1. Public Health Engineer, Enteric Diseases Epidemiology Branch, Centers for Disease Control and Prevention, 1600 Clifton Rd., MS-A38, Atlanta, GA 30333 (corresponding author).
2. Research Assistant, Dept. of Civil and Environmental Engineering, Lehigh Univ., 13 East Packer Ave., Bethlehem, PA 18015.
3. Surveillance Epidemiologist, Enteric Diseases Epidemiology Branch, Centers for Disease Control and Prevention, 1600 Clifton Rd., MS-A38, Atlanta, GA 30333.
4. Marketing and Communication Director, Population Services International, Gambia/Meskel Flower Rd., Addis Ababa, Ethiopia.