1. Department of Pharmacology, Animal Physiology and Physiological Chemistry, Faculty of Veterinary Medicine, Trakia University, Student's Campus, 6000 Stara Zagora, Bulgaria
2. Institute of Experimental Pathology and Parasitology, Bulgarian Academy of Sciences, Acad G.Bonchev Street Bl. 25, 1113 Sofia, Bulgaria
3. Department of Veterinary Microbiology, Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, Trakia University, Student's Campus, 6000 Stara Zagora, Bulgaria