Climate change is causing a migration of ticks to new regions in southern Canada, with experts predicting a continuous expansion of these blood-sucking pests. Ticks carrying diseases were not a major concern in Canada until the 1990s, but various species are moving north from the United States at a pace of 35 to 55 kilometers annually. According to Katie Clow, an assistant professor at the University of Guelph, areas in southern Canada currently free of ticks are expected to witness their emergence in the next decade.
The spread of Lyme disease, transmitted by blacklegged ticks, was first documented in southern Ontario in 1989. Since then, these ticks, also capable of transmitting the Powassan virus in rare cases, have been identified in all other Canadian provinces, including Alberta and Saskatchewan. Health Canada reports that there are over 40 tick species present in Canada, some of which pose significant health risks.
Research indicates a notable increase in Lyme disease cases in Canada, with the Public Health Agency of Canada reporting 7,105 cases in 2025 compared to 144 cases in 2009. The disease, if untreated, can lead to severe complications affecting the joints, heart, and nervous system. Clow highlights the concern around blacklegged ticks during their nymph stage, which peaks in June and early July due to their small size and difficulty in detection.
The growth of tick populations is attributed to climate change trends over recent decades. The warming climate has created more favorable conditions for ticks, enabling their survival and reproduction even during winter months. As a result, some tick species are now active year-round, especially in suburban areas where forest fragmentation has led to increased deer and rodent populations.
Experts emphasize the importance of precautionary measures for outdoor activities to minimize tick exposure. These measures include wearing protective clothing, using insect repellent, checking for ticks after being outdoors, and maintaining clear pathways on properties. Researchers stress that tick encounters are likely to become more common, making it essential for Canadians to adapt their habits to reduce the risk of tick-borne diseases.