Are you heading to the cottage and thinking about visiting parks and wooded areas? Maybe you fancy going hiking, golfing, hunting, camping, bird-watching, or fishing. Before you jump into this season’s fun, stay safe by checking out Ontario’s annual Lyme Disease Map for 2022: Estimated Risk Areas. The map highlights common high-risk areas, where blacklegged ticks (ticks that have the potential to carry the bacteria causing Lyme disease) are typically found. Many popular cottage spots are on the map.
What exactly is the Ontario Lyme disease map?
The Ontario Lyme disease map is released annually by Public Health Ontario in an effort to assist public health professionals and clinicians to make informed decisions on testing and treatment. According to Public Health Ontario, the risk areas are calculated “as a 20 km radius from the centre of the location where blacklegged ticks were found through drag sampling.” Drag sampling is a surveillance method which involves dragging a white flannel cloth over vegetation to determine if ticks are present. Public Health Ontario decides where to conduct drag sampling based on historical location data of black-legged ticks, assessment of exposure from local human Lyme disease cases, and evidence of suitable tick habitat. Drag sampling is completed over a three-hour period between May and October where ticks have previously been found, and is conducted twice a year where ticks have not been previously found.
If I’m not in a high-risk area, can I still encounter a blacklegged tick?
You may encounter an infected blacklegged tick almost anywhere in Ontario. They thrive alongside forest edges and in shrubs, leaf litter, wood piles, and long grass. These ticks also feed on and can be transported by migratory birds. The map is not intended to be a fulsome list of where black-legged ticks are found in Ontario, but rather to highlight high-risk exposure locations.
Is the problem getting worse?
While there is an uptick in trends of Lyme disease for all ages and sexes, according to Public Health Ontario, there was a decrease in cases from 2019 to 2020 (the last year of trend data) in Ontario. Moving to the broader Canadian scale, reported cases of Lyme disease did rise from 1,615 in 2019, to a preliminary case count of 2,851 in 2021.
There is minor variation in comparing the Ontario Lyme disease maps between the years of 2019-2022, however, similar estimated risk areas have been identified.