What to know about Lyme disease amid ‘steady increase’ in Canada, U.S.

Justin Timberlake is the latest celebrity to announce he has been battling the 'relentlessly debilitating' disease, which can cause severe symptoms that can persist for years.

Cases of Lyme disease have been building steadily in Canada and the U.S. over the past few years, with the infectious tick-borne illness once again making its way into international headlines.

Justin Timberlake last week became the latest celebrity to announce he has been battling the “relentlessly debilitating” disease, which causes sometimes-severe symptoms that can persist for years.

Other high-profile cases in recent years include the Canadian musicians Justin Bieber, Avril Lavigne and Shania Twain.

Lyme disease is passed on to humans through the bites of infected ticks, which thrive in warmer temperatures. Climate change and shifting weather patterns have created more favourable conditions for ticks beyond just the hot summer months, and has also allowed ticks to expand their habitats across Canada, bringing them into closer contact with humans and animals.

Health Canada warns that ticks can be active whenever the temperature stays above freezing and the ground isn’t snow-covered, creating a year-round risk.

“There has been a steady increase in the number of Lyme disease cases in Canada, primarily because the geographic range of ticks has changed over the last 20 years,” a Public Health Agency of Canada (PHAC) spokesperson told Global News in an email.

The latest national Lyme disease data shows there were 5,239 reported cases in Canada in 2024. However, PHAC says this preliminary count is likely an underestimation of the final total.

A decade ago, there were only 522 reported cases in 2014.