Lyme Disease Is On The Rise—And Climate Change Is To Blame

The disease already affects thousands of Canadian women. The climate crisis could mean an even greater number of infections.
An illustration of a doctor heading into a forest with a flashlight, looking for ticks(Illustration: Sunnu Rebecca Choi)

Maggie McColl first heard the joke about Lyme disease at a public talk about the illness in 2008. “The good news is, you’re not going to die,” she chuckles. “And the bad news is, you’re not going to die.”

McColl, based in Nanaimo, B.C., first experienced symptoms of what she now knows is Lyme disease a few years before attending the talk, in 2006. At the time, she was chair of Malaspina College’s geology department, teaching for about 15 years both in the classroom and through field trips into the bush. She had also conducted fieldwork in B.C. and the Yukon as an exploration geologist for 15 years before that. By spring 2007, her symptoms—which included headaches, a stiff neck, peripheral nerve pain in her arms, hands, legs and feet, skin lesions and rashes, deteriorating vision and worsening cognitive function—became so debilitating that she couldn’t work at all.

“I couldn’t tally the final grades,” says McColl, now 65, who had never experienced major health concerns before then. “I was in so much pain, I couldn’t move.” McColl sought medical help, cycling through more than 20 doctors and specialists in search of a diagnosis—including a naturopath, who, after trying “everything she could,” concluded that McColl likely had Lyme disease. But any relief McColl might have felt upon finally receiving an answer evaporated once she realized the arduous process of diagnosing and treating Lyme—an undertaking that requires unreliable blood tests and tireless advocacy on the part of patients when doctors dismiss their concerns.


Lyme disease is a bacterial infection primarily transmitted from animals to humans through tick bites, explains Dr. Vett Lloyd, a professor of biology at New Brunswick’s Mount Allison University as well as head of the university’s Lloyd Tick Lab. As a former Lyme patient—an experience that motivated her to research the disease—she understands it intimately.

Lyme-carrying ticks are concentrated in southern Canada, especially New Brunswick, Nova Scotia, southern Ontario, southern Quebec, southern Manitoba and some parts of B.C. But the climate crisis and changing landscape ecology have created new challenges: Tick populations are increasingly migrating northward, to areas they normally wouldn’t, likely due to warming temperatures. Because both people and ticks travel, the number of Lyme cases in Canada grew ninefold between 2012 and 2021. (The average age in reported cases is about 48 years old, though Lyme can occur in children as young as five.) The risk is so great that Dr. Theresa Tam, Canada’s chief public health officer, flagged Lyme disease as an illness to monitor in her 2022 report on the state of public health in the country, noting its propensity to spread amid a warming climate.

“There are more ticks, more infected ticks and more people getting in contact with them,” says Lloyd. “It’s a real problem—[and] it’s an increasing problem.”


The Public Health Agency of Canada reported 3,147 cases of Lyme disease across the country in 2021, but this number doesn’t accurately capture all the people with Lyme in Canada. Most patients—and their physicians—don’t consider Lyme when they get sick, because its symptoms, which vary between patients, can mirror other illnesses, depending on which area of their body the Lyme bacteria spreads to. Patients have reported experiencing flu-like symptoms, joint and muscle pain resembling arthritis, heart issues, depression and anxiety, extreme fatigue and declining cognitive function and motor function. (Shania Twain says the illness even affected her singing voice.) When doctors do consider Lyme, patients need to test positive on two subsequent blood tests for Lyme antibodies. Lloyd says there tends to be “a lot of dropout” on the road to a diagnosis, resulting in fewer Lyme cases being officially documented.

An adult female black legged tick—the tick species mainly responsible for spreading Lyme in Canada—is roughly the size of a sesame seed, while nymph or juvenile ticks are about the size of a poppy seed. Their size, as well the possibility of them attaching to areas of the body that are hard to see, like the scalp, armpit, back or behind the knees, make it easy for tick bites to go undetected. Complicating matters is the fact that Lyme’s only unique outward sign is a bull’s-eye red rash, which varies in appearance and may not even be present in some cases. If untreated, Lyme—as well as any co-infections the patient might develop—can cause muscle and joint pain, along with neurological and cardiac complications.


“Lyme disease is most treatable when the infection is localized to the skin around the tick bite,” says Dr. Melanie Wills, director of University of Guelph’s G. Magnotta Lyme Disease Research Lab. “Since Lyme is a bacterial infection, it can be treated with antibiotics. But between the numerous and confusing symptoms and a general lack of awareness about Lyme among Canadians and even some Canadian health care practitioners, the disease is often untreated or undertreated. That can lead to excruciating consequences.”

Marnie Freeman, a 55-year-old from Kamloops, B.C., was diagnosed with Lyme in January 2019 after battling various health issues for more than a decade. “I was having issues with cognitive function. I was having digestive issues. I was chronically fatigued,” she says. Anxiety and depression followed, as did numbness spreading from her face to her hands, legs and feet. Freeman’s doctors suspected multiple sclerosis (MS)—a common misdiagnosis—and eventually diagnosed her with autoimmune Hashimoto’s disease, where the immune system mistakenly attacks the thyroid gland. Yet her symptoms didn’t improve, prompting her to keep searching for answers.

“I really felt that we hadn’t found the underlying cause,” she says. “I’d been an active, fairly healthy individual for many years and I couldn’t understand why I was not myself anymore.”


Karen Kerwin, from Port Moody, B.C., had a similar experience. The 43-year-old first started experiencing symptoms in her late teens. She got a bull’s-eye rash at about age 17 and was diagnosed with ringworm, then developed what was diagnosed as mononucleosis caused by the Epstein-Barr virus. By her early 20s, she was experiencing chronic fatigue and a susceptibility to falling sick often. At 23, Kerwin developed Ménière’s disease, an inner ear disorder that can cause vertigo. About seven years later, she began experiencing neuropathy in her face, left arm and left leg that her doctor investigated for—but couldn’t clearly diagnose as—MS. Kerwin was eventually diagnosed with anxiety and depression.

“I was . . . basically told that it was in my head, that I was imagining this, that it wasn’t real,” Kerwin says.


She refused to believe that she was making up her symptoms, especially after they began affecting her cognitive abilities. Kerwin recalls having a hard time focusing or remembering words and was forgetting things, like where she parked her car, “all the time.”

Like McColl, both Freeman and Kerwin were recommended by a naturopath to investigate Lyme disease after health care professionals dismissed their concerns. Depending on how prevalent Lyme is in their region—and how prevalent aware- ness about it is—health care practitioners often overlook Lyme in patients, especially since its symptoms can resemble other diseases, such as MS, fibromyalgia and chronic fatigue.

“I was basically told that it was in my head, that it wasn’t real.”


In Canada, an official diagnosis requires a two-tiered blood test—in which blood is drawn once and tested twice—in a Canadian lab. In order to qualify for a second test, the first must come back positive for Lyme. But many Lyme patients across the country have trouble convincing their health care practitioners to test them for Lyme disease. When Kerwin brought up Lyme disease with her general practitioner, for example, they dismissed it.

When patients do get tested, their test often comes back negative. This is because in Canada, health care providers take a serological approach when testing for Lyme, gauging the immune system and the presence of antibodies to determine whether there is an infection. The immune system, however, frequently takes time to develop a strong response, creating a Catch-22: The symptoms needed for a Lyme diagnosis are often not present in the early stages of the infection, when it is easiest to treat with antibiotics. Treatment for prolonged cases, known as Post-Treatment Lyme Disease Syndrome, also involves an antibiotic regimen that varies in duration, depending on how long a patient has been living with Lyme, what symptoms they are experiencing and what treatment guidelines their doctors follow. In some cases, patients are able to recover with minor long-term effects.


After meeting with a neurologist and testing positive for Lyme, Kerwin was referred to infectious disease specialists, who, she says, “argue with [her] all the time” about whether she actually has the illness.

“I was treated in hospital on IV antibiotics for what was supposed to be six weeks’ time, but the infectious disease doctor at the hospital disagreed [with] that it was Lyme altogether, so [the] would only treat me for four weeks,” she says. After the four weeks, Kerwin says her health care practitioners assumed she was cured. When her symptoms continued, they concluded that she didn’t have Lyme—it was just in her head.

When patients test negative, as was the case with Freeman, they often get a second opinion by sending their blood for testing to other country’s labs, typically in the U.S. and Germany, which may test for wider strains or different antibody responses. Though those tests often come back positive, they aren’t always accepted by Canadian health care practitioners due to differing testing standards.


“Maggie McColl says she has spent more than $100,000 on private health care to treat her Lyme.”

“People point at anyone who thinks they have Lyme as being duped by for-profit labs from the States,” says McColl. “And I think, ‘The lab doesn’t get any more money if the test is positive or negative.’ If you’re refusing to test [me] in Canada, what else am I supposed to do?”


Without an official diagnosis in Canada, patients find it difficult to access care in the Canadian health care system, which many say gaslights them into thinking that they are making up their symptoms—or at least their severity. Many resort to privatized health care, frequently in the U.S., says Lloyd, creating “a profound inequality,” where patients who can afford to do so pay a hefty sum to regain their health.

Lyme disease also makes it difficult for patients to work, and they often cannot claim disability if they don’t have an official diagnosis. McColl, for instance, estimates that she has spent more than $100,000 out of pocket on private health care practitioners and additional testing while treating her Lyme dis- ease. Jody Wiebe, who is 36 and lives in Manitoba, estimates that her Lyme treatment has cost her “well over $10,000.”

The symptoms of Lyme can resemble those of Post-COVID-19 condition, or long COVID. Some Lyme patients hope that ongoing research into long COVID’s causes and treatments can help health care practitioners arrive at a consensus on the “controversial” debate about how to treat Post-Treatment Lyme Disease Syndrome—especially as climate change threatens an increase in cases.


With treatment, McColl, Wiebe and Kerwin have been able to manage most of their symptoms, though they are still no- where near their pre-Lyme selves. McColl’s cognitive function has improved and she has access to pain relief, but her immense fatigue only allows her to function for about four hours every day. Wiebe has trouble remembering things and finds her energy quickly drained. Kerwin says she never feels rested and still experiences neuropathy; she increasingly fnds herself cancelling plans as a result, cutting her off from her support system. The isolation Lyme disease patients experience from their peers combined with gaslighting from the medical system make their already debilitating experience even worse.

“It’s more work [treating] than it should have to be,” says Lloyd, adding that people—both inside the health care system and outside of it—have an important part to play in navigating Lyme by advocating for themselves and their communities. “But if you don’t have your health, you don’t have anything. So don’t lose hope [and] keep going.”


Originally published April 2023; updated March 2024.

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