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|  Lyme Disease (tick-borne borreliosis, Lyme arthritis)What is Lyme disease?Lyme disease is a tick-borne infection caused by the bacterium Borrelia burgdorferi. The disease was named for Old Lyme, Connecticut where it was first discovered. Lyme disease may cause symptoms affecting the skin, nervous system, heart and/or joints. In 2007, there were 417 cases reported among New York City residents (rate of 5 cases per 100,000 persons).
How is Lyme disease spread?In the eastern United States, Lyme disease is transmitted by the bite of the blacklegged tick Ixodes scapularis. The life cycle of the blacklegged tick progresses through four stages: eggs, larvae, nymphs, and adults. Larval and nymphal ticks become infected by feeding on infected small animals like white-footed mice. Nymphal and sometimes adult ticks feed on humans and if infected, may transmit the bacterium that causes Lyme disease. Tick larvae are not thought to be important in the transmission of Lyme disease to humans. Transmission from infected ticks does not occur until a tick has been attached and feeding for at least 24-36 hours. Person-to-person spread of Lyme disease does not occur. Transmission from an infected pregnant woman to her fetus is extremely rare. For more information on ticks and pictures, see http://www.nyc.gov/html/doh/html/ehs/ehstick.shtml Who gets Lyme disease?Anyone bitten by an infected deer tick can get Lyme disease. Individuals who spend time in grassy and wooded environments are at increased risk for exposure. Many people who get infected never become ill. Lyme disease is most common in the northeastern and mid-Atlantic states. The chances of being bitten by a deer tick are greater during times of the year when ticks are most active. Nymphal ticks, which are about the size of poppy seeds, feed on rodents, small mammals, birds, and humans in the late spring and summer. Adult ticks, which are approximately the size of apple seeds, feed and mate on large mammals (especially deer) and bite humans in the fall and early spring, Ticks can be active any time temperatures are above freezing. Where and when does transmission of Lyme disease occur?Transmission risk is greatest in the northeastern and mid-Atlantic regions of the United States and is also high in eastern Minnesota and western Wisconsin. Infected blacklegged ticks can be found throughout New York State but they are rarely found in New York City. Lyme disease transmission occurs in nearly all areas surrounding New York City, including southern New York State (Westchester, Nassau and Suffolk counties), New Jersey, and Connecticut. Recent findings have shown that up to 94% of new infections among NYC residents were acquired while they were traveling outside of the City. Transmission risk is greatest during the spring and summer when nymphal ticks are most abundant. Because of their small size they often go unnoticed and may remain attached for longer periods of time, increasing the likelihood of transmission. Adult blacklegged ticks are most abundant in the fall and winter. Due to their somewhat larger size, they are easier to spot than nymphs, and are therefore more likely to be removed before transmission can occur. Adult ticks tend to be responsible for cases that occur in the cooler months. What are the symptoms of Lyme disease?Early symptoms usually develop within 7-14 days after exposure but may develop anywhere from 3-32 days after exposure. About 60-80% of patients develop a large, reddish, slowly expanding rash (referred to as erythema migrans (EM) or a target lesion) around or near the site of the bite. Sometimes multiple rash sites appear. Other symptoms, such as fever, headache, fatigue, stiff neck, muscle and/or joint pain, may develop. If left untreated, within a few weeks to months, complications, such as meningitis, facial palsy, or heart abnormalities may occur. Later symptoms may develop in people who did not have early symptoms or did not recognize them. Swelling and pain in the large joints may recur over many years.
Does past infection with Lyme disease make a person immune?No. Reinfection is possible, so if you have had Lyme disease in the past, remain vigilant about protecting yourself against tick bites. It is also important to note that the blacklegged tick can also potentially transmit other tick-borne diseases like babesiosis and ehrlichiosis. For more information on other tick-borne diseases, see Babesiosis and Ehrlichiosis. How is Lyme disease diagnosed?A physician can diagnose Lyme disease by observing the characteristic erythema migrans rash. In the absence of a physician-diagnosed rash, diagnosis is based on a history of clinically compatible symptoms in conjunction with Lyme antibody testing. The Centers for Disease Control (CDC) recommends a two-step process when testing blood for evidence of Lyme disease. Both steps can be done using the same blood sample. The first step uses an ELISA (Enzyme-Linked ImmunoSorbent Assay) or IFA (ImmunoFluorescence Assay) test and the second step a Western blot test. These tests may be falsely negative in patients with early disease, but they are quite reliable for diagnosing later stages of disease. Other Types of Laboratory Testing Some laboratories offer Lyme disease testing using assays whose accuracy and clinical usefulness have not been adequately established. These tests include urine antigen tests, immunofluorescent staining for cell wall-deficient forms of Borrelia burgdorferi, and lymphocyte transformation tests. In general, CDC does not recommend these tests. Patients are encouraged to ask their physicians whether their testing for Lyme disease was performed using validated methods and whether results were interpreted using appropriate guidelines. What is the treatment for Lyme disease?Current therapy involves the use of antibiotics, such as doxycycline or amoxicillin. Prognosis is improved with prompt diagnosis and appropriate, early treatment. What can be done to prevent Lyme disease?When in tick infested areas (i.e., tall grass, overgrown brush, etc.), special precautions should be taken. Wear light-colored clothing, tuck pant legs into socks, and wear closed toe shoes. The risk of tick attachment can also be reduced by applying insect repellents containing no more than 20% - 30% DEET (n,n-diethyl-m toluamide) to clothes and exposed skin, and applying permethrin (which kills ticks on contact) to clothes. Use repellents sparingly and with care, as they may cause side effects. DEET can be used safely on children and adults but should be applied according to Environmental Protection Agency (EPA) guidelines to reduce the possibility of toxicity. Avoid application to damaged skin. When returning from outdoors it is important to check yourself, your children, and your pets for ticks. Look for ticks in all joint areas, the navel, behind ears, in the hairline, and in other skin folds. Wash all skin treated with insect repellent thoroughly. Keep your lawn mowed, cut overgrown brush, and remove leaf litter to reduce tick populations. For more information on insect repellent safety, see Repellent Fact Sheet. How should a tick be removed?
Is there a vaccine for Lyme disease?There is currrently no approved vaccine for Lyme disease. Related Information
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