About Lyme Disease in Canada

Lyme disease is a complex multi-system inflammatory illness caused by the bite of a tick infected with one of several closely related species of Borrelia bacteria. It's by far the most common tick-borne illness in Canada, but it's by no means the only one.

Kids lying in fieldOur understanding of Lyme disease in Canada is in its infancy. The first breeding colony of blacklegged ticks (Ixodes scapularis) was discovered at Long Point, Ontario on the north shore of Lake Erie back in the early 1970s and by the late 1980s that colony was found to be infected with Lyme bacteria. Since that time, many more breeding colonies have been found throughout southern Canada with hotspots identified in British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, and Quebec. The remaining provinces are expected to be colonized in the near future. Every year, more Lyme-endemic regions are added to risk maps and locally acquired cases of Lyme disease have now been reported in every province.

Lyme disease is projected to spread rapidly across Canada over the coming decades and many factors are driving this expansion, including climate change, forest fragmentation, declining biodiversity and migrating birds, which are estimated to distribute as many as 175 million blacklegged ticks across Canada each spring from two distinct populations in the United States -- the Northeast (whose ticks primarily wind up in Ontario, Quebec and the Maritimes) and the Midwest (whose ticks primarily wind up in the prairie provinces) -- as well as from established colonies within Canada. Western blacklegged ticks (Ixodes pacificus) and Ixodes angustus (no common name) are the primary ticks responsible for transmitting Lyme bacteria to humans in several regions of southern British Columbia.

When I first began researching ticks and tick-borne illnesses in 2007, peer-reviewed journal articles on ticks and tick-borne illnesses by Canadian researchers were few in number. Much of what Canadians were being told about Lyme disease was borrowed from research done in the United States and it was unclear how -- or even if -- that research applied to the situation in Canada. To make things more challenging, the limited research being done in this country didn't appear to be finding its way to doctor's offices, public health units, or the general public, something that resulted in a disturbing disconnect between researchers and just about everyone else.

In the past decade, an increasing number of researchers in every province (and representing an impressive array of disciplines) have started applying their expertise to ticks and tick-borne illnesses. As a result, we are collectively learning an ever increasing amount about the unique situation we face here in Canada. But we're still a long way from being able to make definitive statements about a great many aspects of Lyme disease in this country.

This website's goal is to catalogue Canadian research on ticks and tick-borne illnesses so that anyone who wants to educate themselves on the subject can find the information they're looking for in one convenient place. Please note that many aspects of tick-borne illnesses are currently either under-researched or not being researched at all in this country, so if you can't find what you are looking for, there is a good chance it does not yet exist.

Lyme Disease in Canada's Vanessa Farnsworth speaks with host Wayne MacPhail about the complicated role climate change plays in the tick invasion of Canada on the Harrowsmith Radio Podcast.

Lecture: Lyme Disease in Nature

Projected Spread of Blacklegged Ticks

Book Trailer: Rain on a Distant Roof