Lyme Disease

What is Lyme disease?

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans by the bite of infected blacklegged ticks.

Within 1 to 2 weeks of being infected, people may have a "bull's-eye" rash with fever, headache, and muscle or joint pain. Some people have Lyme disease and do not have any early symptoms. Other people have a fever and other "flu-like" symptoms without a rash.

After several days or weeks, the bacteria may spread throughout the body of an infected person. These people can get symptoms such as rashes in other parts of the body, pain that seems to move from joint to joint, and signs of inflammation of the heart or nerves. If the disease is not treated, a few patients can get additional symptoms, such as swelling and pain in major joints or mental changes, months after getting infected.

How is Lyme disease diagnosed?

Lyme disease is diagnosed based on symptoms, objective physical findings (such as erythema migrans, facial palsy, or arthritis), and a history of possible exposure to infected ticks.  Validated laboratory tests can be very helpful but are not generally recommended when a patient has erythema migrans. 

When making a diagnosis of Lyme disease, health care providers should consider other diseases that may cause similar illness.  Not all patients with Lyme disease will develop the characteristic bulls-eye rash, and many may not recall a tick bite.  Laboratory testing is not recommended for persons who do not have symptoms of Lyme disease.

How is Lyme disease treated?

The National Institutes of Health (NIH) has funded several studies on the treatment of Lyme disease. These studies have shown that most patients can be cured with a few weeks of antibiotics taken by mouth. Antibiotics commonly used for oral treatment include doxycycline, amoxicillin, or cefuroxime axetil. Patients with certain neurological or cardiac forms of illness may require intravenous treatment with drugs such as ceftriaxone or penicillin.

Patients treated with antibiotics in the early stages of the infection usually recover rapidly and completely. A few patients, particularly those diagnosed with later stages of disease, may have persistent or recurrent symptoms. These patients may benefit from a second 4-week course of therapy. Longer courses of antibiotic treatment have not been shown to be beneficial and have been linked to serious complications, including death.

Studies of women infected during pregnancy have found that there are no negative effects on the foetus if the mother receives appropriate antibiotic treatment for her Lyme disease. In general, treatment for pregnant women is similar to that for non-pregnant persons, although certain antibiotics are not used because they may affect the foetus. If in doubt, discuss treatment options with your health care provider.

Can animals transmit Lyme disease to me?

Yes, but not directly. People get Lyme disease when they are bitten by ticks carrying B. burgdorferi. Ticks that carry Lyme disease are very small and can be hard to see. These tiny ticks bite mice infected with Lyme disease and then bite people or other animals, such as dogs and horses, passing the disease to them.

How can I protect myself from Lyme disease?

Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, landscaping, and integrated pest management. The ticks that transmit Lyme disease can occasionally transmit other tick-borne diseases as well.

• Whenever possible, you should avoid entering areas that are likely to be infested with ticks, particularly in spring and summer when nymphal ticks feed.
• If you are in an area with ticks, you should wear light-colored clothing so that ticks can be spotted more easily and removed before becoming attached.
• If you are in an area with ticks, wear long-sleeved shirts, and tuck your pants into socks. You may also want to wear high rubber boots (since ticks are usually located close to the ground).
• Application of insect repellents containing DEET (n,n-diethyl-m-toluamide) to clothes and exposed skin, and permethrin (which kills ticks on contact) to clothes, should also help reduce the risk of tick attachment. DEET can be used safely on children and adults but should be applied according to Environmental Protection Agency guidelines to reduce the possibility of toxicity.
• Since transmission of B. burgdorferi from an infected tick is unlikely to occur before 36 hours of tick attachment, check for ticks daily and remove them promptly. Embedded ticks should be removed by using fine-tipped tweezers. Cleanse the area with an antiseptic.
• You can reduce the number of ticks around your home by removing leaf litter, and brush- and wood-piles around your house and at the edge of your yard. By clearing trees and brush in your yard, you can reduce the likelihood that deer, rodents, and ticks will live there.