The Thunder Bay District Health Unit has begun receiving phone calls from people wanting information about swimmer's itch.
The condition is caused by an allergic reaction to parasites released by infected snails. The parasites get into the skin and quickly die, but swimmers may feel tingling, burning or itching of the skin for a week or more.
Officials with the Health Unit advise people to towel off and shower as soon as possible after swimming in lakes and rivers in order to avoid the rash.
And if you have swimmer's itch, they advise applying cold compresses, baking soda paste or anti-itch lotion to the affected area.