(NC) Those of us in Ontario are fortunate to have an abundance of wilderness to explore. But one thing to keep in mind when outside is Lyme disease, as health officials are seeing an increase in the number of cases in the province.

“The number of confirmed cases of Lyme disease has been rising since 2011,” says Dr. David Williams, Ontario’s chief medical officer of health. “This is partly due to an expansion of black-legged tick populations to new areas of the province, especially in wooded areas.”

Lyme disease is a serious illness spread to humans through the bite of an infected black-legged tick. Williams says that in most cases, the tick must be attached for at least 24 hours for the Lyme disease bacterium to be passed on to the host.

Black-legged ticks cannot fly, but settle on grass and bushes until they attach themselves to a person or animal so it’s a good idea to be particularly careful in areas that are forested or have tall grass, weeds or many shrubs. The ticks are also known to feed on migratory birds and can be carried throughout the province.

The most commonly known symptom of Lyme disease is an expanding skin rash. The rash can begin at the site of the tick bite between three and 30 days after exposure and usually grows for several days. But many people never get or see a rash.

If the disease is left untreated, other symptoms may develop in the weeks following exposure, including rash, fever, chills, headache, fatigue, muscle and joint aches, and problems with heartbeat, breathing, balance and short-term memory. In rare cases Lyme disease may result in death.

“It is important to see your healthcare provider as early as possible if you have symptoms or if you feel unwell in the weeks following a tick bite,” advises Williams. “The earlier treatment is received the better.”

Lyme disease is not transmitted from person-to-person. However, dogs and cats can carry the ticks into your home and place families at risk of being bitten. Check your pets for ticks daily and talk with your vet about keeping your pet protected from ticks. If your pet is found to have a tick, remember that you, too, are at risk when spending time in the same outdoor environments.

Talk to your healthcare provider or local public health unit and learn more online at ontario.ca/lyme.