Recent expansion of black-legged ticks, Ixodes scapularis, into the Thunder Bay region: Implications and putative role of climate change

Abstract

The distribution of Ixodes scapularis is increasing in Ontario, thereby increasing the risk of contracting Lyme disease. Climate change is a likely factor in the northward expansion of I. scapularis populations. Here, I explored published studies, interviewed professionals, and performed literature reviews to answer whether climate change is the primary cause of the expansion of I. scapularis populations in Ontario, and why they are now more frequently seen in Northwestern Ontario. Climate change was determined to be a cofactor in the expansion of I. scapularis range; mobile host species are increasing the rate at which black-legged ticks are expanding. I. scapularis is capable of surviving in new locations, provided there is suitable habitat and a sufficient number of hosts. It is predicted that I. scapularis will increase its range in Ontario by 46 km/year over the next decade. Increasing I. scapularis populations across Canada increases the percentage of black-legged ticks carrying the bacterium Borrelia burgdorferi, that causes Lyme disease. This will ultimately increase the risk of Lyme disease to all.