Lyme Disease in Dogs: What Burlington Pet Owners Should Know in 2026

A woman called our front desk last spring, half in a panic. She’d found a small dark speck tucked behind her retriever’s ear after a walk through the woods, and she couldn’t tell if it was a scab or something alive.

We hear that one a lot around here. Burlington backs onto a lot of trail and forest, and ticks come with that territory.

This guide covers what our team here on Brant Street tells those callers. How worried to be, what to do first, and how to keep your dog off next spring’s call list.

The Merck Veterinary Manual explains dogs get Lyme disease from the bite of an infected blacklegged (deer) tick, and that the tick usually needs to stay attached and feeding for roughly 24 to 48 hours before it can pass the bacterium along. Finding and removing ticks quickly is your strongest protection.

If this is happening right now If your dog is suddenly collapsed, vomiting repeatedly, refusing food and water, or acting extremely lethargic, call us right away at (905) 336-4002. If you think your dog swallowed a tick-prevention product or another poison, the Pet Poison Helpline is 855-764-7661. Outside our hours, use our after-hours care page.

How do dogs get Lyme disease?

The Merck Veterinary Manual explains that dogs catch Lyme disease when a blacklegged tick carrying Borrelia burgdorferi, the spirochete bacterium behind Lyme, attaches to the skin and feeds. The manual reports that transmission usually happens 36 to 48 hours into the tick’s blood meal.

Cornell notes these ticks are tiny, from the size of a poppy seed to a sesame seed. That small size is the whole problem.

A tick this small can settle into an ear fold, between toes, or under a collar and go unnoticed for a day or more.

The odds of a single bite mattering aren’t trivial in a place like ours, either. The Companion Animal Parasite Council reports that in high-risk areas, over half of questing (actively seeking) nymph and adult blacklegged ticks have been shown to carry B. burgdorferi.

That’s why we treat every attached tick as worth acting on, not shrugging off.

What are the signs of Lyme disease in dogs?

Most infected dogs never look sick at all. The American Veterinary Medical Association reports that only 5% to 10% of infected dogs go on to develop signs of illness, and Cornell adds that when signs do appear, they usually show up 2 to 5 months after the bite.

The signs Cornell lists include fever, shifting-leg lameness, swollen and painful joints, lethargy, decreased appetite, and swollen lymph nodes. “Shifting-leg lameness” is a useful clue.

It means the limp moves around, sore on one leg for a day or two, then apparently fine, then sore on a different leg.

Because the gap between bite and illness can be months, owners rarely connect the two. A dog that seems stiff or off his food in late summer may have picked up a tick back in spring.

If your dog shows any of these signs, it’s worth mentioning the tick history when you call.

How common are ticks in Burlington and Halton Region?

Very common, unfortunately. Halton Region Public Health classifies all of Halton, including Burlington, as an established blacklegged tick risk area, and in 2025 Halton tested 106 blacklegged ticks, with 41 (about 39%) carrying the Lyme bacterium plus 2 that carried the bacterium behind Anaplasmosis.

Some local greenspaces stood out. Halton’s 2025 surveillance found the highest counts of infected ticks at a handful of well-used spots.

Source: Halton Region Public Health, 2025 tick surveillance.

None of this means you should avoid the trails. It means checking your dog after a walk is a Burlington habit worth keeping.

For context on how these zones get drawn, Public Health Ontario defines an established risk area as a 20 km radius around any spot where blacklegged ticks are confirmed by drag-sampling. It updates its Vector-Borne Disease tool annually for tick data.

Can Lyme disease in dogs be serious?

It can be, though most dogs stay healthy. Cornell warns that a kidney form called Lyme nephritis (Lyme-related kidney inflammation) is the most serious presentation and is often fatal, and the AVMA reports kidney disease develops in roughly 1% to 5% of infected dogs.

That’s why lingering illness always deserves a proper look. The warning signs Cornell lists for Lyme nephritis are worth knowing: vomiting, not eating, increased thirst and urination, weight loss, and extreme lethargy.

These are the same signs that overlap with several other serious problems.

If your dog shows that cluster, especially the drinking-and-peeing-more pattern alongside weight loss, don’t wait it out. This is the kind of case our critical care team wants to see sooner rather than later.

How do I safely remove a tick from my dog?

Following Cornell’s guidance, grasp the tick close to the skin with fine-tipped tweezers or a tick-removal tool and pull straight out with slow, steady traction. Halton Region notes that a tick attached for less than 24 hours carries an extremely low risk of transmitting Lyme.

That last point is the reason daily checks matter so much. Speed is on your side.

After you remove it, clean the spot and drop the tick in a small sealed bag or container. Some owners like to hold onto it in case identification helps later.

Then call us. We can talk through whether your dog needs testing or monitoring based on where you were and how long it was attached.

How can I prevent Lyme disease in my dog?

