1. Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
2. Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
3. Helicobacter pylori Research Group, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
4. Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran