What are tick-borne diseases?

Tick-borne diseases are transmitted to people and animals through the bite of an infected blacklegged tick (also known as a deer tick) and can potentially lead to severe illness. Tick-borne diseases include Lyme disease, Anaplasmosis, Babesiosis, and Powassan virus. Some types of tick-borne illnesses can be treated successfully with antibiotics. However, if left untreated, symptoms sometimes last from months to years and can cause serious health problems.

Blacklegged ticks live in woodlands, tall grasses and bushes, and are found throughout Ontario – including the five eastern counties. The number of infected blacklegged ticks is increasing each year.

Click here to check out the map of established risk areas for blacklegged ticks in Ontario – 2024.

Ticks are most active in the summer months, but can be found at any time of the year when the temperature is above freezing. Adult ticks are about the size of a sesame seed, while the immature nymphs can be as small as a poppy seed. When they’re full of blood, they can be as large as a grape.Not able to fly, ticks move slowly on the ground, or settle on tall grass.

Tick bites are usually painless, so you may not know you’ve been bitten. That's why it's important to take steps to protect yourself, and to be on the lookout for ticks and the symptoms of Lyme disease or other tick-borne diseases.

A tick bite doesn’t always result in disease. A tick has to be infected with bacteria or parasites in order to pass an infection on to you. The risk of getting a tick-borne disease from a tick bite is believed to be greater if an infected tick has been attached to you for more than 24 hours.