The Companion Animal Parasite Council recommends daily tick checks, avoiding tick habitat, year-round tick-preventive products (acaricides) that carry a label claim against these Ixodes ticks, and vaccinating dogs that live in or travel to endemic (high-risk) areas like ours. Ask us which combination fits your dog.

Protect yourself on the same walks. Halton Region recommends repellents containing DEET or Icaridin, checking your body after you’re outdoors, and tumbling your clothing in a dryer on high heat for at least 10 minutes to kill any ticks.

Timing matters too. The CVMA reports ticks can be active any day temperatures reach about 4°C, so seasonal-only prevention leaves gaps.

If you’re due for a checkup or want to review your dog’s coverage, our wellness and vaccinations team can walk you through the options.

When are ticks active in Ontario?

Year-round now, in practical terms. The CVMA reports ticks can be active any day the temperature climbs to about 4°C, which is why Canadian veterinary groups have moved from a spring-to-fall mindset to year-round prevention, and a mild January thaw is enough to wake them up.

Lyme is also climbing across the country. The Public Health Agency of Canada reported a preliminary 5,809 human cases in 2024, over 20% annual growth, with the incidence rate rising to 14.1 per 100,000 from 11.9 the year before.

Ontario carries a large share. The Public Health Agency of Canada reports Ontario had the most cases of any province in 2024 at 2,369 (a 27% year-over-year jump), and that 96% of all Canadian cases came from Ontario, Nova Scotia, and Quebec.

The Public Health Agency of Canada also reports that about 67% of locally-acquired human cases with known onset dates fell in June through August, the same window your dog is most exposed.

This article is educational and isn’t veterinary advice or a substitute for an exam. If you’re worried about your pet right now, call us at (905) 336-4002 or your nearest emergency veterinary hospital.

Not sure whether your dog needs to be seen after a tick bite? We’re glad to take a look and map out prevention that actually fits your household.

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Frequently asked questions

How long does a tick need to be attached to infect my dog?

The Merck Veterinary Manual reports a blacklegged tick generally needs to feed for about 24 to 48 hours before it can transmit the Lyme bacterium, and that transmission usually occurs 36 to 48 hours in. Halton Region adds that a tick attached under 24 hours carries an extremely low risk, which is why fast removal helps so much.

What does a blacklegged tick look like?

According to Cornell, blacklegged (deer) ticks are very small, ranging from the size of a poppy seed to a sesame seed. That tiny size is exactly why they’re so easy to miss on a dog, especially in ear folds, between the toes, or under a collar, so a hands-on check after walks beats a quick glance.

Is there a Lyme vaccine for dogs?

The Companion Animal Parasite Council recommends vaccination as part of prevention for dogs living in or travelling to endemic areas, alongside daily tick checks and year-round tick-preventive products. Because Burlington sits in an established risk area, a vaccine may make sense for your dog. Ask our team whether it fits your dog’s lifestyle and travel.

Where in Burlington are ticks most common?

Halton Region Public Health’s 2025 surveillance found the highest counts of Lyme-positive blacklegged ticks at Sedgewick Forest, Aspen Forest Trail, and Langtry Park. That said, all of Halton is classified as an established tick risk area, so ticks aren’t limited to those spots. Check your dog after any walk through grass, brush, or wooded trail.

Do I need tick prevention for my dog in winter?

Often, yes. The CVMA reports ticks can be active any day temperatures reach about 4°C, so Canadian veterinary groups now recommend year-round prevention rather than stopping in fall. A mild winter thaw can bring ticks out, and gaps in coverage are when dogs get caught. We can help you choose a product schedule that fits our climate.

My dog had a tick but seems fine. Should I worry?

Usually the odds are in your favour. The AVMA reports only 5% to 10% of infected dogs ever develop signs, and Cornell notes that when signs do appear, it’s often 2 to 5 months after the bite. So “fine today” doesn’t fully rule it out. Watch for fever, limping, or low appetite, and call us if anything changes.

Sources

Local and provincial public health data

1. Halton Region Public Health. “Lyme Disease.” halton.ca.
2. Public Health Ontario. “Ontario Vector-Borne Disease Tool.” publichealthontario.ca.
3. Public Health Agency of Canada. “Lyme Disease Surveillance in Canada: Annual Report.” health-infobase.canada.ca.

Veterinary clinical sources

1. Merck Veterinary Manual. “Lyme Disease (Lyme Borreliosis) in Dogs.” merckvetmanual.com.
2. American Veterinary Medical Association. “Lyme Disease in Dogs.” avma.org.
3. Cornell University College of Veterinary Medicine, Riney Canine Health Center. “Lyme Disease.” vet.cornell.edu.
4. Companion Animal Parasite Council. “Lyme Disease Guidelines.” capcvet.org.
5. Canadian Veterinary Medical Association. “National Tick Awareness Month.” canadianveterinarians.net.