[1] Univ Maryland, Sch Med, Dept Epidemiol & Prevent Med, Baltimore, MD 21201 USA
[2] Menia Univ, Fac Med, Menia, Egypt
[3] NIAID, Hepatitis Viruses Sect, NIH, Bethesda, MD 20892 USA
[4] NIAID, Mol Hepatitis Sect, NIH, Bethesda, MD 20892 USA
[5] Assiut Univ, Fac Med, Dept Trop Med, Assiut 71516, Egypt
[6] Minist Hlth & Populat, Ctr Field & Appl Res, Qalyub, Egypt
[7] Menoufia Univ, Liver Inst, Shibin Al Kawm, Egypt
[8] WHO, Dept Communicable Dis Surveillance & Response, CH-1211 Geneva, Switzerland