Trekking through high grass at the cottage could come with a cost this summer. Tick bites are on the rise, and the microscopic menace is moving north, says the Public Health Agency of Canada (PHAC).
Black-legged ticks and deer ticks are the ones to watch out for. They’re the main culprits in spreading lyme disease, a bacterial infection that if left untreated can cause symptoms such as facial palsy, swollen joints, and inflammation of the brain and spinal cord.
According to PHAC’s most recent data, lyme disease cases have risen exponentially over the 16 years it’s been tracking them, from 144 in 2009 to 5,239 in 2024. The situation’s even more dire south of the border where the Centers for Disease Control and Prevention (CDC) reported 89,000 lyme disease cases in the U.S. in 2023.
One of the reasons for the continued uptick in lyme diseases cases is climate change. Warmer temperatures mean tick season starts earlier and ends later. It also allows ticks to mature faster. They hop rides on mating animals, such as deer, mice, and even birds, transporting them to new territories. With northern areas such as cottage country staying warmer for longer, ticks can establish themselves in the environment.
The National Collaborating Centre for Environmental Health estimates that ticks will increase their northward spread by 35 to 55 kilometres per year. And a Canada Communicable Disease report predicted that by 2050, 95 per cent of the Quebec population will live in a climate zone conducive to ticks.
However, for now, the majority of tick populations cluster around the southern sections of Canada’s provinces. On its monitoring page, PHAC has released a list of more than 1,100 municipalities and the postal code areas within those municipalities most at risk of lyme disease.
According to PHAC’s mapping, high-risk areas in Ontario are concentrated around the Greater Toronto Area, the shores of the Great Lakes, and in the Saint Lawrence Valley extending from Kingston northeast towards Ottawa.
In Quebec, high-risk areas are around Montreal and Laval, as well as parts of the Outaouais, Lanaudiére, and Laurentides regions.
In Manitoba, high-risk areas are anywhere below the 53rd parallel, including Winnipeg and the Ontario border. In B.C., most of Vancouver Island in considered high-risk, as well as the province’s coastal Lower Mainland and several river valleys in the south.
In the Maritimes, all of Nova Scotia is considered high-risk, as well as a large swath of New Brunswick.
To avoid tick bites, PHAC recommends wearing closed-toe shoes and applying insect repellent containing DEET. It also suggests wearing light-coloured long-sleeved shirts and pants to spot ticks quickly, and to tuck shirts into pants and pants into socks so that ticks can’t crawl under clothing.
If bit by a tick, remove it as soon as possible. Lyme disease is usually transmitted after the tick’s been attached for 24 hours. They tend to migrate to hard-to-see places, such as the armpit, groin, or scalp. It’s best to use tweezers to lift the tick straight up. Crushing the tick could force its body fluids into the skin increasing the chance of infection. Once the tick’s been removed, wash the area and monitor for flu-like symptoms.
For those who do contract lyme disease, it can be treated with antibiotics. Although, even with antibiotics, symptoms such as pain, fatigue, and difficulty thinking can last as long as six months.
To avoid treatment after infection, pharmaceutical companies Pfizer and Valneva are working on a vaccine known as VLA15 that would prevent people from contracting lyme disease. The vaccine is currently in phase three of clinical trials with 9,437 participants enrolled. The companies plan to monitor the participants for signs of lyme disease until the end of lyme disease season in 2025.
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