Lyme disease

Lyme disease is a serious illness caused by the bite of an infected blacklegged tick. Ticks are small, ranging from the size of a poppy seed to a pea. The size of the tick varies depending on its age and whether it has fed recently. The bite is usually painless so you may not know that you have been bitten. It is important to be on the lookout for ticks and the symptoms of Lyme disease.

Lyme disease is found in Europe, Asia, and in many parts of North America. The risk of getting Lyme disease is increasing in Canada. As such, Canadians are encouraged to take preventive measures to  reduce their risk when spending time in areas where there may be ticks.

On this page:

Causes of Lyme disease

Lyme disease is the most common tick-borne disease in Canada. It is caused by the bite of blacklegged ticks infected with Lyme disease. If untreated, Lyme disease can cause serious illness with severe symptoms. It is easy to prevent Lyme disease and when caught early, it is easy to treat.

It is important to note that people cannot spread Lyme disease to each other. Although pets, particularly dogs, can contract Lyme disease, there is no evidence that they can spread the infection directly to people. However, pets can carry infected ticks into homes and yards.

What to do if you are bitten by a blacklegged tick

Removing ticks within 24-36 hours usually prevents infection. Using clean tweezers, grasp the head as close to the skin as possible and slowly pull straight out. Afterwards, wash the bite site with soap and water or disinfect with alcohol or hand sanitizer. If mouthparts break off and remain in the skin, remove them with tweezers. If you are unable to remove them easily, leave them alone and let the skin heal.

If possible, save the tick in a zip-lock bag and record the date of the bite. If you develop symptoms of Lyme disease in the weeks after being bitten, contact your health care provider right away. Bring the tick with you to your medical appointment, as it may help the doctor in assessing your illness.

Symptoms of Lyme disease

Some people may have no symptoms at all. Others may suffer severe symptoms, but not for weeks after the bite. As such, they may not associate the illness with a tick bite. Lyme disease signs and symptoms can include one or a combination of the following, with varying degrees of severity:

  • fatigue
  • fever or chills
  • headache
  • spasms, or weakness
  • numbness or tingling
  • swollen lymph nodes
  • skin rash
  • cognitive dysfunction (brain fog), dizziness
  • nervous system disorders
  • arthritis and arthritic symptoms (muscle and joint pain)
  • abnormal heartbeat

Untreated, symptoms can last months to years. More serious symptoms include recurring arthritis (muscle and joint pain), nervous system and/or neurological problems, numbness and/or paralysis (unable to move parts of the body). Although not common, fatalities from Lyme disease have been reported.

What to do if you have symptoms

If you develop symptoms of Lyme disease in the weeks after a tick bite, contact your healthcare provider right away. The earlier you receive a diagnosis, the greater your chances are of a successful treatment. If you saved the tick that bit you, bring it with you to your medical appointment. It may help the doctor in assessing your illness.

Risks of getting Lyme disease

The risk to Canadians

The risk of getting a tick bite starts when the weather warms up in the spring, through till the fall. Ticks might also be active in the winter, if the winter is mild and has little snow. However, the greatest risk of contracting Lyme disease is during the spring and summer months.

Blacklegged ticks are most often found in forests and the overgrown areas between the woods and open spaces. It is important to note that as tick populations are spreading, it is possible to be bitten outside of these locations. The Public Health Agency of Canada works with provinces and territories to identify where populations of infected blacklegged ticks are established or spreading. These areas include:

  • southern British Columbia
  • southeastern and south-central Manitoba
  • southern and eastern Ontario
  • southern Quebec
  • southern New Brunswick and Grand Manan Island
  • parts of Nova Scotia

Ticks don't move far by themselves. But they can attach themselves to migratory birds, and fall off far from their original location. Infected ticks can therefore be found in other areas across Canada, and not just in the confirmed areas noted above. Ongoing surveillance will show where blacklegged tick populations are in Canada.

Who is most at risk?

If you work outdoors or participate in outdoor activities like golfing, hunting, camping, fishing and hiking, you may be at greater risk for tick bites.

Treatment for Lyme disease

Consult a health care provider as soon as possible if you think you may have Lyme disease. The sooner you get treatment, the more rapid will be your recovery.

Diagnosing Lyme disease

Sometimes, diagnosing Lyme disease can be difficult because symptoms vary from person to person, and can be similar to other illnesses. Your healthcare provider will likely:

  • examine your symptoms
  • determine if you were potentially exposed to Lyme-infected blacklegged ticks by asking about your recent activities
  • request (if necessary) laboratory blood testing to support a clinical diagnosis

Your symptoms are an important part of getting a diagnosis. Lab results may not always detect Lyme disease, especially if it is in the early stages. Lab results might also be affected if you were recently on antibiotics. Blood test results are clearer when the disease is further along.

Treating Lyme disease

Most cases of Lyme disease can be effectively treated with two to four weeks of antibiotics. Depending on symptoms, and when you were diagnosed, you may require a longer course of antibiotics.

Some people experience symptoms that continue more than six months after treatment. Research continues into the causes of these persistent symptoms and possible treatment methods.

Prevent Lyme-infected tick bites

The best way to protect yourself from Lyme disease is to prevent tick bites. Protect yourself if you venture into forested or overgrown areas:

  • wear closed-toe shoes, long-sleeved shirts and pants
  • pull your socks over your pant legs
  • wear light coloured clothes to spot ticks easier
  • use insect repellent that contains DEET (common active ingredient to keep biting bugs away) or Icaridin (always read and follow label directions)
  • shower or bathe within two hours of being outdoors to wash away loose ticks
  • do daily "full body" checks for ticks on yourself, your children and pets

Ticks attach themselves to the skin and removing them within 24-36 hours usually prevents infection.

How to reduce tick habitats near your home

Keep your lawn and yard well maintained to prevent ticks from living near your home:

  • keep the grass mowed
  • remove leaf litter, brush and weeds at the edge of the lawn and around stonewalls and woodpiles
  • discourage rodent activity by cleaning up and sealing stonewalls and small openings around the home
  • move firewood piles and bird feeders away from the house
  • keep your pets, particularly dogs, out of the woods and talk to your vet about tick repellents for your pets
  • move children's swing sets and sand boxes away from the woodland edge and place them on a woodchip or mulch foundation
  • adopt hard landscape practices (using hard materials like stone and metals instead of soft materials like soil for planting)
Date modified: