Cercarial Dermatitis in Schleswig-Holstein Distribution of Cercariae in Public Swimming Lakes

Abstract

Cercarial dermatitis is a neglected zoonotic disease with distribution all over the world’s temperate zones. It is caused by cercariae, a larval stage of parasitic blood flukes of the genus Trichobilharzia that is a parasite of waterfowl. When cercariae burry into human skin, they trigger an allergic reaction that leads to severely itching papules. Goal of this research was to get an overview over the distribution of cercariae in the bathing places of Schleswig-Holstein, the most northern state of Germany. Therefore, all public bathing places were visited and searched for fresh water snails that are the potential intermediate hosts of cercariae. Water snails of different families and genera were collected and examined for the presence of cercariae. Water samples were taken and examined for cercariae via a microscope. Additionally slime samples of the water snails were taken to test a new, time saving method of detection. In total 8 different kinds of water snails were collected and examined, of which the families of Lymnaeidae and Planorbidae proved to be the most common hosts of cercariae. In total, the results indicate a spatial distribution of cercariae shedding snails all over Schleswig-Holstein.