Mapping Swimmer’s Itch Across Alberta

Many of us have had it.


I’m talking about the red, itchy rash we sometimes get after swimming in a lake.

Commonly called “Swimmer’s Itch,” Alberta has seen a considerable rise in the amount of cases reported this year.

Swimmer’s Itch is caused by the small larvae of parasites, known as schistosomes, which are transported by infected snails and deposited into fresh and salt water. These parasites are found in lakes and ponds across Alberta and the rest of Canada.

When the schistome larvae come into contact with your skin, they can penetrate the surface and cause your body to have an allergic reaction in the form of a red, bumpy rash. The rash can last up to two weeks (and will probably drive you crazy).

This summer, Alberta has seen more outbreaks of swimmer’s itch than normal, but it isn’t entirely clear why or how many people are affected each year. This has made it challenging for Alberta Health Services (AHS) to notify swimmers when and where there is a high risk of an outbreak.

This year, AHS teamed up with the School of Public Health at the University of Alberta to dig deeper into the life history and range of this common parasite. Through research and surveys, they’re mapping Swimmer’s Itch in our province. Eventually, the researchers are hoping to be able to predict where and when outbreaks will be the most prevalent. They’ve come up with this risk map, which they’ve put together with the help of swimmers like you documenting when and where they came into contact with the parasite.


Have you had swimmer’s itch? Some of the symptoms include the following:

  • tingling, burning, or itching of the skin
  • small, reddish pimples
  • small blisters

Often, the rash will go away gradually in a week or so, but itching the affected area can cause pimples to develop into small blisters. To learn more, you can read the U of A FAQ on Swimmer’s Itch here.


You can support this project, and help keep Albertans informed, by filling out this survey.



Swimmer’s Itch.