1. 1Department and Clinic of Internal Medicine, Faculty of Veterinary Science, Szent István University, P.O. Box 2, H-1400 Budapest, Hungary
2. 2Department of Biomathematics and Informatics, Faculty of Veterinary Science, Szent István University, P.O. Box 2, H-1400 Budapest, Hungary
3. 3Small Animal Clinic, University of Veterinary Medicine Hanover, Hanover, Germany