Ontario's tick numbers spike, hotspots popping up in new areas

Public Health Ontario is mapping at-risk areas for Lyme disease in 2019 after a high number in 2017.

Researchers are studying data to find out where ticks are and where they are spreading.

"Initially, these risk areas were located along the north shore of Lake Erie, and along the north shore of the St. Lawrence seaway," said Public Health Ontario entomologist MarkNelder.

However, there arenew spots popping up in northwestern Ontario, Hamilton and Simcoe. Aside from natural expansion, Nelder said climate change could have to do with the spread, due to the temperatures becoming warmer.

Tick ecology

According to Katie Clow, veterinarian and researcher at the University of Guelph who studies ticks, looking at tick ecology is one way of guessing where they might go.

For blacklegged ticks, which is the species to blame for Lyme disease, they like forests, warm temperatures and a good host population, like small mammals and white-tailed deer.

"If a population is just establishing, the density of the ticks in an area can be quite low, and it can be harder to detect them," she said.

The way they can be counted in an area is having researchers dress in white suits then drag flannel blankets through the woods to collect them, Clow added.

Some people think they die off when it gets cold, but she said ticks are actually not that affected by cold winter, if they have access to an insulated area in a forest, especially with snow cover.

City-dwellers need not to worry too much, unless they like to visit forested or brushy areas.

And in places like Point Pelee and Rondeau Park in southwestern Ontario, Clow said one in three to four ticks could be carrying Lyme disease.

"The risk is high enough that you really do need to pay attention and make sure that you're doing a tick check after being out in that area."