Seasonal advisory
Blacklegged ticks active across southern Canada
Blacklegged tick nymphs — the life stage responsible for most Canadian Lyme cases — are at peak activity from late April through June in southern Ontario, southern Quebec, southern Manitoba, and the Maritimes. PHAC’s risk maps continue to expand year over year; areas that weren’t classified as Lyme risk zones five years ago often are now.
If you spend time in long grass, leaf litter, or forest edges anywhere in those regions this spring, assume blacklegged ticks are present. Daily tick checks during May and June catch the overwhelming majority of bites before the 24-hour transmission window closes.