1. Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2. Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
3. Department of Epidemiology and Biostatistics, School of Health, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran