Lyme disease: Monitoring

On this page

• Monitoring of Lyme disease in Canada
• Monitoring of human cases
• Lyme disease risk areas
• Publications

Monitoring of Lyme disease in Canada

Canada monitors Lyme disease to:

• keep track of the number of human cases of Lyme disease
• identify areas where blacklegged and western blacklegged tick populations may be emerging
• identify the areas where people are most at risk of Lyme disease

To get as much information as possible, we work with:

• provincial and territorial public health authorities
• researchers and academics

Learn more about:

• Provincial and territorial public health authorities

Monitoring of human cases

Monitoring of human cases is based on reporting of Lyme disease cases by provincial and territorial public health authorities.

Between 2009 and 2023, provincial public health units have reported 19,983 human cases of Lyme disease across Canada.

Reported cases of Lyme disease include those that are locally-acquired and travel-related. The 2016 to 2023 Lyme disease cases are reported based on the 2016 Lyme disease case definition. There's underreporting because some cases are undetected or not reported. In addition, annual case counts fluctuate due to a combination of factors including:

• public health prevention efforts
• variations in weather affecting tick activity
• variations in human activity such as time spent outdoors or healthcare-seeking behaviors

All 10 provinces voluntarily provided data over the 14-year period. Territories haven't reported any cases to the Public Health Agency of Canada since Lyme disease became nationally notifiable in 2009.

The 2023 national preliminary case count underestimates the final case count for 2023. Two provinces haven't reported preliminary Lyme disease case counts. Lyme disease cases reported by Nova Scotia are excluded from the preliminary national case count. Nova Scotia has recently revised its Lyme disease provincial case definition and it no longer aligns with the 2016 Lyme disease national case definition.

Lyme disease risk areas

Blacklegged ticks are spreading to new areas in Canada in part due to climate change. They can also spread by travelling on birds and deer. You can sometimes find blacklegged ticks in areas outside of where they're known to live.

Ticks can be active whenever the temperature is consistently above freezing and the ground isn't covered by snow. You're most likely to encounter ticks during the spring, summer and fall. However, when conditions are favourable, ticks can be active at any time of the year. The best way to prevent Lyme disease is to protect yourself against tick bites. Always take precautions against tick bites when you're in wooded or grassy areas.

The Public Health Agency of Canada, in collaboration with provincial and territorial public health authorities and partners, uses tick surveillance data and reported Lyme disease cases to identify areas where:

• tick populations may be emerging
• people are most at risk of Lyme disease

Learn more about:

• Ticks in Canada
• How to prevent tick bites

Check if you're in a risk area. Enter the first 3 characters of your postal code or municipality in the filter field below.

Use our interactive map with your postal code, municipality or province to check if you're in a risk area.

Lyme disease risk areas map

The map in figure 1 displays areas where people are most at risk of Lyme disease.

Figure 1: Text description

This figure contains 5 cross-sections which display locations where the risk:

• from tick bites is known to occur
• for Lyme disease is possible

Circled hatched areas are locations where tick risk is known and are called risk areas.

Cross-section 1: Southern Manitoba and Western Ontario

Risk areas can be found stretching:

• from the Ontario border west to Turtle Mountain Provincial Park
• from the U.S. border extending to the south shores of Lake Manitoba, Lake Winnipeg and into southern parts of the Interlake

Cross-section 2: Southern Ontario

Risk areas can be found along the north shores of Lake Erie and Lake Ontario, and on the south shore of Lake Huron.

Cross-section 3: Southeastern Ontario and Southern Quebec

Risk areas can be found around Kingston in the Saint Lawrence valley that extend northeast towards Ottawa, locations covering:

• much of Montérégie
• parts of Outaouais, Estrie and Centre du Québec in the south of Québec

Cross-section 4: Maritime provinces

In New Brunswick, risk areas can be found in the counties of:

• York
• Charlotte
• Sunbury
• Queens
• Saint John
• Kings
• Albert
• Westmorland
• Kent
• Carleton

All of Nova Scotia is found to be a risk area.

Cross-section 5: Southern British Columbia

Risk areas can be found in:

• much of Vancouver Island and the coast of British Columbia facing Vancouver Island
• river valleys across southern British Columbia

Publications

• 2022

  • Lyme disease surveillance in Canada: Annual edition 2022
  • Lyme disease surveillance in Canada: Annual edition 2022 (infographic)

• 2021

  • Lyme disease surveillance in Canada: Annual edition 2021
  • Lyme disease surveillance in Canada: Annual edition 2021 (infographic)

• 2020

  • Lyme disease surveillance in Canada: Annual edition 2020
  • Lyme disease surveillance in Canada: Annual edition 2020 (infographic)

• 2019

  • Lyme disease surveillance in Canada: Annual edition 2019
  • Lyme disease surveillance in Canada: Annual edition 2019 (infographic)
  • Surveillance for Lyme disease in Canada: 2009 to 2019
  • Lyme disease surveillance in Canada: 2009 to 2019 (infographic)

• 2018

  • Lyme disease surveillance in Canada: Annual edition 2018
  • Lyme disease surveillance in Canada: Annual edition 2018 (infographic)