1. Federal Ministry of Health, Addis Ababa, Ethiopia;
2. School of Water and Public Health, Ethiopian Institute of Water Resource, Addis Ababa University, Ethiopia;
3. Public Health Department, College of Health Sciences, Mekelle University, Mekelle, Ethiopia;
4. Department of Medical Microbiology and Immunology, Institute of Biomedical Sciences, College of Health Sciences, Mekelle University, Mekelle, Ethiopia