Surveillance of Lyme disease

Learn about surveillance for Lyme disease in Canada. Also find out how many Lyme disease cases in humans have been reported.

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Canada's surveillance of Lyme disease

The Government of Canada engages in surveillance activities to capture the number of people with Lyme disease and the locations of tick populations. It does this in partnership with:

  • provincial and territorial public health organizations
  • health authorities
  • other experts

Surveillance is done in 3 ways:

  • reporting of human Lyme disease cases by Provincial and Territorial public health organisations
  • voluntary submission of ticks collected from people and pets by doctors and vets (known as passive tick surveillance)
  • studies in the field to collect ticks from the environment (knows as active  tick surveillance)

Locations where both ticks and Lyme disease have been confirmed over multiple years of active field surveillance are called known endemic areas. Confirmation is based on:

  • active field surveillance revealed the presence of all life stages of the ticks at multiple visits over more than one year
  • detection of the Lyme disease pathogen in ticks or animals collected from the site

A suspected endemic area is the same as an endemic area except that the ticks and Lyme disease pathogen have not yet been found in more than one year.

Locations where tick vectors of Lyme disease have been detected by active surveillance are considered to be risk areas. (See map.)  The presence of Borrelia burgdorferi does not need to be confirmed in samples (tick or animal) for an area to be considered a risk area.

Through surveillance, the Government can identify trends in the numbers of Lyme disease cases and where in Canada there is a risk of getting Lyme disease. The greatest risk occurs where ticks that carry the Lyme disease-causing agent are found. Surveillance in recent years indicates that established populations of blacklegged ticks are spreading. However, while tick numbers are increasing in eastern and central Canada, the British Columbia Ministry of Health indicates that this is not the case in British Columbia.

British Columbia

In British Columbia (B.C.), known and suspect endemic areas for Lyme disease are found on:

  • Vancouver Island
  • Southern Mainland
  • Coast of British Columbia facing Vancouver Island

Risk areas include:

  • River valleys across the southern part of the province

The B.C. Ministry of Health has reported a plateau in the number of infected tick populations in the past decade. This contrasts to the spread seen in the rest of Canada. This is due to:

  • the western blacklegged ticks spread into B.C. much earlier than the blacklegged ticks found in central and eastern Canada
  • far fewer western blacklegged ticks being infected with the Lyme disease bacterium than blacklegged ticks found in central and eastern Canada

Manitoba

In Manitoba, known or suspect areas for Lyme disease are the:

  • west side of Lake of the Woods
  • Pembina escarpment, including Pembina Valley Provincial Park
  • St. Malo region
  • Vita/Arbakka region, including the Roseau River
  • Beaudry Provincial Park
  • Assiniboine River
  • areas next to the Agassiz and Sandilands provincial forests

Risk areas include:

  • parts of southern Manitoba along the border with the United States from south of Brandon to Lake of the Woods
  • some areas around Winnipeg

Ontario

In Ontario, known endemic areas for Lyme disease are:

  • Point Pelee National Park
  • Rondeau and Turkey Point provincial parks
  • Long Point peninsula, including Long Point Provincial Park and the national wildlife area
  • Wainfleet bog near Welland on the Niagara peninsula
  • Prince Edward Point
  • parts of Thousand Islands National Park

Risk areas include:

  • locations around Kingston
  • along the St. Lawrence Valley to the border with Quebec and northeast towards Ottawa
  • western Ontario in the region of Lake of the Woods
  • Pinery Park on the shore of Lake Huron
  • Rouge Valley region of eastern Toronto

Quebec

In Quebec, known endemic areas for Lyme disease are found in:

  • Montérégie (south of Québec)

Risk areas include:

  • much of Montérégie
  • parts of Estrie
  • parts of central Québec

New Brunswick

In New Brunswick, known endemic areas for Lyme disease are:

  • the Millidgeville area of Saint John
  • North Head on Grand Manan Island

Nova Scotia

In Nova Scotia, known endemic areas for Lyme disease are:

  • Halifax Regional Municipality
  • areas in the counties of Lunenburg, Shelburne, Yarmouth, Pictou and Queens

Possible risk areas are locations around these endemic areas.

Other areas

As ticks attach themselves to birds, they can be found in areas across Canada, other than those noted above. Ongoing surveillance by the Government helps identify the spread of blacklegged tick populations in Canada.

Because localized tick populations can spread, it is difficult to define the geographic limits of a population. Canadians living or visiting areas next to established tick populations are advised to take precautions against ticks.

Lyme disease became nationally notifiable in 2009. Since then, provincial and territorial public health authorities provide human case data to the Canadian Notifiable Disease Surveillance System (CNDSS).

As well, some provinces provide more detailed data on Lyme disease to inform the enhanced surveillance program.  Detailed data helps better identify:

  • changing trends in incidence
  • the risk to the population
  • the types of clinical disease (which informs clinician-based LD diagnosis and reporting)..

Reported number of Lyme disease cases

The Government currently has data for Lyme disease cases reported between 2009 and 2013:

  • 2009: 128 cases
  • 2010: 132 cases
  • 2011: 258 cases
  • 2012: 315 cases
  • 2013: 682 cases
  • 2014: currently validating reports from provinces and territories

These numbers may change slightly should updated information come in from provincial or territorial public health organizations.

The true number of cases is expected to be higher, as cases are captured only if acquired in known endemic areas. Health care professionals in Canada have a critical role to play in identifying confirmed and probable cases of Lyme disease. See the Information for health professionals on Lyme disease page for more information on:

  • clinical manifestations
  • laboratory testing
  • treatment
  • prevention
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