In the last few years, Health Canada has tracked a persistent rise in cases of Lyme disease聽鈥 and as the planet warms, those numbers are expected to continue climbing, experts say.
On the back of an unusually warm winter, ticks are already being spotted in Ontario聽鈥 at numbers more than double what was seen the same time last year.
Given climate change, the cold-sensitive ticks have expanded their habitats further north every year, researchers tell the Star. Advocates are questioning whether Canada is prepared to cope with the rise of Lyme disease.
Canadian luminaries from Avril Lavigne to Justin Bieber, as well as thousands of citizens every year, can attest to the severity of the illness, which can cause life-long health issues. We previously asked a panel of experts to break down the issue 鈥 here’s what you need to know.
Why are ticks dangerous?
As parasites that feed from the blood of a wide range of species, ticks can occasionally spread disease from one host to another, said Jade Savage, an entomologist and a professor at Bishop鈥檚 University.
Lyme disease is the most common tick-borne illness in Canada, and it鈥檚 mainly transmitted through the blacklegged tick, Savage continued. These ticks can also spread .
The first blacklegged ticks were spotted in Canada roughly ; since then, the bugs have been 鈥渟lowly expanding its range,鈥 Savage said.
To track their spread, Savage created in 2014聽鈥 a 鈥渃itizen science project鈥 where people across Canada can submit images of ticks and where they were found. Locations are mapped so users know which areas are more prone to ticks.
Since the start of 2024, just under a hundred blacklegged ticks were reported in Ontario 鈥 more than double what was logged at the same time the previous year.聽More than 2,500 blacklegged ticks were recorded in the province in 2023, compared to a bit over 2,100 in 2022.聽
That said, Savage noted the growing public awareness of her site likely contributed to the recent spike in numbers, and that it only started taking reports in Ontario in 2019.
What is Lyme disease?
Lyme disease is mainly caused by a spiral-shaped bacterium called Borrelia burgdorferi, said George Chaconas, a professor specializing in Lyme disease at the University of Calgary Cumming School of Medicine.
Symptoms of Lyme disease generally appear in , the first often manifesting days after a bite, and the second sometimes taking months to materialize.
In the early stage, about half of people bitten develop a rash shaped like a bullseye at the site of the bite, Chaconas said. If you find an expanding, target-shaped rash on your body, speak to your doctor immediately, he said. However, rashes of other shapes or even no rash at all is also possible.
Once the bacterium is in the blood, it can sail to different parts of your body, causing different symptoms depending on where it lands, Chaconas said.
, these can show up days or even months after a tick bite, and may include: severe headaches, arthritis with severe joint pain and swelling, pain in tendons, muscles, joints and bones, heart palpitations or irregular heartbeat, facial palsy, and more.
The early stages of Lyme disease can be effectively treated with a two to three week course of antibiotics like聽doxycycline and聽amoxicillin, but is much harder to treat later on, according to .
鈥淭reated Lyme disease typically goes away and the story is over,鈥 said Chaconas. 鈥淏ut not always.鈥
Similar to long COVID, some people with Lyme disease develop posttreatment Lyme disease syndrome, or PTLDS, and end up with symptoms that persist for 鈥渨eeks, months and years,鈥 Chaconas said.
A found over 27 per cent of people tested with Lyme disease developed long-term symptoms.
Why are we seeing more cases?
From 2009 to 2022, the latest data available, Health Canada has received聽17,080 reports of Lyme disease across the nation.
Annual cases have increased more than ten-fold since 2009, when just 144 cases were reported; in 2021,聽3,147 infections were logged. Preliminary data for 2022 lists聽2,168 infections, though this number may rise with time as more data comes in.
Health Canada notes the actual number may be larger due to under-reporting or misdiagnosis. Unfortunately,聽聽may frequently return false negatives.聽
, the current testing approach detects just 29 to 40 per cent of early cases right after the onset of the tell-tale rash. This improves to a 29 to 70 per cent sensitivity two to four weeks after symptoms appear.
Katie Clow, an assistant professor at the Ontario Veterinary College specializing in tick-borne illness, said 鈥渕ost of the evidence supports that it’s climate change that is driving鈥 the rise in Lyme disease.
Canada is typically too cold for most ticks to reproduce, but with warmer summers and shorter winters, ticks have gained a foothold in areas they鈥檝e previously never been seen, she said.
Nova Scotia has the highest ratio of ticks to people in Canada, the experts say, and is second only to Ontario in the total number of reported ticks.
When and where are ticks most active?
According to Savage, blacklegged ticks are most active anytime from spring to fall; adults are more common in the spring and fall, and nymphs 鈥 an early life stage of the tick 鈥 are more common in late spring to early summer.
These time periods aren鈥檛 set in stone 鈥 the blacklegged tick can survive year-round 鈥渁s long as temperatures are above zero,鈥 Savage said. But if it鈥檚 too hot, like in the height of summer, they can also dry out easily.
Given the聽abnormally warm weather this winter, ticks may emerge earlier than is usual in 2024.
There are actually two species of blacklegged tick in Canada: the western blacklegged tick mainly resides in British Columbia, while the eastern blacklegged tick occupies Manitoba to the east coast, Savage said.
Health Canada has highlighted at-risk areas on their . These areas mostly stick close to the border, and include major cities like Toronto, Ottawa, Winnipeg, Victoria and Halifax.
Alberta, Saskatchewan and the territories have fewer ticks due to their climates; no cases of Lyme disease have ever been reported to Health Canada from the territories.
Enter your postal code on to check if your neighbourhood is at risk.
How can we protect ourselves?
The most important thing to do is familiarize yourself with what a tick looks like and perform routine tick checks after hiking or other activities, said Janet Sperling, president of the Canadian Lyme Disease Foundation.
She recommends checking for ticks while in the shower, when you鈥檙e already undressed.
鈥淚f you’re in the shower and you feel a little lump in your hair, go get somebody to actually look for you,鈥 she said. 鈥淒on’t assume that you can ignore it.鈥
If you do spot an attached tick, grab some clean, fine tipped tweezers and pinch the bug close to the skin as possible. Using slow, even pressure, pull the tick directly up out of your skin, trying to keep the mouth parts intact. Then thoroughly clean the area with soap and water or rubbing alcohol, according to Health Canada.
As it can take up to 24 hours for an attached tick to transmit Lyme disease, Sperling says it鈥檚 crucial to remove ticks as soon as possible.
Don鈥檛 crush a tick with your fingers. Sperling strongly recommends saving the tick in the freezer, in a bag labelled with the date and location of the bite. That way if you develop symptoms later, you can take the tick directly to the doctor to have it tested.
When walking in nature, Sperling recommends tucking your pants into your socks or at least wearing long clothing if possible. Light-coloured clothing is best, because then you could better spot ticks if they鈥檙e on you.
As ticks prefer the cool of tall grasses and foliage, try to keep your lawn short in summer and take extra care when walking through brushes and thick foliage, she said.
Sperling also recommends chemical insect repellents containing DEET or permethrin.
鈥淲e鈥檙e going to have to live with these ticks 鈥 they鈥檙e here to stay,鈥 said Sperling. 鈥淏ut don’t let the fear of ticks prevent you from going outside. It just means that you need to know what you’re getting yourself in for.鈥
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