1. Department of Pathology, University of Khartoum, Khartoum, Sudan, USA
2. Department of Community Medicine, College of Medicine, University of Juba, Khartoum, Sudan, USA
3. Department of Surgery, University of Khartoum, Khartoum, Sudan, USA
4. Department of Parasitology, National Health Laboratory, Ministry of Health, Khartoum, Sudan, USA
5. USDepartment of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
6. National Institutes of Health, Bethesda, Maryland, USA
7. Department of Medicine, Faculty of Medicine, University of Khartoum, Khartoum, Sudan, USA