With summer approaching, more Quebecers are heading outdoors -- but health authorities are issuing a warning about Lyme disease because of an increase in ticks.

In the Montérégie region, public health says there's been a 50 per cent increase in cases.

"If we talk about Montérégie, ticks are present in the whole region," said Dr. Francois Milord, a Lyme disease expert and consultant for the department.

The disease is carried by these ticks. When they bite humans, they spread a bacteria into the bloodstream, which can cause fatigue, aches and a sore throat.

The most telling sign is a rash that looks like a bullseye.

"It's a redness that will increase over a few days and be over five centimetres," said Dr. Milord.

Left untreated, Lyme disease can lead to more serious problems affecting the nervous system.

If you think you've been bitten by a tick, doctors say the first thing to do is remove it before seeing a pharmacist who can prescribe the antibiotic Doxycycline.

Last month, the Quebec government announced it will open 15 specialized clinics that will focus on long-COVID and Lyme disease.

Experts have also pointed to a link between climate change and ticks, as warmer weather helps them survive and reproduce.

"Longer summers mean we have a longer period of time where ticks are active and people are outdoors. So it's increasing the window of opportunity where these two are going to come into contact with each other," said Jill Baumgartner, a professor in McGill University's epidemiology department.

Animals like birds, mice and deer can carry the ticks, and their loss of habitat may also be driving the spread.

"This increases both the transport of these ticks, so these animals can move these ticks over long distances, and this puts humans at risk," Baumgartner said.

There are steps to protect yourself from Lyme disease: wear long, light-coloured clothing, stick to trails while hiking, check yourself and others for ticks, and take a hot shower after spending time in wooded areas.