The Carlisle Mosquito Online

Friday, May 31, 2002

News

Lyme disease: When do I call my doctor?
Most people who live in New England are aware of Lyme disease and each year more of us are coming by that knowledge based on personal experience. Lyme disease is an extremely complex constellation of clinical syndromes, a detailed description of which is well beyond the scope of this piece. However, there are some important aspects that are worth sharing. This information may help you decide when to seek medical care in the context of a tick bite.

Obviously, if you can avoid getting bitten by a tick you will not contract Lyme disease. Long sleeves and long pants tucked into socks or boots will help protect you from ticks. This kind of clothing is comfortable during cool spring weather, but it will spoil your walk in the woods when temperatures rise. In summer, short sleeves and short pants are appropriate, but you should be extra vigilant about tick checks when you finish with your outside activities. Ticks like warm, dark parts of the body; they tend to choose the torso or scalp. So, these are the areas that need the most scrutiny.

Differentiating between ticks

Actual size (left to right) larva, nymph, adult male, adult female, and engorged adult female deer ticks and adult male and female dorg ticks.

Locally we encounter ticks of two different sizes, big ticks and little ticks. Big ticks do not carry the organism that causes Lyme disease (a bacterium called borrelia burgdorfi). They are the size of a small cucumber seed. When engorged, they are the size and shape of a sunflower seed. If you find one of these attached to you, remove it by grasping it between your fingertips or with tweezers and pulling firmly. Usually you do not need to consult a physician for this kind of a tick bite.

Little ticks, commonly known as deer ticks, are the ones that transmit Lyme disease. Adult deer ticks are a little larger than the head of a pin. Many of the local deer ticks carry borrelia burgdorfi (the organism that causes Lyme disease) which they will pass to their host at the end of their blood meal, typically after 24 hours of attachment. If you find a small tick on you and you remove it shortly after it has attached (before it is engorged) you will not contract Lyme disease. If you find a small, engorged tick attached to you, one that could have been attached for 24 hours, you should remove the tick and contact your doctor. A single dose of doxcycline (a tetracycline antibiotic) taken under these circumstances will significantly decrease your chance of developing Lyme disease. Ideally the antibiotic is taken within 24 hours of finding the tick.

Immature deer ticks are as likely to transmit Lyme disease as adults, but they are more difficult to identify because they are tiny. Immature ticks need to eat when the weather is cold; they are dormant only at temperatures below freezing. Fortunately, this is when we are wearing long sleeves and long pants. So, as we protect ourselves from the cold we also tend to protect ourselves from ticks. Nonetheless, these tiny ticks sometimes penetrate the most daunting of clothing. So, if you think you may have the signs or symptoms of Lyme disease but cannot imagine how you could have been exposed to a tick in the winter, see your doctor. Lyme disease is a year-round problem in Eastern Massachusetts.

Diagnosing the disease

Enlarged photo shows size difference between Dog tic (top) and Deer Tick.
New England Journal of Medicine, 1992


Symptoms of acute Lyme disease appear 10 to 14 days after the offending tick bite. They include fever, malaise, a target-like rash (the center of which is the site of the tick bite), muscle and joint aches. Some people will have mild complaints; others will be very sick. If you have a syndrome that includes some or all of these symptoms you should see your doctor. At this stage medical personnel cannot confirm a diagnosis of Lyme disease with laboratory testing, but rely on clinical experience to make the diagnosis. However, since a two-week course of antibiotics will cure acute Lyme disease, antibiotics are usually prescribed if acute Lyme disease is suspected. The sooner you start antibiotics, the sooner the symptoms of Lyme disease will subside. But, at this stage there is no critical time frame for initiation of therapy.

Not everyone who gets Lyme disease experiences this acute syndrome. Some people have no illness at the time they are first infected with borrelia burgdorfi. Instead, they develop a different illness about eight weeks after exposure. This is called latent Lyme disease. Symptoms can vary enormously but often include profound fatigue and low-grade fevers. Joint symptoms are common; the classic description is of painful, red, hot, swollen joints. Typically only one or two joints will be affected and they will be asymmetric (for instance a knee and a shoulder, not both knees). Diffuse swelling and stiffness of the joints of the hands and feet can also be seen in latent Lyme disease. Sometimes the joints are spared and either the nervous system or the heart will be affected. Neurologic symptoms include numbness or tingling or weakness of isolated parts of the body. Cardiac complaints are most likely to be of an irregular heart rhythm.

Medical personnel confirm latent Lyme disease with a blood test and treat with antibiotics. The antibiotics cure the infection but some of the symptoms are due to an autoimmune response to the infection and can take months to resolve completely. Again, at this stage there is no critical time frame for the initiation of antibiotics.

Vaccine proves too problematic

A vaccine for Lyme disease existed, but is no longer available. The manufacturer took the difficult-to-administer vaccine off the market because it was used so rarely. A three-shot series given over six months established immunity, but then a patient required maintenance booster shots every two years. Compare that with the difficulty in ensuring administration of tetanus boosters every ten years! Administering Lyme boosters every two years would have posed an unprecedented challenge for local clinicians.

Neither the Massachusetts Board of Public Health nor the Centers for Disease Control endorsed use of the vaccine. Lyme disease has not been demonstrated to be lethal, and these institutions only recommend immunization for diseases that are deadly. Furthermore, the vaccine was not perfect. It did prevent latent Lyme disease but it had a significant failure rate for the prevention of acute Lyme disease.

Developing immunity

Finally, not all of us are susceptible to Lyme disease. In areas where borrelia-bearing ticks have long been common, as many as 23% of long-time residents show immunologic evidence of a previous Lyme infection but have no history of having had the disease. These people seem to have been infected and mounted a successful resistance to the organism without the aid of antibiotics and without any significant illness.

Dr. Claudia Talland currently works as a primary care internist at Acton Medical Associates. She also serves in an advisory capacity to the Carlisle Board of Health.

more on ticks see Biodiversity Corner

2002 The Carlisle Mosquito