Molecular Epidemiology of Hepatitis B Virus in the United Republic of Tanzania

Muhimbili University College of Health Sciences, Dar Es Salaam, TanzainiaIntheUnitedRepublicofTanzania,457voluntaryblood donors were enrolled in hepatitis B virus(HBV) serological screening; 4.8% (22/457)carried HBsAg, 13.6% (3/22) of whom wereHBeAg-positive. The mean age among HBeAg-negative carriers was 31 years. HBV DNA wasdetectable in 81.8% (18/22), the mean levelwas 1.94 ( 1.68) log copies/ml. Genotype A wasdetermined in 90.9% (20/22) and 18/20 wereclassified into subgenotype Aa (Asia/Africa).The basal core promoter, precore and partialcore nucleotide sequences were analyzed in the18 strains; T1809/T1812 (‘‘Kozak’’ sequence)and A/T1888 (encapsidation signal) variantswere identified in 100% and 78%, respectively.The complete genome sequencing for one oftheTanzanianstrainsrevealednorecombination.In conclusion, HBV seroprevalence is highamong general population in Tanzania, and theHBV/Aa-infection is predominant. The indicatedtendency to early HBeAg seroconversion anddeclining of the viral load should be confirmedfurther in case-control studies. J. Med. Virol.00:1–8, 2006.