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Lyme Disease Fact Sheet

Baltimore County Department of Health
6401 York Road, Third Floor
Baltimore, Maryland 21212-2130  

Phone: 410-887-6011
TTY users call via Maryland Relay

Q. How do people get Lyme disease?

A. By the bite of a tick infected with Lyme disease bacteria.

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Q. How does Lyme Disease spread?

A. Young ticks become infected by feeding on small rodents, such as the white-footed mouse, and other mammals that are infected with the bacterium Borrelia burgdorferi. In later stages, these ticks then transmit the disease to humans and other mammals during the feeding process. Lyme disease is maintained in the blood systems and tissues of small rodents.

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Q. Could you get Lyme disease from another person?

A. No, Lyme disease is not transmitted from person-to-person. For example, you cannot get infected from touching or kissing a person who has Lyme disease, or from a health care worker who has treated someone with the disease, or by sexual contact.

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Q. What are the signs and symptoms of Lyme disease?

A. Within days to weeks following a tick bite, 80 percent of patients will have a red, slowly growing bull's-eye rash (called erythema migrans), accompanied by general tiredness, fever, headache, stiff neck, muscle aches, and joint pain. If untreated, weeks to months later some patients may develop arthritis, including intermittent episodes of swelling and pain in the large joints; neurological abnormalities, such as aseptic meningitis, facial palsy, motor and sensory nerve inflammation, inflammation of the brain; and, rarely, cardiac problems, such as atrioventricular block, acute inflammation of the tissues surrounding the heart or enlarged heart.

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Q. What is the incubation period for Lyme disease?

A. For the red bull's-eye rash (erythema migrans), usually 7 to 14 days following tick exposure. Some patients present with later manifestations without having had early signs of disease.

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Q. Can a person be re-infected with Lyme disease?

A. Yes. Having had Lyme disease does not protect against re-infection. Some persons have had Lyme disease more than once after re-exposure to infected ticks. Tick bite prevention such as wearing appropriate clothing when in tick-infested areas, daily tick checks, and quick removal of attached ticks is important.

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Q. How many cases of Lyme disease occur in the U.S.?

A. Lyme disease is the leading cause of vector-borne infectious illness in the U.S. with about 23,000 cases were reported in 2005, though the disease is greatly under reported. Twelve states account for over 90 percent of reported cases.

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Q. During what time of year does Lyme disease occur?

A. Lyme disease is most common during the late spring and summer months in the U.S. (May through August) when nymphal ticks are most active and human populations are frequently outdoors and most exposed. Additionally, most cases of Lyme disease generally are found in the northeastern and upper Midwest states.

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Q. Who is at risk for getting Lyme disease?

A. Persons who frequent areas where infected ticks are common, such as grassy or wooded locations favored by white-tailed deer in the northeastern and upper Midwest states, and along the northern Pacific coast of California.

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Q. How is Lyme disease treated?

A. According to experts, antibiotic treatment for 3 to 4 weeks is generally effective in early disease. Later disease, particularly with objective neurological manifestations, may require treatment with intravenous antibiotics for four weeks or more, depending on disease severity. In later disease, treatment failures may occur and re-treatment may be necessary. Get the latest treatment guidelines from Infectious Diseases Society of America.

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Q. Is taking antibiotics after a tick bite right for you?

A. Although this is not routinely recommended, it may be beneficial for some persons in areas where Lyme disease is common. Health care providers must determine whether the advantages of prescribing antibiotics after tick bite outweigh the disadvantages.

If you answer “yes” to the following questions, discuss the possibilities with your doctor or licensed health care provider.

  1. Were you in an area where Lyme disease is common when you acquired the tick bite? If you are unsure, look at the dark blue areas on this map.

  2. Was the tick attached for at least one full day?

  3. Has it been less than three days since you removed the tick or since it fell off of you?

Q. Is there a vaccine available against Lyme disease?

A. The vaccine for Lyme disease is no longer available. It was discontinued by the manufacturer in 2002, citing low demand. People who were vaccinated are no longer protected against Lyme disease, as protection was not long lasting. There are vaccines available for dogs but no vaccine is available for cats. Get additional vaccination information from the Centers for Disease Control and Prevention.

For questions or more information about Lyme disease, contact 410-887-6011 or email

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Revised March 2, 2015

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