Incredibly, this report notes that over 50% of the 55,000 visitors to this lake in the summer of 1933 had contracted swimmer’s itch. In Canada, the first report and confirmation of the etiological agent of swimmer’s itch, also commonly referred to as ‘schistosome dermatitis’ in the literature, was by McLeod in 1934 at Clear Lake, Manitoba. Ī review of the literature exposes the marked historical presence of swimmer’s itch across most of Canada for nearly a century. Trichobilharzia species utilize waterfowl as a definitive host in which they mature into adult worms, while Schistosomatium species utilize small, aquatic mammals. Īlthough schistosomes in general are noted to cause dermatitis, it is those of the genera Trichobilharzia and Schistosomatium that are most notably the etiological agents in freshwater ecosystems in North America. Swimmer’s itch has been noted to occur in both fresh and saline waters, though it is caused by different schistosome genera cycling through different genera of snail hosts.
#SWIMMERS ITCH PARASITES SKIN#
For example, in 1887, skin conditions resembling cercarial dermatitis were described among Japanese rice farmers, referred to locally as ‘koganbyo’ or ‘lakeside disease’ (other names reviewed in ). Even before Cort’s discovery, cercarial dermatitis was informally described using a variety of names. Cort found that it was the larval cercarial stage of avian schistosomes (parasitic flatworms) emerging from their snail host that caused the rash by penetrating the skin, and he described the condition as cercarial dermatitis. Cort at Douglas Lake, Michigan, when handling snails during collections resulted in the development of a rash. Nearly 100 years ago, the cause of swimmer’s itch was discovered by Dr. Swimmer’s itch is an allergic rash contracted when swimming in natural water bodies and is by no means a new condition, as historical reports from the literature suggest a global distribution. Recommendations are made towards implementing a systems-thinking approach that incorporates citizen-scientists for future research, management, and policy surrounding swimmer’s itch.Ĭercarial dermatitis, or ‘swimmer’s itch’, is often referred to as an emerging disease, despite the fact there are no data tracking the number of afflicted people. This study provides proof-of-concept for the utility of a self-reporting surveillance system for swimmer’s itch in Canada. Swimmer’s itch is a greater environmental health hazard across Canada than previous literature would have alluded. A review and comparison to the literature has highlighted several knowledge gaps surrounding schistosome species, host species and their distributions and contributions towards swimmer’s itch. Species surveys in Alberta revealed 7 new parasite and host records, with potential for swimmer’s itch to occur throughout most of the province based on host distributions. Swimmer’s itch cases were reported from every province except Prince Edward Island. Over 3800 cases of swimmer’s itch were captured across Canada by the self-reporting surveillance system. We compare the results from our surveys to a historical review of the literature to examine the extent of swimmer’s itch across Canada and identify where future efforts should be focused. We also conducted a 3-year species survey of parasites and intermediate snail hosts within lakes in central Alberta and compiled this data with snail and vertebrate (definitive) host survey data from across Alberta to examine potential for future spread. We examine the human perspective of having contracted swimmer’s itch through a self-reporting surveillance system implemented over a 5-year period. Herein we utilize a mixed-methods approach towards examining the environmental health issue of swimmer’s itch in Canadian lakes from a nation-wide viewpoint, with an example from Alberta. This study aims to gather relevant information on swimmer’s itch in Canada, from multiple perspectives, including the human experience, parasite and host presence and distributions, and insight from historical perspectives. Swimmer’s itch is a globally-distributed, allergic condition, of which we know very little regarding local dynamics of transmission. Cercarial dermatitis, colloquially “swimmer’s itch”, is a rash contracted in natural bodies of water, when people are exposed to skin-penetrating, larval flatworm parasites of the family Schistosomatidae, that emerge from aquatic snails.
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