1. Epidemiology Department, Community Health Division, International Centre for Diarrhoeal Disease Research, GPO Box 128, Dhaka-1000, Bangladesh
2. Institute of Post-Graduate Medical Research, Dhaka, Bangladesh
3. Dhaka, Bangladesh
4. US Embassy Medical Unit, Dhaka, Bangladesh
5. Bangladesh Armed Forces, Dhaka Cantonment
6. Hepatitis Branch, Division of Viral Diseases, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia 30333, USA