Tick season is back. How to stay safe around these risky bloodsuckers

Thanks to warming winters and milder temperatures, ticks are thriving in more parts of the country than ever before — bringing the risk of tick-borne illnesses like Lyme disease.

As Canadians flock outdoors for hiking, gardening and sunshine this spring, an unwelcome guest is making its seasonal return: ticks.

Thanks to warming winters and milder temperatures, ticks are thriving in more parts of the country than ever before — bringing a growing risk of tick-borne illnesses like Lyme disease.

Black-legged ticks, the species responsible for most Lyme disease cases in Canada, are expanding their range rapidly and are now found in parts of every southern province. This spread is closely tied to climate change, which allows ticks to survive winter and move into once-too-cold regions, putting more people and pets at risk.

Although there are more than 40 tick species in Canada, the most common one is the black-legged tick, also known as the deer tick, and its numbers are on the rise. These ticks become active once temperatures hit 4 C, and they’ll start looking for a blood meal from animals — or humans.

“The black-legged tick and the western black-legged tick out in the West carry Lyme disease and other diseases. So when we’re bitten by ticks, we’re at risk of acquiring these diseases,” said Dr. Sarah Keating with the Canadian Lyme Disease Foundation.

This is because ticks are really good at spreading disease, she said. They have their own microbiome, just like we do, full of various microorganisms.

When a tick starts feeding, some of these organisms can move into its salivary glands. Then, as the tick injects saliva into our skin to keep the blood flowing and avoid detection, those pathogens can enter our bloodstream and potentially cause disease.

Milder winters mean more ticks can survive winter under leaf litter, Keating said.