1. Research Center for Infectious Diseases, University of Würzburg, 97080 Würzburg, Germany
2. Department of Veterinary Sciences, Experimental Parasitology, Ludwig-Maximilians-Universität München, 80752 Munich, Germany
3. Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany