Invasion of the ticks: Watch their remarkably fast spread across Canada

Ticks are pushing farther across Canada every year, and the diseases they carry are coming with them. Reported Lyme disease cases climbed from 522 in 2014 to 5,239 in 2024, according to the Public Health Agency of Canada.

National Post reached out to three experts for more information on where ticks are spreading, why and how to stay safe. Manisha Kulkarni is a professor at the University of Ottawa’s School of Epidemiology and Public Health. Virginie Millien is a biologist at McGill University. Luis Anholeto is a lab manager at the Canadian Tick Research and Innovation Centre at Acadia University.

Millien spoke by phone. Kulkarni and Anholeto responded by email. Their answers have been edited and condensed for clarity and length.

How big is Canada’s tick problem now compared to a decade ago?

Kulkarni: We’ve seen a dramatic increase in tick populations across Canada in the last decade, especially the blacklegged ticks (deer ticks) that can carry Lyme disease. Ten years ago, there were established tick populations in defined pockets of southern Manitoba, southern and eastern Ontario, southern Quebec, New Brunswick and Nova Scotia, but since then we’ve seen an expansion of these populations further north in all provinces, including around major population centres like Toronto, Ottawa and Montreal.

Which parts of the country have been hit hardest, and is that map still changing?

Millien: Ontario is actually a hotspot. It’s number one in terms of abundance of ticks and number of Lyme disease cases. Quebec is not far behind, but Ontario, this is where it started, Long Point.

Anholeto: Nova Scotia has consistently had the highest incidence rates in the country.

What’s driving the spread, and how much of it comes down to climate?

Kulkarni: Climate change and the associated warming temperatures are a major force behind the spread of blacklegged ticks in Canada. They can survive further north, where it was once too cold, and there’s a longer warm season for them to complete their life cycle. But other factors, like land-use changes, are also at play. Urban expansion into woodlands and resulting forest fragmentation creates an ideal habitat for white-tailed deer and white-footed mice, and in turn, ticks.

Millien: Up until recently, none of them would survive the winter. But now that we have ticks that survive, they reproduce locally, so the pathogen is circulating and it’s established.

Which tick-borne illnesses should people actually worry about, and how serious are they?

Kulkarni: The most common tick-borne illness in Canada is Lyme disease, which can be very serious if it’s not treated promptly. Other serious tick-borne illnesses are also on the rise, such as Anaplasmosis, Babesiosis and Powassan virus.

Anholeto: Beyond Lyme, anaplasmosis is increasing in Canada. Powassan virus is rare but can cause encephalitis. We also have Rocky Mountain spotted fever, a rare but potentially deadly infection that is spreading northward in Canada due to climate change.

How do people avoid getting bitten?

Kulkarni: People can avoid tick bites by staying on the trails in wooded areas where ticks live, and by wearing long clothing, using insect repellent that contains DEET or icaridin, or wearing permethrin-treated clothing.

Anholeto: Wear light-coloured clothing, it makes ticks easier to spot, and tuck your pants into your socks. After being outdoors, do a full-body tick check, paying special attention to under the arms, behind the knees, the waist, the groin and the scalp. Also, check children and pets.

If someone finds a tick on them, what should they do?

Anholeto: Stay calm, finding a tick early is actually good news. Ticks need to remain attached for hours before transmitting the bacteria. Use clean, fine-point tweezers to grasp the tick as close to the skin as possible and pull upward with slow, steady pressure. Do not twist or squeeze the tick.

Kulkarni: In Ontario and some other provinces, if you have been bitten by a tick, you can visit a pharmacy to see if you’re eligible for post-exposure prophylaxis. Monitor for symptoms and see a healthcare provider asap if you have a rash, fever, headache, or other flu-like symptoms.

What’s the biggest misconception about ticks or Lyme disease you’d want to clear up?

Anholeto: I have been seeing posts on social media lately about the lone star tick in Canada. This tick is associated with alpha-gal syndrome, the so-called red meat allergy from a tick bite. It’s a real condition, but the risk of locally acquired alpha-gal syndrome in Canada is low because the primary tick responsible, the lone star tick, is not established here. Right now, if you get bitten by a tick in Canada, the realistic threats are Lyme disease, anaplasmosis, babesiosis and Powassan virus. Be wary of misinformation.

Anything else Canadians should know heading into summer?

Millien: They’re not that scary. The problem is that we become too comfortable. We need to be reminded, stay on the trail or wear long pants and then the tick check. It’s just a tweezer and 90 degree pull out straight, because you don’t want to leave the head in there.

• What to know about the rise of tick-borne anaplasmosis in Canada
• Tick-linked meat allergy may be far more common than previously known

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