To get Lyme disease, a person must be bitten by a blacklegged tick that is infected with the Borrelia burgdoferi bacteria. The risk of human infection increases with the time a tick is attached to a person and usually requires the tick to be attached for 24 hours or more.
The risk of acquiring Lyme disease in Toronto is believed to be low.
Ticks are found in wooded or bushy areas with lots of leaves on the ground or where there are tall grasses. Lawns, mowed grass, sports fields or paved areas are not where blacklegged ticks are usually found. Ticks cannot fly or jump. Instead they wait for a host (person, animal or bird), resting on the tips of grasses and shrubs. If a person brushes the spot where a tick is waiting, it quickly climbs aboard. It then finds a suitable place to bite. Ticks can attach to any part of the human body but, if found, may be in hard-to-see areas such as the armpits, groin and scalp.
Blacklegged ticks pass through three different active life stages (larva, nymph, adult). Ticks are small, ranging in size from a poppy seed to a pea. The size of the tick varies depending on its life stage and whether it has fed recently.
The nymphal stage typically occurs during the summer months and is the stage most responsible for human infections. This is due to their very small size (less than 2 mm) which prevents people from noticing them on their body. Adult ticks can also transmit Lyme disease bacteria, but they are larger (5 mm) and therefore more likely to be discovered and removed before they have had time to transmit the bacteria.
Early detection and removal of ticks is important in the prevention of Lyme disease.
How to avoid tick bites
- Stay in the centre of trails, to prevent ticks from getting on you
- Check your full body and head for ticks and shower after spending time outdoors in wooded or bushy areas with lots of leaves or tall grass
- Wear light coloured clothing so you can easily spot ticks. Long sleeves and long paints are recommended.
- Apply insect repellant containing DEET and follow the manufacturer's instructions
- If you find a tick on your body, remove it as soon as possible.
- Remember to also check your children and pets for ticks
On your property
- Mow the lawn frequently; remove leaf litter, brush and weeds from the edge of the lawn
- Restrict the use of groundcover in areas frequented by people or pets
- Keep tree branches and shrubs trimmed to let in more sunlight
- Stack firewood piles neatly
- Restrict tick migration into recreational areas by placing a three-foot wide barrier of wood chips or gravel between lawns and wooded areas and around patios and play equipment
- Ticks feed on rodents, deer and birds. Discourage rodents by sealing stonewalls and small openings around the yard. Use plantings that do not attract deer or exclude deer by fencing. Keep bird feeders away from the house.