The truth about ticks in Canada

The truth about ticks in Canada

Ticks are quickly spreading across Canada. Here’s everything you need to know about these creepy crawlies, including how to protect your dog from being bit.

Ticks are creepy crawly members of the spider family. They latch onto your dog (and you) and feed for days. You often find them as mole-like swollen bags of blood with legs attached, and their heads buried in the skin. And
that’s the good news.

The bad news (and the real problem with ticks) is that when they bite, attach and feed, they are sucking blood and passing along myriad potential diseases.

Worse yet, black-legged ticks, a stealthy and aggressive species, have quietly and rapidly invaded Canada. The same is true of other tick species (e.g. the lone star tick) that are expanding their territories northward from the US. All of which means you’ll want to polish up your knowledge of ticks and how to prevent tick bites – whether you live in Canada or travel south of the border.

Tick basics

Ticks have wandered the world for many years. Paleobiologists recently found ticks millions of years old preserved in amber – one with a Lyme disease-like bacteria in its gut. While Lyme is the most common disease black-legged ticks transmit, at least 16 different diseases are caused by pathogens (disease-causing microorganisms) transmitted by these ticks and others commonly in North America. To make matters worse, researchers regularly discover new tick-transmitted pathogens that cause diseases in multiple species, along with pathogens from other parts of the world that are globalizing.

Ticks transmit pathogens while feeding. They find their meals, politely called their “hosts”, by crawling up a branch or blade of grass. When a suitable host brushes by, the tick grabs on. After finding a warm, dark, moist spot, the tick then inserts its mouthparts, which consist of barbed harpoon-like hooks with a straw-like “tongue”. When it pierces the skin, the tick injects anticoagulants, immune suppressants, and an anesthetic so the host doesn’t feel the bite.

Blood is mostly water, so the tick pumps the watery part of blood back into the host – in the process sloshing microorganisms (potential pathogens) from its body back into the host’s bloodstream. Depending on the microorganism, this transmission can happen within minutes to days. The exact time required depends on the pathogen, the host, the tick and other factors.

The black-legged tick (Ixodes scapularis, I. pacificus)

There are many species of ticks, and from the point of view of people and their dogs, there really is no such thing as a good tick. The black-legged tick is a fairly new (and incredibly successful, from the tick’s standpoint) introduction to Canada. These ticks quite happily feed on anything with blood. They’ve been found on people, pets, wildlife, amphibians, reptiles, and birds.

It’s the black-legged tick’s taste for birds that allows it to spread. Young ticks can start feeding from a migratory bird in the spring, and as a result, the tick migrates north with the bird. In Canada, this mostly brings in ticks from the US, but sometimes they come from as far away as Europe or Asia.

While the bird does all the hard work of flying, the tick quietly feeds from its blood. When the bird arrives, the fully-fed tick drops off and can then moult into an adult. If that adult can find a meal and a mate, you get even more ticks – a female can lay a whopping 2,000 to 5,000 eggs.

Before climate change, many of these introduced ticks would die off in the winter. But now, between the changing climate and changing human activities, black-legged ticks are enjoying a population boom. Unfortunately, people and pets are not enjoying this population boom nearly as much, which is why you need to know how to protect your dog and yourself.

Preventing tick-borne diseases in dogs

Lyme disease is a concern in Canada, but it’s not the only tick-borne illness affecting dogs. Others include anaplasmosis, ehrlichiosis, and tick paralysis. For people who travel south with their dogs, the list of tick-borne diseases grows longer.

Preventing Lyme and other tick-borne diseases is achieved by preventing ticks from taking a blood meal (especially an extended one) from your dog. This can be accomplished with two basic prevention tactics:

1. Tick checks

These can be challenging to perform regularly (i.e. daily) and consistently, but do check tick attachment “hot spots” on your dog. The most common areas where ticks are found include the head (almost 50%), followed by the legs, neck and chest (all close to 10%).

2. Application of veterinary-approved tick prevention products applied as directed

It can be challenging to understand Bravecto, K9 Advantix II, NexGard and Simparica. It’s important to check with your veterinarian about specific products before obtaining them (or applying them) because your veterinarian
understands your dog’s unique breed and health concerns, knows where you live (i.e. what the tick risks are in your
region), and can modify recommendations for tick prevention based on your travel plans.

A third option to potentially help with Lyme disease prevention in your dog is vaccination. This can be a controversial topic because some vets question the efficacy of the vaccine as well as its duration of immunity, and it’s not for every dog. Be aware that vaccination for Lyme does not protect your dog against any of the other tick-borne pathogens.

Are ticks a risk to humans?

Black-legged ticks and other species are happy to feed from anything that has blood. So yes – this means they are a risk to you as well as your dog. Performing tick checks on yourself and your pup is one of the best ways to avoid disease. “Tick proofing” the back yard and learning about the signs and symptoms of Lyme disease in humans as
well as dogs is important. Ticks are small before they start feeding – about the size of a poppy seed for young ticks
and a sesame seed for the adults. So it is important to check carefully for tiny black specks that look like new freckles – freckles with legs.

Ticks are ancient but creepy creatures. They are now present in most of Canada and expanding in range and number every year. We need to pay attention to them because of the diseases they carry. Many good products and regular tick checks can help protect our dogs, while we humans have our big brains to help protect us. So get out and enjoy the great Canadian outdoors with your family members, four-legged and otherwise – but do so safely.

For more about ticks and ongoing research:
• Where to look for ticks on dogs and cats:
• Information on anti-tick products for dogs and cats:
• Information on canine Lyme: ACVIM consensus update on Lyme borreliosis in dogs and cats:
• Tick identification website – there are a number of tools and apps for this. One for Ontario is and one for Quebec is
• Preventing ticks in your yard:
• Information on Lyme disease in humans:

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Dr. Vett Lloyd is a professor of Biology at Mount Allison University, working on ticks and the pathogens they transmit. She is a founding member of the Mount Allison Lyme Disease Network and the Canadian Lyme Consortium, an interdisciplinary network of researchers tackling the biological, social and human dimensions of Lyme disease, and incorporating the Lyme patient community as full partners in this endeavour. She has a special interest in encouraging citizen science for tick surveillance activities as a way to help "tick proof" communities.