1. Department of Public Health, College of Medicine and Health Sciences, Wachemo University, Hosaena, Ethiopia
2. Department of Public Health, College of Health Science, Debre Berhan University, Debre Birhan, Ethiopia
3. Department of Environmental Health, College of Medical and Health Science, Hawassa University, Awasa, Ethiopia
4. Department of Public Health, College of Life Sciences, Brigham Young University, Provo, USA