Lyme Disease


Lyme disease is caused by a bacteria called Borrelia burgdorferi transmitted by deer ticks (Ixodes dammini). It is most common from May until August. Although it is not known what percentage of deer ticks in the Westport/Fall River area are infected with the germ causing Lyme disease, a reasonable estimate is 10-50%. Even if you are bitten by a deer tick that is infected, you still have a good chance of not developing Lyme disease; factors that are important are how deep the tick has borrowed into your skin and how long the tick remained in place (in studies done on animals, it has been found that the tick has to feed on the animal for 48 to 72 hours in order to transmit the disease).


Symptoms of Lyme disease

There are three stages of Lyme disease. Within a few days after the bite, you will develop a red bump over the area of the bite, usually (in 50-70% of infections) followed in about 3-30 days by a flat red rash the spreads over about 7 days. During this time, you may develop a headache, fever, joint pains, swollen glands and pink eye. If you are treated with the right antibiotic at this time, the symptoms will go away (although, even among those people treated promptly, some may go on to have mild joint pains for a few months).

The second stage occurs weeks to months after the tick bite. It is characterized by nerve palsies (a condition in which a nerve stops working properly; the most common type is Bell's palsy, where half of the face droops for a few weeks or months) or encephalitis (characterized by fever, neck stiffness, and headache).

The third stage of Lyme disease occurs 4 weeks or more after the tick bite (the third stage can occasionally occur years after the initial infection). It is characterized by repeated attacks of arthritis (pain, swelling and redness in a joint), usually in large joints, like the knee.


Treatment of Lyme disease

Treatment for Lyme disease is most effective if begun shortly after symptoms develop. It is important to recognize the symptoms of Lyme disease and seek medical care early. Adults are usually treated with tetracycline or doxycycline for 10-14 days (it is important to wear a good sunscreen when taking these medicines, as they can cause a bad sunburn with even short exposure to the sun). Children are usually treated with amoxicillin for 10-14 days.

What if I am bitten by a tick? Since it is unlikely that you will get Lyme disease from one tick bite, I do not recommend treatment unless you have symptoms that suggest Lyme disease. In certain circumstances, however, I might suggest prophylactic treatment. The reason I do not recommend treating everybody exposed to a tick bite is because the antibiotics themselves have side effects, and I would be treating a lot of people needlessly. Blood tests done right after the tick bite will not be helpful; it takes your immune system about 2 weeks to develop detectable antibodies to the Lyme disease germ (the blood tests are not terribly reliable even after this 2 week period).

If you develop no symptoms in the 2 weeks after the tick bite, it is very unlikely that you will have any problems. However, if you develop any of the stage 2 or 3 symptoms over the month following the tick bite, be sure to see your doctor and discuss your concerns. A blood test at this time (2-4 weeks after the bite) may help us determine whether or not you have been exposed to Lyme disease.

How do I remove a tick? There is no sure-fire way to remove all of the tick if it is burrowed deep in your skin. The best advice is to put on a rubber glove and grasp the tick as close to its head as possible, and pull with steady force. If part of the tick's mouth parts are left in the skin, do not worry. Simply clean the area well, put on a topical antibiotic (like Bacitracin or Neosporin). The debris will work its way out of the skin within a few days. Methods such as putting a hot match to the tick, putting petroleum jelly on the tick, or pouring alcohol on the tick are simply not effective.


Prevention of Lyme disease

Apply a low-concentration DEET insect repellent (like Cutter Insect Repellent with 17.9% DEET) to exposed skin sparingly; avoid applying multiple times, especially on young children (DEET can produce convulsions if used in too high a concentration or applied too many times in one day). Spray clothing with 0.5% permethrin (like Coulston's Permethrin Tick Repellent); one treatment can help keep ticks away for up to one month. Wear long pants and long-sleeve shirts whenever possible.

Lyme disease is generally a fairly mild illness. I hope that this information sheet has answered most of your questions about Lyme disease. Be sure to ask me any questions that still bother you.


Incidence of Lyme disease in various counties in Massachusetts in 2005 (cases reported per year per 100,000 people):