Across Canada, a concerning trend is emerging: tick-borne illnesses, including Lyme disease, are on the rise. Public health officials are pointing to climate change as a significant driving force behind this increase, altering tick habitats and expanding their geographical range. This has profound implications for public health and outdoor recreation.
“Climate change in Canada is happening at a much more accelerated rate than we see in parts of the rest of the world,” explains Heather Coatsworth, chief of field studies at the National Microbiology Laboratory in Winnipeg. “Ticks, require a certain amount of heat and humidity to complete their life cycle.” Warmer temperatures and altered precipitation patterns create ideal breeding grounds and extend the active season for these creatures.
Before, Ontario, Quebec, and Nova Scotia were considered the primary hot spots for blacklegged ticks. Now, with the changing climate acting as a catalyst for change, the tick population is growing in Manitoba, Saskatchewan, Alberta, and British Columbia, according to Coatsworth.
The rising numbers have spurred calls for increased awareness and education, not only among the public but also within the medical community.
Janet Sperling, president of the Canadian Lyme Disease Foundation, notes: “A lot of doctors have been told , this was their training , ‘you can’t get Lyme disease in Alberta; if you don’t have a travel history don’t worry about it.’ There’s no doubt that it has changed and the education hasn’t caught up with some of the doctors.”
The shift in the prevalence of ticks has presented challenges for Canadians. Here are factors impacting the shift:
- Climate Change: Warmer temperatures and increased humidity create favorable conditions for tick survival and reproduction.
- Expanded Tick Habitats: Ticks are now found in regions where they were previously uncommon.
- Increased Awareness Needed: Public and medical professionals need updated information on tick-borne diseases.
- Diagnostic Challenges: Symptoms of tick-borne diseases can mimic other illnesses, leading to delayed or missed diagnoses.
The numbers tell a stark story. When provincial public health units started monitoring Lyme disease in 2009, they reported just 144 cases across the country. The preliminary case count for 2024 is a staggering 5,239, according to the Public Health Agency of Canada. Experts warn that the actual number is likely higher, as many infections may go undiagnosed due to general symptoms.
Coatsworth paints a concerning picture of the future: “There’s estimates that if things keep going the way they are and climate change keeps going the way things go, that in 25 years we’d have about half a million cases of Lyme disease here in Canada.”
Lyme disease presents with symptoms such as fever, chills, fatigue, headache, swollen lymph nodes, and muscle and joint aches. A telltale sign is a bull’s-eye rash, but Coatsworth cautions that roughly 30% of infected individuals never develop one.
Beyond Lyme disease, other tick-borne illnesses are also on the rise. Some provinces have started monitoring anaplasmosis, babesiosis, and Powassan virus. Anaplasmosis, in particular, is showing rapid growth. Cases have surged from 10-50 per year around 2012 to over 700 reported last year. Symptoms of anaplasmosis are similar to Lyme disease, but without the rash, and can include cough, diarrhea, abdominal pain, and vomiting. Babesiosis can cause similar symptoms to Lyme disease as well without a rash, but often leads to anemia. Powassan virus can cause fever, chills, headache, vomiting, and neurological symptoms like encephalitis and meningitis.
Lyme disease and anaplasmosis, being bacterial infections, are treatable with antibiotics like doxycycline. Babesiosis, caused by a parasite, is treated with anti-parasitic medications. Unfortunately, there is no specific treatment for Powassan virus; patients receive supportive care to manage symptoms.
The diseases are carried by two types of blacklegged ticks: Ixodes scapularis (deer tick), found primarily in Ontario, Quebec, and Nova Scotia, and Ixodes pacificus (western blacklegged tick) in British Columbia. These ticks feed on the blood of various animals, including deer, mice, rabbits, birds, and reptiles. Birds can carry ticks over long distances, contributing to their spread. The ticks get infected if the host animal is infected, and they in turn transmit the disease to humans when they bite them and latch on.
Dr. Curtis Russell, a vector-borne disease specialist at Public Health Ontario, emphasizes the small size of these ticks: “A lot of people are very surprised when I show them a blacklegged tick. They can’t believe how small they are.” Adult ticks are about the size of a sesame seed, while younger ticks are even smaller, resembling poppyseeds.
Ticks inhabit wooded and grassy areas, including forests, parks, hiking trails, and even peri-urban spaces like local neighbourhood parks with squirrels and deer.
For many, spending time outdoors is essential for mental and physical wellbeing. “It challenged previous assumptions,” noted avid hiker Sarah Miller, who always believed she was safe from ticks in her urban park, before discovering one on her leg after a walk.
So, how can Canadians protect themselves? Here’s a summary of expert advice:
- Wear long sleeves and pants when possible.
- Use insect repellent containing DEET or other effective ingredients.
- Choose light-colored clothing to easily spot ticks.
- Stay in the middle of trails to avoid contact with foliage.
- Perform full-body tick checks after outdoor activities, paying attention to the hairline, armpits, groin area, and back of the legs.
- Take a bath or shower after spending time outdoors.
- Wash and dry clothes on high heat to kill any ticks.
If you find a tick attached to your skin, remove it promptly with tweezers. Grasp the tick as close to the skin as possible and pull it straight up without twisting. After removal, clean the bite area with soap and water.
Etick.ca, a service run by universities and public health agencies, allows you to submit a photo of the tick and information about where you were bitten to determine the type of tick and the risk of tick-borne diseases in the area. If you develop symptoms after a tick bite, consult a healthcare provider and inform them of your possible exposure.
The lasting impact of climate change on tick-borne illnesses is undeniable. Increased vigilance, education, and preventive measures are crucial to protect public health in a changing environment. Social media platforms are buzzing with discussions about tick prevention. One user posted on X.com, “Just pulled my first tick of the season off my dog! Remember to check your pets and yourselves after being outside.” Another wrote on Facebook: “Anyone else experiencing more ticks this year? It’s crazy!” Comments like these highlight the growing concern among Canadians about the rising tick population. A Instagram user wrote; “went for a walk last week and have a rash I am not sure about. So scary!”
This report was first published June 28, 2025.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.