An adult female blacklegged tick, sometimes known as a deer tick. Photo by Erik Karits on Unsplash.

Two more parts of Grey-Bruce are now considered estimated risk areas for Lyme disease due to the discovery of blacklegged ticks, sometimes known as deer ticks, which can carry the bacteria that causes the relatively rare vector-borne illness.

In a June 1 media release from Grey Bruce Public Health, Public Health Ontario recently released its 2023 Ontario Lyme Disease Map, which identifies estimated risk areas in the province; locations where blacklegged ticks, which transmit the disease, have been identified or are known to occur and where people could encounter them. The Ontario Lyme Disease Map informs the public about these areas so they can take precautions.

Estimated risk areas are calculated as a 20-kilometre radius from the centre of a location where blacklegged ticks were found through drag sampling. As a result of GBPH’s tick surveillance in 2022, two new estimated risk areas have been identified in Grey-Bruce, bringing the total number in the two counties to three.

The areas, which overlap and are each in the western part of Grey-Bruce near the Lake Huron shoreline, include parts of Northern Bruce Peninsula, South Bruce Peninsula, Georgian Bluffs, Saugeen Shores, Arran-Elderslie, and Kincardine.

“While the risk of getting Lyme disease remains low, we’re asking residents to take simple measures to protect themselves from tick bites while enjoying the outdoors. It is important to be aware of the areas where blacklegged ticks are known to live or in potential tick habitat, such as wooded areas, shrubs, tall grass, or leaf piles,” said GBPH Senior Program Manager Andrew Barton.

Lyme disease is caused by the bacteria B. burgdoferi, which can be transmitted to a person by the bite of an infected blacklegged tick.

The chance of encountering a blacklegged tick in Grey-Bruce has increased over the years, along with the number of Lyme disease cases in Ontario. Not all blacklegged ticks carry the bacteria that causes Lyme disease and not everyone who is bitten by an infected tick will develop signs and symptoms of Lyme disease.

In 2021, there were 1,455 cases of Lyme disease across Ontario, which represents a rate of 9.6 cases per 100,000 people.

There’s a possibility of encountering infective blacklegged ticks almost anywhere in Ontario as ticks feed on and are transported by animals and migratory birds.

The Ontario Lyme Disease Map assists Public Health Units as they conduct Lyme disease case investigations and provides primary care providers with valuable information when considering potential exposures to blacklegged tick bites.

Early Lyme disease symptoms can include fever, headache, muscle and joint pain, fatigue, and a bull’s-eye rash. Residents should consult a healthcare provider if experiencing these symptoms. If caught early, Lyme disease can be effectively treated with antibiotics.

Eligibility information for post-exposure prophylaxis to prevent Lyme disease is available at hqontario.ca/Portals/0/documents/evidence/qs-lyme-disease-clinical-guidance-2023-en.pdf. GBPH follows up with all residents diagnosed with Lyme disease.

The best way to prevent Lyme disease is to avoid tick bites by:

Using bug repellent containing DEET or Icaridin;
Wearing light-coloured clothing;
Tucking your shirt into pants, pants into socks, and wearing closed-toe shoes;
Walking on clear paths;
Using a sticky roll brush to remove ticks from clothing before getting into the car;
Showering or bathing shortly after being outdoors; and
Checking your full body, children, gear, and pets for ticks.

If bitten by a tick, remove it immediately. In most cases, infected ticks must be attached to a person for at least 24 hours to pass on the bacteria. Information on how to remove and identify a tick can be found at canada.ca/en/public-health/services/diseases/lyme-disease/removing-submitting-ticks-testing.html#a4.