Risk of Lyme disease to Canadians
Learn about the risks of getting Lyme disease and where in Canada you are most at risk.
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What is the risk to Canadians?
The risk of getting a tick bite starts when the weather warms up in the spring, through until the fall. Ticks can also be active in the winter, if the winter is mild and there is not much snow. However, the greatest risk occurs during the spring and summer months.
Blacklegged ticks are most often found in forests, wooded areas, shrubs, tall grass and leaf piles. Because tick populations are spreading, it is possible to be bitten outside of these areas.
Who is most at risk?
If you work outdoors or participate in outdoor activities, you may be at a greater risk for tick bites. When engaging in the following activities, you should take precautions against tick bites:
Where in Canada are you at risk?
The greatest risk of acquiring Lyme disease occurs where populations of ticks that carry the bacteria (B. burgdorferi) that causes Lyme disease, have become established.
Surveillance in recent years indicates that populations of blacklegged ticks are spreading in eastern and central Canada. Areas in Canada where there is evidence for the occurrence of reproducing populations of known tick vector species (particularly blacklegged ticks and western blacklegged ticks) and the likely transmission of B. burgdorferi are called: Lyme disease risk areas (See the Lyme Disease risk areas map for more details).
The occurrence of these risk areas is determined by tick surveillance and risk assessment methods described in detail in the Lyme disease case definition.
Following are the currently identified risk areas in Canada:
In British Columbia (B.C.), currently identified risk areas for Lyme disease are:
- Vancouver Island
- Southern Mainland
- Coast of British Columbia facing Vancouver Island
- 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
In Manitoba, currently identified risk areas for Lyme disease are:
- 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
- parts of southern Manitoba along the border with the United States from south of Brandon to Lake of the Woods
- some areas around Winnipeg
- North of the community of McDonald (near Delta Beach)
- Winnipeg Beach
- southeast of Treherne
- Tourond (southeast of Niverville)
In Ontario, currently identified risk 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
- Kingston and surrounding area
- 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
In Quebec, currently identified risk areas for Lyme disease are:
- Montérégie (south of Québec)
- southwest of Mauricie et Centre-du-Québec
- north and west of Estrie
In New Brunswick, currently identified risk areas for Lyme disease are:
- Areas of Charlotte County
- Areas of Saint John County
- Areas of Kings County
- Areas of Albert County
- Areas of Westmorland County
In Nova Scotia, currently identified risk areas for Lyme disease are:
- Areas of Yarmouth County
- Areas of Pictou County
- Areas of Lunenburg County
- Areas of Queens County
- Areas of Halifax Regional Municipality
- Areas of Shelburne County
As ticks attach themselves to birds, they can be found in areas across Canada, other than those noted above. The Public Health Agency of Canada, in partnership with provincial and territorial public health organizations is conducting ongoing surveillance to help 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 risk areas in Canada - Text equivalent
See the Surveillance page for more information on Lyme disease surveillance activities and reported human cases in Canada.
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