A swim in Lake Champlain on a hot, late-summer day can cause many things: happiness, a sense of well-being, and for some people, an itchy rash. Over the last few weeks, at least a dozen swimmers in the Charlotte and Shelburne area, many at the Charlotte Beach, have experienced an unfortunate side-effect of enjoying the town’s lovely beach.
Swimmer’s itch, or cercarial dermatitis, is an allergic reaction to a parasite that thrives in certain conditions and can be found in lake water. Other than an ick factor, there is no danger or health concern from this parasite or rash. When the water is warm, a parasite can thrive in and attempt to burrow into people’s skin. Though the parasite cannot survive in humans, their burrowing can cause an allergic reaction, which manifests as a rash.
Neil Kamman, Program Manager at the Vermont Department of Environmental Conservation Watershed Management Division, said, “Swimmer’s itch is actually the result of a naturally occurring parasitic organism that in its normal life cycle alternately inhabits snails, or the legs of swimming ducks. Thus, if you have snails (which are naturally occurring), and ducks (which are also naturally occurring), you may have the presence of swimmer’s itch.”
Kamman said that there is no office that regulates or tracks instances of this parasite, but that in extreme circumstances, control of one or the other of the host organisms could be warranted. He also said that in Lake Champlain, not much could be done to stop the parasite’s life cycle, but that perhaps not feeding the ducks and making the area less appealing to them might help.
The Charlotte Beach is a prime breeding ground for the parasite. Eric Howe, an environmental analyst and the Lake Champlain Basin Program Technical Coordinator, said people swimming in shallow, warm water that’s recently been visited by a large flock of ducks or geese, or is near a marshy area that also has a lot of snails, are most susceptible to intercepting the parasite as it passes through the snails and moves out into the water column.
Though there is no way to completely prevent the parasites from attempting to burrow into your skin, he recommends thoroughly toweling off immediately after getting out of the water, which removes the parasites from your skin. Both Howe and Kamman note that the parasite is not only common in Lake Champlain, but is found all over the world.
Though the rash is not contagious, and poses no long-term health issues, it is an itchy, uncomfortable condition. People afflicted can manage their symptoms with anti-itch cortisone cream, Benadryl, oatmeal baths, and other typical remedies for an uncomfortable rash. For more information about the parasites, or cercarial dermatitis, visit http://www.cdc.gov/parasites/swimmersitch/faqs.html.