[Parasitologic studies, diagnosis and clinical aspects of cercarial dermatitis--public health significance for bathing waters in temperate zones].

Abstract

Swimmer's dermatitides occurring in natural--accordingly polluted--waters are most probably of chemical nature. In clean waters, however, they are primarily caused by larvae of duck-flukes, the so called cercariae. In a natural pool near Biberach undetermined cases of swimmers' dermatitis have appeared. Hence a cercarial dermatitis was suspected and specific examinations were carried out. At the biological examination of the pool, many watersnails of the species Radix ovata have been found near the shore. Out of 180 collected snails 8 produced cercariae of different trematode species. Hence an infective cycle between duck and snail could be ascertained here. However, the special cercariae, producing dermatitis, could not be found. Having taken that into account the author was standing in the snail biotop without protective clothes for about 1 hour to provoke cercarial dermatitis. A few minutes later the corresponding clinical picture with an extremely strong itching developed. Papules were to be seen 12 h later, the symptoms lasted 2 weeks altogether. By different serological methods (Cercarienhuellenreaction) indirect immunofluorescent test with complete cercariae and cercarial sections antibodies against cercariae could be demonstrated in the serum of the author 14 days later. As a therapy only the symptomatic treatment of the itching is possible. In principle etiologic measures against cercarial dermatitides are possible by chemical snail control. But as a rule this is to be refused because of the severe ecological damages. However, in case of swimmers' dermatitis it is nonetheless indispensible to clarify eventual parasitogenic reasons because of the specific hygienic consequences.