1. Small Animal Clinic, Free University of Berlin, Oertzenweg 19b, 14163 Berlin, Germany
2. Small Animal Clinic, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 23, 04103 Leipzig, Germany
3. Department of Clinical Sciences of Companion Animals, University of Utrecht, PO Box 80.154, 3508 Td, Utrecht, The Netherlands
4. Institute for Veterinary Pathology, Department of Veterinary Medicine, Free University of Berlin, Oertzenweg 19b, 14163 Berlin, Germany