Of the roughly 40 tick species known to make their home in Canada, there are nine that are capable of transmitting bacteria, viruses, and/or protozoa to humans and domestic animals. Non-infectious secretions from the salivary glands of some species can also cause paralysis, allergic reactions and/or immune system suppression.

It occurred to me recently that although I frequently make reference to Canada's ticks, nowhere do I actually talk about the different types of ticks we have in this country and what impact each one can have on human health. I’d like to change that with a series of blog posts, each one focussing on a single tick species that currently makes its home in Canada and that has been proven to (or reasonably could) transmit pathogens to humans.

Please keep in mind that new tick-borne pathogens are being discovered all the time, so this list will likely need some updating in the coming years. Of particular note, researchers have isolated several types of rickettsia bacteria from multiple species of ticks in many locations across Canada. So far these newly discovered species haven't been proven to cause human illness, but that could very well change as more is learned.

First up: Rocky Mountain Wood Tick (Dermacentor andersoni)

Photo: CDC / Dr. Christopher Paddock