Swimmer's Itch - Control Measures and Treatment

Control Measures and Treatment

Various strategies, targeting either the mollusc or avian hosts of schistosomes, have been used by lakeside residents in recreational areas of North America to deal with outbreaks of swimmer's itch. In Michigan, for decades authorities used copper sulfate as a molluscicide to reduce snail host populations and thereby the incidence of swimmer's itch. The results with this agent have been inconclusive, possibly because:

• snails become tolerant
• local water chemistry reduces the molluscicide's efficacy
• local currents diffuse it
• adjacent snail populations repopulate a treated area.

More importantly, perhaps, copper sulfate is toxic to more than just molluscs, and the effects of its use on aquatic ecosystems are not well understood.

Another method targeting the snail host, mechanical disturbance of snail habitat, has been also tried in some areas of North America and Lake Annecy in France, with promising results.
Some work in Michigan suggests that administering praziquantel to hatchling waterfowl can reduce local swimmer's itch rates in humans. Work on schistosomiasis showed that water-resistant topical applications of the common insect repellent DEET prevented schistosomes from penetrating the skin of mice. Also 0.1-1% niclosamide formulation in water resistant sun cream or Safe SeaTM cream protecting against jelly fish stings were shown to be highly reliable protectants, having lethal effect on schistosome cercariae. Public education of risk factors, a good alternative to the above-mentioned interventionist strategies, can also reduce human exposure to cercariae. Experience at Higgins Lake, Michigan, where systematic research on Swimmer's Itch was conducted in the 1990s, shows that periodic brisk toweling of the lower extremities is effective in preventing Swimmer's Itch.

Orally administered hydroxyzine, an antihistamine, is sometimes prescribed to treat swimmer's itch and similar dermal allergic reactions.