ticks, because deer carry these ticks. Interestingly, deer do not get Lyme disease.

What are the risk factors?

Risk factors are characteristics that predispose a person to develop a condition. Risk factors for contracting Lyme disease are:

  • Location - Some states have a higher incidence of Lyme disease than others. The 10 states that have the most reported cases of Lyme Disease yearly include New York, New Jersey, Connecticut, Pennsylvania, Wisconsin, Minnesota, Maryland, Delaware, New Hampshire, and Maine. Increased risk in these areas can be attributed to a greater amount of wooded areas and a larger quantity of deer.

  • Outdoor Activity - Spending a lot of time in wooded areas or areas with tall brush where ticks can be found put you at higher risk of a tick bite. Camping, fishing, and hunting in areas where ticks are found can also increase your risk.

  • Pets- Pets can carry ticks indoors which will increase your risk for Lyme disease.

What are the symptoms?

Symptoms of Lyme disease will vary from person to person at different times in the course of the disease. The first symptom in most patients is a rash that looks like a ?bull?s eye,? called an erythema migrans rash, at the site of the tick bite. The rash usually appears within 3 to 30 days of the tick bite and can reach up to 12 inches in size. Other symptoms of infection are flu-like and may include fever, fatigue, chills, headache, and muscle aches. These symptoms occur in what is known as Phase 1 of the infection. If not treated in phase 1, Lyme disease will progress to Phase 2.

Phase 2 of Lyme disease can begin within days to weeks of the beginning of the infection. Symptoms that occur in Phase 2 are mainly related to the nervous system. These symptoms include loss of muscle tone in the face (Bell?s palsy), heart palpitations, and dizziness. The infection may turn into meningitis with symptoms such as severe headache and neck stiffness. Other symptoms that may occur in this phase include sore throat, shooting pains or numbness and tingling in the hands or feet. These symptoms may go away without treatment, but the patient is still infected.

Phase 3 of Lyme disease occurs several months after the initial infection and lasts for years after the infection. Symptoms that occur in Phase 3 are known as arthritic symptoms such as joint pain and swelling, occurring most frequently in the knees. Some patients can also have problems concentrating and experience a loss in short-term memory.

How is it treated?

Lyme disease is treated with antibiotics such as doxycycline, amoxicillin, cefuroxime, azithromycin, and ceftriaxone. When treated in the early phases, Lyme disease is curable in most patients with a short course (10 to 21 days) of antibiotics. When treated early, patients often have a fast recovery. Late phase Lyme disease is treated with longer courses of antibiotics (up to 28 days), and Lyme disease with nervous system symptoms including meningitis may require treatment with intravenous antibiotics. Although most cases resolve following a 10-28 day course of antibiotics, treatment of Lyme disease does not always grant a cure. Some patients suffer from the disease with persistent or recurrent symptoms for years. Whether these individuals should receive repeat or prolonged therapy with antibiotics is currently controversial.

The best thing to do is to prevent Lyme disease. You can prevent Lyme disease by preventing tick bites. Ticks are out in full force in the U.S. in May, June, and July so pay special attention when going outdoors during these months. To prevent tick bites use insect repellants with 20%-30% DEET on adults and 10% DEET on children, wear long pants, sleeves, and socks. Check yourself for ticks daily. Remember even if you get a tick bite, it can take up to 48 hours for the infection to begin so prompt removal of the tick can help prevent Lyme disease.

Proper Tick Removal

  • Do not try to remove the tick with a match or any substances.
  • With fine point tweezers grasp the tick as closes to the skin as possible.
  • Gently pull the tick straight out in one smooth motion.
  • Wash area around the tick bite and hands with soap and warm water.
  • Place the tick (dead or alive) in a small container, making sure the tick can not get out if it?s alive. Monitor your skin and body?s reaction to the bite for up to 30 days. If a rash or other symptoms possibly related to Lyme Disease develop, take the container to your doctor. The doctor may want to test the tick for Borrelia burgdorferi bacteria.

    What is on the horizon?

    The evolution of Lyme disease is not fully understood. Researchers are currently studying how the infection develops over a course of time. Better understanding of the development of the disease will be helpful in developing specific criteria for diagnosing Lyme disease. Researchers are also looking for optimal therapy to treat patients in the later stages or who have persistent, recurrent, or refractory disease.

    References

    American Lyme Disease Foundation, Inc. Available at http://www.aldf.com. Accessed July 24, 2007.

    Bauman, Robert W. Microbiology. Pearson Benjamin Cummings Press, 2004.

    Burgess DS, Abate BJ. Spirochetes. In: Pharmacotherapy A Pathophysiologic Approach. 6th ed. Dipiro JT, Talbert RL eds. Stamford, CT;Appleton and Lange: 2005: 1921.

    Centers for Disease Control and Prevention: Lyme Disease. Available at http://www.cdc.gov/ncidod/dvbid/lyme. Accessed July 24, 2007.

    Clinical Trials.gov: Lyme Disease. Available at http://www.clinicaltrials.gov. Accessed July 24, 2007.

    Lyme Disease Foundation. Available at http://www.lyme.org/. Accessed July 24, 2007.

    The ILADS Working Group. Evidence-based guidelines for the management of Lyme disease. Expert Review in Anti-infective Therapies 2004; 2(1): S1-S13. Available at http://www.ilads.org/files/ILADS_Guidelines.pdf. Accessed July 24, 2007.

    Wormser GP, et al. The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America. Clinical Infectious Diseases 2006; 43: 1089-134. Available at http://www.journals.uchicago.edu/CID/journal/issues/v43n9/40897/40897.web.pdf. Accessed July 24, 2007.

    Lyme Disease Health Condition Last Updated: July 2007

    Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It is not intended to diagnose a health condition, but it can be used as a guide to help you decide if you should seek professional treatment or to help you learn more about your condition once it has been diagnosed.

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