1. Faculty of Medicine , Department of Internal Medicine, , Gama'a, 21111 P.O. Box 20, Wad Medani, Gezira , Sudan
2. University of Gezira , Department of Internal Medicine, , Gama'a, 21111 P.O. Box 20, Wad Medani, Gezira , Sudan
3. Department of General Surgery, King Salman bin Abdulaziz Medical City , 8004 Sulayman Bin Othman, 42319 Mahzur, Al-Medinah Al-Munawwarah , Saudi Arabia
4. Department of Clinical Science , Consultant of Community Medicine and Public Health, , Hejrah Street P.O. Box 41411, Al-Medinah Al-Munawwarah , Saudi Arabia
5. College of Medicine, Al-Rayan College , Consultant of Community Medicine and Public Health, , Hejrah Street P.O. Box 41411, Al-Medinah Al-Munawwarah , Saudi Arabia