The Ticks are Advancing: Lyme Disease in Ontario & Quebec

The Northward Migration of Lyme

Lyme disease, once considered a rare concern in Canada, has become a major health threat across Southern Ontario, Quebec, and the Maritimes. The black-legged tick (deer tick), which carries the Borrelia burgdorferi bacteria, is expanding its Canadian range northward by dozens of kilometers every single year. This migration is fueled by warming climates and the movement of migratory birds and deer.

Why the "Winter Break" is a Dangerous Myth

Many Canadian pet owners stop tick preventatives in October, assuming the first frost kills the threat. This is a dangerous misconception. Black-legged ticks are not killed by frost; they simply go dormant and become active again any time the temperature is above 4°C. In regions like Southern BC or the Great Lakes area, "thaw" periods in mid-January are enough for ticks to emerge and seek a blood meal.

Full Body Inspections: The "Tick Check" Routine

After every walk in tall grass, leaf litter, or wooded areas, perform a meticulous "tick check." Ticks love warm, dark, and hidden places. Check between the toes, inside the ears, under the armpits, and around the base of the tail. Feel for small bumps that were not there before; an unfed black-legged tick can be as small as a poppy seed and very difficult to spot visually.

Backyard Environmental Control

To reduce the risk in your own backyard, keep your lawn mowed short and clear away any piles of leaves or brush where ticks thrive. Consider creating a "buffer zone" of woodchips or gravel (at least 3 feet wide) between your lawn and any wooded areas. This creates a dry barrier that ticks—who are prone to dehydration—are reluctant to cross.

Symptoms to Watch For

In dogs, Lyme disease doesn't usually cause the "bullseye" rash seen in humans. Instead, watch for sudden lameness (which can "shift" from one leg to another), fever, lethargy, and loss of appetite. If left untreated, the bacteria can lead to serious kidney damage or chronic joint issues.