1. Department of Infectious Diseases; Hamadan University of Medical Sciences; Hamadan Iran
2. Brucellosis Research Center; Hamadan University of Medical Sciences; Hamadan Iran
3. Department of Infectious Diseases; Kermanshah University of Medical Sciences; Kermanshah Iran
4. Department of Immunology; Hamadan University of Medical Sciences; Hamadan Iran
5. Department of Community and Preventive Medicine; Hamadan University of Medical Sciences; Hamadan Iran