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Guide Health: Exposed to Lyme disease

The number of diagnosed cases in Canada is climbing, and so is the geographic area at risk

The black-legged, or deer tick, is known to carry Lyme disease.

One of the hazards of outdoor activity is exposure to insects, and one of the insect-like species out there is the black-legged or deer tick (ixodid tick), which can carry Lyme disease. The name originates from Old Lyme, Connecticut, the place where the disease was first identified in the late 1980s.

Recently, the incidence of Lyme disease has seemed to skyrocket with infections being identified from New Brunswick and Nova Scotia all the way across to Vancouver Island. At one time the infections seemed to occur mainly in the central Prairies, Ontario, and Quebec.

It is unclear why there has been such a spread, but theories include infected ticks “hitchhiking” rides on migrating birds, increasing numbers of deer and mice, more people living in wooded areas, the tick adapting to other animals like raccoons and squirrels, and of course improved diagnosis. In 2017 about 1,500 cases were identified; preliminary 2018 numbers are higher.

The disease is not caused by the tick itself, but rather a micro-organism, specifically a bacterium known as Borrelia burgdorferi, which the tick transmits from another animal to you.

The tick is much smaller than the usual wood or American dog tick that you usually see. It is about two to three millimetres, which is the size of a poppy seed or about the size of a typewriter comma.

Lyme disease has three stages. Anywhere up to several days after you have been bitten, a characteristic “bull’s eye” bite mark appears. Because the tick is so small, you may not remember being bitten and may not connect the rash with Lyme disease. However, other symptoms like headache, neck stiffness and fever may help you identify the disease.

During the second and third stages, the bacterium spreads through your body causing muscle pain, joint stiffness and fatigue. In all three stages, the antibiotic tetracycline is effective in stopping the infection.

Unfortunately, Lyme disease is difficult to diagnose because the symptoms can be mistaken for other conditions and in some instances the symptoms are mild which means you ignore them.

Ideally, avoiding wooded areas will reduce your chances of coming in contact with ticks, (including the more common wood tick) but that may not be possible. Ideally, too, if you do need to be out in wooded areas, you should wear long pants, long sleeves, shoes, and socks.

As well, tuck your pant legs into your socks and your shirt into your pants. Then, when you go indoors, wash and dry your clothing immediately to remove any ticks.

If you wear lighter-coloured clothing the ticks may be easier to spot. And of course check your skin for ticks. Use a magnifying glass and a mirror to check all your skin.

Ticks like moist, darker wooded areas, so if you walk in the centre of trails and avoid brush you will reduce your chances of picking up a tick. A tick needs about 24 hours in order to transmit the infection, thus you will have some time.

And, remember Lyme disease cannot be transmitted from person to person, only from the animal reservoir to the tick, then to you.

About the author


Marie Berry is a lawyer/pharmacist interested in health and education.



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