Lyme disease

What is Lyme disease?

Lyme disease is an infection caused by a bacteria transmitted through the bite of an infected tick. In Ontario, Lyme disease is spread by the bite of a black-legged tick, commonly known as a deer tick. Most humans are infected through the bite of an immature tick called a nymph. Nymphs are tiny (less than 2 mm) and difficult to see; they feed during the spring and summer months.

Adult ticks are much larger and are more likely to be discovered and removed before they have had time to transmit the bacteria. Adult blacklegged ticks are most active during late summer and fall.

Ottawa situation

Ottawa is not yet considered to be an established area for infected blacklegged ticks, however, infected blacklegged ticks can sometimes be found in this area.

Areas close to Ottawa where infected black legged tick populations are established including: Leeds-Grenville-Lanark, Brockville, and Kingston. 

Due to the closeness of these areas, Ottawa is considered at-risk for becoming an established area for infected black legged tick populations in the future.

 Most cases report being exposed outside of Ottawa.  For numbers of confirmed cases in Ottawa, see Reportable disease by year for Ottawa residents.  

There are other types of ticks which are found in the Ottawa area but do not carry Lyme disease.


Symptoms usually begin within three days to one month after being bitten by an infected tickImage of a circular, red rash that expands around the tick bite

  • circular, red rash (sometimes called a “bulls-eye” rash) that slowly expands around the tick bite
  • fatigue
  • chills
  • fever
  • headache
  • muscle and joint pain
  • swollen  lymph nodes

If you develop symptoms of Lyme disease, consult your health care provider

What do ticks look like?

Three nymphs of the blacklegged tick are shown in different stages of feeding.

Three nymphs of the blacklegged tick are shown in different stages of feeding.

This figure shows 5 female blacklegged ticks in different stages of feeding

This figure shows 5 female blacklegged ticks in different stages of feeding

What if I find a tick?

If you find a tick on you, remove it as soon as possible as the tick must be attached to your body for at least 24 hours to pass on the bacteria.

  1. Use tweezers
  2.  Grasp the tick's head as close to the skin as possible and pull slowly until the tick is removed. Do not twist or rotate the tick.  Do not use a match, lotion or anything else on the tick.
  3. Place the tick in an empty pill vial or zip-lock bag with a moistened paper towel
  4. Wash the bite site with soap and water

Get your tick tested

  • Ticks that have bitten residents can be submitted through Ottawa Public Health for testing.  As this is a surveillance and identification program only, results may not be available for a number of months.
    The case clinical management of the tick exposure is conducted by a physician
    • Call public health to set up an appointment to submit the tick at 613-580-6744.
  • Ticks retrieved from animals may be submitted to Public Health Agency of CanadaThis process does not involve Ottawa Public Health.

Avoid ticks

  • Watch for ticks from early spring to late fall every year.
  • Avoid tick habitats such as tall grass, bushes and woods. Stay in the middle of trails, if possible.
  • Do a “tick check” at the end of every day spent outdoors. Carefully inspect yourself for any ticks, starting at your ankles and moving up. Take special care around your knees, armpits and head.
  • Blacklegged ticks are very small, particularly during the nymph stage, so look carefully.
  • Check children and pets as well.
  • Wear light-colored clothing, because it is  easier to see  and remove ticks
  • Wear long pants and a long sleeved shirt.
  • Wear closed footwear and socks
  • Tuck your pants into your socks.
  • Use an insect repellent that has "DEET".  Always read and follow label directions

For further information:

Ontario Ministry of Health

Public Health Agency of Canada

Centre for Disease Control and Prevention