Saskatchewan sees increase in ticks that can carry Lyme disease

A species of tick originally considered rare in Saskatchewan is increasing in number.

Scientists have seen an increase in the number of black-legged ticks, a species known for carrying Lyme disease.

Ixodes scapularis, also known as the deer tick or black-legged tick, is a hard-bodied tick typically found in the eastern and northern midwest of the United States as well as in southeastern Canada.

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The black-legged tick has a two-year lifecycle, during which it will pass through three different stages: Larva, nymph and adult. The tick must take a blood meal before each transition.

Deer are the preferred host of the adult deer tick, but it is also known to feed on small rodents. A female black-legged tick, once attached to its host, will drink its blood for four to five days, unlatch itself, and then lay on the forest floor over winter. The following spring, the female will lay several hundred eggs.

Parasitology specialist and lab manager Maria Jarque dragging for ticks. (Photo courtesy of Emily Jenkins)

Emily Jenkins, a professor of veterinary microbiology at the Western College of Veterinary Medicine in Saskatoon, said the black-legged tick was at one point considered to be very rare.

“We had an unusual year in 2023. We had a lot more reports using eTick of black-legged ticks on people and pets than we usually do,” Jenkins told guest host Taylor MacPherson on The Evan Bray Show on Tuesday.

“Then the big news for us was that we found for the first time ever dragging in the environment in this province evidence that there were free-ranging black-legged ticks out there in the environment — not very many, but it was pretty big news for us.”

Tick-dragging refers to when a researcher drags a one-square-metre strip of white cloth mounted on a pole that is tied to a length of rope. The researcher will drag the cloth behind them as they walk through different terrain, such as low-lying bushes and grass, that they believe to be an area with a high tick population.

Tick-dragging is one of many methods researchers use to gather wild ticks for study, mainly due to its ability to cover a large area.

“For years and years and years, we have only ever found many American dog ticks and a few of the Rocky Mountain wood ticks, both of which we kind of expect to see here. They’re homegrown,” Jenkins said. “In that whole time, we’ve never picked up black-legged ticks, and this was the first time in 2023, in June, that we picked up loose black-legged ticks in the environment.”

She said the growing number of these ticks is concerning.

“Black-legged ticks are a competent vector and can transmit Lyme disease as well as some other fairly nasty pathogens, so that’s why we’re a lot more worried about that one than our homegrown ticks,” said Jenkins.

“The good news is that all the things people are doing to protect themselves against ticks — which most Saskatchewan folks are pretty good at now — are going to be protective against picking up the black-legged ticks as well.

“The only differences are that if you’re doing tick checks, you need to have a bit of a different search image. The black-legged ticks are smaller; particularly the nymphs are almost microscopic, it seems, and they are a lot harder to pick up.

“The other difference is that black-legged ticks are active much later into the year, so our peak season where we tend to hear about people getting these ticks is October and November, which is not when people typically think of tick season.”

The species usually hitches rides on migratory birds or comes with pets from outside the province.