by Lynne Bleeker
Science Teacher
NFK Consultant

Summer: school graduation, vacation, parades, and Lyme disease. What? Lyme disease? Yes, in some parts of the U.S., Lyme disease may be on people's minds as the weather warms up and people spend more time out of doors. What exactly is Lyme disease? How can you avoid getting it? Let's take a closer look at this disease.

What is Lyme Disease?


What causes Lyme Disease?

Many people think that Lyme disease is caused by ticks. However, it is actually a disease caused by a bacterium called Borrelia burgdorferi. The bacteria is transmitted to humans via tick bites, so people associate ticks with Lyme disease. This way of disease transmission is a classic example of parasitology involving several organisms:

  1. The bacterium Borrelia burgdorferi. These bacteria are found in the wild in white-footed mice and in ticks on deer.

  2. Mice and deer. Small animals are bitten by juvenile (immature) deer ticks or Western black-legged ticks. The primary types of ticks that carry Lyme disease are the Ixodes scapularis (black-legged tick) and Ixodes pacificus (Western black-legged tick). Even when the tick leaves the deer or mouse, the bacteria stay in the bodies of the tick.

  3. The ticks, Ixodes scapularis (black-legged tick) and Ixodes pacificus (Western black-legged tick). The ticks can attach themselves to humans and bite them. The ticks can then transmit the bacteria to the human.

Borrelia burgdorferi
Image courtesy of the NIAID

How common is Lyme Disease?

According to the U.S. Center for Disease Control (CDC), Lyme disease is the most common arthropod-borne disease in the U.S. More than 150,000 cases have been reported since 1982.

Data from the CDC.

Image courtesy of the NIAID

What are the symptoms of Lyme disease?

Lyme disease is rather difficult to diagnose because many of its symptoms can occur with other diseases. Typically the first and most distinctive symptom of Lyme Disease is an expanding rash which usually radiates from the site of the tick bite. The rash usually appears 1-2 weeks after the tick bite. It may be accompanied by joint pains or general achiness, chills, fever and headache. Later there may be other rashes, a stiff neck, facial palsy similar to Bell's palsy, tingling or numbness in the extremities, headache, sore throat and severe fatigue. In the late stage of untreated Lyme disease, people may experience arthritis (pain/swelling) of one or two large joints, disabling neurological disorders such as disorientation, short term memory loss, mental "fog" and numbness in the hands or feet.

What can you do to protect yourself from the disease?

If you live in or will be visiting an area where the bacterium Borrelia burgdorferi is found in wild animals, it is wise to take precautions against tick bites. Deer ticks like to hide in dark shady places such as moist ground litter in or near forests. They cannot jump or fly, but crawl onto the skin of a potential host. Once they are on the skin, they crawl up to dark protected areas such as the back of the knee, the neck, armpits, ears, etc. They then begin to pierce the skin of the host until they find a blood supply.

The best protection against Lyme disease is to avoid areas where ticks live and to check yourself for ticks after you have been outside. The good news is that even if you find a tick, if you remove it correctly before it has been there 24-36 hours (and its body is engorged with blood), you can greatly reduce your chances of getting the disease. According to the FDA and CDC, the best way to remove the tick is to use tweezers. Grasp the tick by its mouthparts where it enters your skin and pull steadily outward. DO NOT just squeeze the tick's body. Quick jerking motions and irritants may cause the head of the tick to stay inside your skin. Therefore, Lyme disease could be transmitted even after the tick's body has been removed.

If you do come down with some of the symptoms, especially if you live in an area where there is not known to be a wild population of Borrelia burgdorferi, it would be wise to talk to your physician. Let him or her know where you have been travelling and what outdoor activities you have taken part in.

How is Lyme Disease treated?

The Centers for Disease and Control and the National Institute of Allergy and Infectious Disease recommend that people with Lyme disease should be treated with antibiotics, such as doxycyline or amoxicillin (other drugs can be used with people allergic to penicillin). Physicians, guided by a patient's response to antibiotics, may recommend a course of antibiotics lasting for several weeks. Research is also underway to develop a vaccine to prevent Lyme disease.

Still, watch out for those ticks!

Chronic Lyme Disease

Some people with Lyme disease have chronic symptoms that do not respond to medication. These symptoms include fatigue, memory loss, and joint pain (arthritis). The knee is the joint most commonly affected. In treated adults, approximately 10% have chronic joint inflammation for months or years following the infection. The reason for these chronic symptoms is not known. It is unclear whether these symptoms are caused by Lyme disease or by some other cause.

Did you know?

  • Borrelia burgdorferi was named after its discoverer, Willy Burgdorfer. Brugdorfer reported in 1982 that a spirochete, a type of bacteria, found in ticks of the Ixodes genus was probably responsible for Lyme disease.

  • A 90-million-year-old tick was discovered encased in amber in a vacant lot in New Jersey. According to Science magazine, "Ticks are thought to have originated at least 100 million years ago in South America." (Reference: Science, 292 [April 13, 2001]; page 205)

  • There were 22,014 confirmed cases and 8,817 probably cases of Lyme Disease were reported to the Center for Disease Control in 2012.

For more information about Lyme disease, check out the following web sites:

  1. Lyme Disease: Ten things you always wanted to know about ticks...
  2. International Lyme and Associated Diseases Society
  3. Battling Lyme Disease - Scientific American (July 5, 2000)
  4. Lyme Disease Network
  5. Neurological Sequelae of Lyme Disease - from NINDS
  6. Lyme Disease - A Patient Guide
  7. Lyme Disease - Teacher Guide
  8. Lyme Disease and Other Tick-Borne Diseases - from NIAID
  9. Lyme Disease Education
  10. Lyme Disease Information - from the CDC


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This page was updated on May 18, 2014.