​Public health warns of additional “Black-legged Tick Established Risk Area”

Grey Bruce Public Health encourages residents and visitors to take steps to prevent tick bites while outdoors, particularly in locations where ticks typically live, such as in, or near, wooded or bushy areas, tall grass, or piles of leaves.

This annual reminder, which follows the return of warmer weather in Grey-Bruce, coincides with the release of Public Health Ontario’s 2024 Ontario Black-legged Tick Established Risk Areas Map, formerly the Ontario Lyme Disease Map: Estimated Risk Areas.

The updated map includes a new ‘Estimated Risk Area’ in Grey-Bruce – a location where black-legged ticks, which can transmit the bacteria that causes Lyme disease to people, have been identified or are known to occur and where people could encounter them. The new ‘Estimated Risk Area,’ in central Grey-Bruce, brings to four the total number of such risk areas in the two counties.

“It’s important to stress that these are estimated risk areas only and infective black-legged ticks can be found pretty much anywhere in Ontario, especially if the habitat is ideal for these poppy-seed-sized arachnids,” says senior public health manager Andrew Barton. “Because of this, people should take precautions to prevent tick bites whenever they’re enjoying the outdoors. Preventing tick bites is the best way to prevent Lyme disease.”

Lyme disease, a relatively rare vector-borne illness in Canada, is caused by the bacterium B. burgdoferi, which black-legged ticks can carry. People can get Lyme disease if an infected black-legged tick bites and then feeds on them long enough to transmit the bacteria – in most cases, this takes at least 24 hours.

Not all black-legged ticks carry the bacteria and not everyone who is bitten by an infected tick will develop signs and symptoms of Lyme disease.

In 2022, there were 1,490 cases of Lyme disease throughout Ontario, which represents a rate of 9.9 cases per 100,000 people.

The updated Ontario Black-legged Tick Estimated Risk Areas 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 black-legged tick bites.

Estimated risk areas are calculated as a 20-kilometre radius from the centre of a location where black-legged ticks were found through drag sampling. The new estimated risk area in Grey-Bruce was established in response to the results of public health’s 2023 tick surveillance.

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
• Checking your full body, children, gear, and pets for ticks

If bitten by a tick, remove it immediately. Information on how to remove and identify a tick can be found on Health Canada’s Lyme Disease web page.

Early Lyme disease symptoms can include fever, headache, muscle/joint pain, fatigue, and a bull’s-eye rash. Residents should consult a health-care 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 here. Public health follows up with all residents diagnosed with Lyme disease.