Cercarial dermatitis in Austria: questionnaires as useful tools to estimate risk factors?

Cercarial dermatitis is a worldwide occurring skin disease characterized by itching and skin papulation. It is caused by cercariae of the fluke family Schistosomatidae. In the tropics and subtropics species of the genus Schistosoma can cause severe diseases of man. However, several genera (e.g. Trichobilharzia, Bilharziella) of medical significance are prevalent in Europe as well; they are also known as "bird schistosomes", because waterfowl is the final host. Pulmonate snails act as intermediate hosts. Humans are accidental hosts; they get infested by penetration of the cercariae into the skin of swimmers/bathers in ponds and lakes. They can not mature in humans, but die shortly after penetration. Cercarial dermatitis is known in Austria since 1969, with regularly occurrences nearly every summer. In early 2003 we created a homepage to provide information about the causative agents for the public/patients, to document the occurrences and to get data about the distribution of this parasitic disease. We therefore created a questionnaire and asked people for the following parameters: personal data, information about the waters, activity in the water and details about the dermatitis itself. A total of 34 questionnaires were returned. The results will be discussed according to their relevance as risk factors. The way how people interact with the water seems to be essential, but not demographic features. In addition, this approach revealed a new segment of the public that is at risk - owners/users of swimming ponds.