1. Centre for Fish and Wildlife Health, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, Postfach 8466, 3001 Bern, Switzerland
2. Institute of Parasitology, Vetsuisse and Medical Faculty, University of Zürich, Winterthurerstrasse 266A, 8057 Zürich, Switzerland
3. Department of Clinical Research & Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3001 Bern, Switzerland