Lyme disease is the most common vector-borne disease in North America. The disease was first recognised in Connecticut in 1975, and is caused by a bacteria called Borrelia burgdorferi. It is transmitted to humans through the bite of an infectious blacklegged tick.
Blacklegged ticks (also known as deer ticks) are widespread throughout Canada, due to tick larvae and nymphs attaching themselves to migratory birds. Bird-borne ticks thus create the possibility of infectious tick bites almost anywhere in Canada.