It's tick season and their numbers are on the rise

GUELPH – Wellington-Dufferin-Guelph Public Health (WDGPH) is finding more ticks overall, and in places they’ve never found them before.

And that, in turn, is causing more cases of Lyme disease.

Operations director of health protection Phil Wong and environmental health specialist Tyler Black presented the 2025 tick and mosquito surveillance findings at the April 1 board of health meeting and cautioned that the first confirmed black legged tick has already been identified this year.

Black legged ticks are known vectors of Lyme disease and there were 46 confirmed or suspected cases of it in 2025 among residents in the WDGPH region – up from 32 in 2024.

Increased tick activity has led to the expansion of Ontario risk zones that now include southern Wellington County, Guelph and most of Dufferin County, Black told the board.

While public health uses a method called dragging to identify where ticks are located, they only do that on public property.

In 2025 ticks were found in Hockley Valley Provincial Nature Reserve, Starkey Hill Conservation Area in Puslinch and Preservation Park in Guelph.

WDGPH also has an online tick identification tool, and 260 submissions were received in 2025 – a 25 per cent increase over 2024.

Many of the ticks were found on rural private property in north and central Dufferin County.

“These results indicate that the [WDGPH region] may be transitioning from a low-risk zone to one with established endemic transmission of tick-borne pathogens, highlighting the need for sustained, proactive surveillance and timely public education to help residents recognize, prevent and respond to tick exposures,” Wong’s report states.

“Dog surveillance data shows substantially higher seropositivity (presence of antibodies) for Borrelia burgdorferi (a bacterium that causes Lyme disease) among dogs in the L9V postal code area – covering parts of Mono, Melancthon and Mulmur – compared with the rest of [the region].”

This points to the need for targeted prevention and awareness efforts in those communities, especially for dog owners, the report notes.

Mosquito surveillance in 2025 also found West Nile Virus in Wellington North and Centre Wellington and WDGPH continues to apply larvicide to roadside catch basins in the region.

The report states WDGPH's pro-active approach to these diseases includes:

• targeted and expanded surveillance in rural areas and public-use greenspaces newly identified as risk zones;
• recognizing many tick-borne infections are suspected to be acquired on rural private properties and therefore strengthening partnerships with rural municipalities and agricultural communities to enhance awareness, reporting and prevention;
• continued surveillance for Borrelia, Babesia, Anaplasma and other emerging tick- and mosquito-borne pathogens, ensuring local data supports timely public health action; and
• continued training of professionals and engagement of youth through school-based citizen science initiatives and partnerships with the University of Guelph and Public Health Agency of Canada.

As tick and mosquito season arrives, public health is offering the following advice to area residents:

• wear light-coloured clothing so ticks are easy to see;
• cover up by wearing closed footwear and tucking pants into socks;
• use a repellent that contains DEET or picaridin and follow the manufacturer’s directions; 
• perform full-body checks for ticks on yourself, children and pets; and
• when you get home, put your clothes in the dryer on high heat for at least 10 minutes before washing them. 

For more information, visit wdgpublichealth.ca.