Besides the heat and drought-like conditions, swimmer's itch has been a hot topic this summer in Alberta! If you are unfamiliar, swimmer's itch is an allergic skin rash caused by skin penetration from flatworm parasites (trematodes) that naturally infect snails and birds in aquatic ecosystems. 

The rash can be incredibly itchy and easily ruin a vacation, but does not have long-lasting ill health effects. Through the use of our online survey at swimmersitch.ca, we've received over 243 swimmer's itch reports from across Canada this summer, so far, and a previous 436 reports from the previous two summers. We now have a pretty good idea of how many lakes are affected in Alberta and other parts of the country, but as word about the website increases, so does our view of just how expansive this condition really is.

In addition to collecting surveys from swimmer's about their most recent case of the itch, we have been conducting a multi-year, longitudinal survey to sample aquatic snails across six central, high-use, recreational lakes in Alberta: Lake Isle, Lac la Nonne, Wabamun Lake, Pigeon lake, Buffalo Lake, and Gull Lake. Over the past two years, we have learned that there are three primary snail species that host at least five different species of schistosome (trematodes known to cause itch). In addition, we have found over 30 other trematode species that infect five snail species at these same lakes, which has huge implications for how likely or unlikely it is to find a swimmer's itch causing parasite. We are currently in the process of collecting more snails to look for parasites this summer at the same lakes so we can look for trends across a three year data set. Currently, we are summarizing the data from the past two summers in a report to be submitted for publication later this month. 

So, why does swimmer's itch occur where it does? And how do we know when it is risky to swim? Well, answering these questions is the focus of my Ph.D. research. I want to understand when and where swimmer's itch occurs, who the culprits are (as in snail and parasite species), and what environmental (or other) factors may be used as indicators of peaks in transmission. The ultimate goal will be to predict peak transmission periods and communicate this to swimmers and other lake users.