1. Department of Medical Parasitology, Clinical Institute of Hygiene and Medical Microbiology, Medical University of Vienna, Kinderspitalgasse 15, 1095 Vienna, Austria
2. Central Institute of the Federal Armed Forces Medical Services, Department of Parasitology, Andernacher Straße 100, 56070 Koblenz, Germany
3. Department of Ecology and Limnology, Institute of Zoology, University of Cologne, Weyertal 119, 50923 Cologne, Germany