Lyme disease is a potentially serious infection that you can get if you’re bitten by an infected blacklegged tick (also called a deer tick).

Not all blacklegged ticks carry the bacteria that causes Lyme disease, and not everyone who is bitten by an infected tick will develop signs and symptoms of Lyme disease.

What blacklegged ticks look like

Blacklegged ticks are small and hard to see. They attach themselves to humans and animals and feed on their blood. They can range in size depending on how long they have been feeding.

You can find out if it’s a blacklegged tick by:

5 ticks on a ruler and surrounding a dime. They range in size from about 3 millimeters long to about half the size of the dime.

Adult female blacklegged tick at various stages of feeding. Photo: Government of Canada

Where blacklegged ticks live

We continue to track where infected – and uninfected – blacklegged ticks are being found.

Public Health Ontario’s Lyme disease page has a map (called “Ontario Lyme disease estimated risk areas map, 2023”) that shows areas in Ontario where they estimate you are more likely to find blacklegged ticks.

Blacklegged ticks are spreading to new areas of the province because of climate change. They can also spread by traveling on birds and deer. While the probability is low, it is possible to find an infected tick almost anywhere in Ontario.

Ticks are most active in spring and summer, but can be found at any time of the year when the temperature is above freezing.

How to avoid getting a tick bite

You might be at risk if you live, work in, or visit a wooded area, or an area with tall grasses and bushes (including city gardens and parks).

You may also be at risk if you are involved in outdoor activities such as hiking, camping and gardening.

You may be bitten by a tick and not even know it.

Here’s what you can do to avoid getting a tick bite.

Cover up


  • light-coloured clothing, so it’s easier to see ticks
  • closed-toed shoes
  • long-sleeved shirts
  • long pants, tucked into your socks
  • special clothing designed to repel ticks

Use insect repellent

Use an insect repellent, or bug spray, that says “DEET” or “icaridin” on it. Put it on your clothes and exposed skin. Always read the label for directions on how to use it.

Put clothes in the dryer

Kill any ticks that might be on your clothing by putting your clothes in a dryer on high heat for at least 10 minutes before washing them.

Check yourself and your children

After being outdoors, check for ticks on yourself and your children. Look:

  • behind your knees
  • on your head
  • in your belly button
  • in your groin area
  • in your underarm area
  • on the back of your body – use a mirror, or ask someone to check for you

It’s a good idea to have a shower as soon as you can to wash off any ticks.

Check your pets for ticks

After being outdoors, check your pets’ skin and remove any ticks you find.

Ask your veterinarian about options to help keep ticks off your pets.

Maintain your property

You can help keep blacklegged ticks away from your property by:

  • keeping grass mowed short
  • trimming bushes and tree branches to let in sunlight (ticks avoid hot, dry locations)
  • creating a border of gravel or woodchips one metre or wider around your yard if you’re next to a wooded area, or an area with tall grasses
  • removing leaf litter, brush and weeds at the edge of the lawn and from stone walls and wood piles
  • moving children’s swing sets, playground equipment and sandboxes away from wooded areas
    • consider placing equipment on a woodchip or mulch foundation

How to remove a tick

Removing a tick is the same for humans and animals. It’s important you do not crush or damage the tick because it could cause Lyme bacteria to pass from the tick into your bloodstream.

  1. Use fine-tipped tweezers and grasp the tick as close to your skin as possible.
    • Do not use a lit match or cigarette, nail polish or nail polish remover, petroleum jelly (for example, Vaseline), liquid soap or kerosene to remove the tick.
  2. Pull the tick straight out, gently but firmly.
    • Do not jerk or twist the tweezers while pulling the tick out.
    • Do not squeeze the tick – you might crush it.
A drawing of a tick sticking out from skin, attached at its mouth. Tweezer arms grab it horizontal to the skin and flat against to top and bottom of its body. An arrow indicates you are to pull the tick straight up and out.

How to remove a tick.

  1. Once you have removed a tick, wash your skin with soap and water and then disinfect your skin and your hands with rubbing alcohol or an iodine swab.
  2. Before disposing of the tick, call or check the website of your local public health unit to get advice on how to identify the tick. You can also submit a photo of the tick to for identification.

Tick testing

Tick testing is only done with ticks collected by your local public health unit using a method called tick dragging. These test results are used to monitor where infected and uninfected ticks live.

Tick testing is not used to diagnose Lyme disease in humans.

Lyme disease signs and symptoms

Most symptoms of Lyme disease in humans usually appear between three and 30 days after a bite from an infected blacklegged tick.

You should contact your local public health unit or speak to a health care professional right away if you have been somewhere that ticks might live and experience any of the following symptoms:

  • rash
    • a bull’s-eye rash (a red patch on the skin that is usually round or oval and more than 5 cm that spreads outwards and is getting bigger
    • a bruise-like rash (usually on darker skin tones)
    • another type of unusual rash

A person’s upper arm shows a red patch at the site of the tick bite, inside a larger red ring.  Four raised pink patches on someone’s stomach.

  • fever
  • chills
  • headache
  • stiff neck
  • muscle aches and joint pains
  • fatigue (more tired than usual)
  • swollen lymph nodes
  • spasms, numbness or tingling
  • facial paralysis

If not treated, Lyme disease can make you feel tired and weak and, if it gets really bad, it can even harm your heart, nerves, liver and joints. Symptoms from untreated Lyme disease can last years and include recurring arthritis and neurological problems, numbness, paralysis and, in very rare cases, death.

Lyme disease diagnosis and treatment

Your health care provider may diagnose you with Lyme disease depending on your signs, symptoms and risk factors. Laboratory testing is not always required to diagnose and treat Lyme disease infection.

Most cases of Lyme disease can be treated successfully with antibiotics.

Additional resources

Download fact sheet
Download poster