1. Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran
2. Academy of Medical Sciences, Tehran, Iran
3. Digestive Disease Research Center, Shahriari Hospital, Tehran University of Medical Sciences, Tehran, Iran
4. School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
5. Health Policy Research Center, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran
6. School of Medicine, Iran University of Medical Sciences, Teheran, Iran
7. Ridgeway, Ontario, Canada, LOS 1N0