1. Department of General and Clinical Pathology, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
2. Department of Internal Diseases, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
3. Department of Biochemistry and Microbiology, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria