Sequence analysis of the polymerase gene in hepatitis B virus infected blood donors in Iran

ABSTRACT

Hepatitis B is one of the most common infectious diseases worldwide that can be transmitted by blood transfusion. The hepatitis B virus [HBV] has eight different genotypes that show different geographical distributions and clinical manifestations. This study aims to investigate the sequence of the HBV polymerase gene and the frequency of HBV genotypes among Iranian blood donors. The sera of 223 blood donors who were positive for hepatitis B surface antigen [HbsAg] as determined by the ELISA method were selected. HBV DNA was extracted from the sera of 134 blood donors by a commercial kit, and the entire polymerase gene was amplified by nested-PCR. HBV genotypes were determined by direct sequencing of the HBV polymerase gene. Phylogenetic trees were constructed by the neighbor-joining [NJ] method. No known base mutations were found in the entire HBV polymerase gene of infected blood donors, and only genotype D was detected among HBV-infected blood donors. The sub-genotype D1 of HBV was dominant in the subjects. This study shows that antiviral-resistant mutations, such as lamivudine-resistant HBV strains, do not exist naturally among Iranian blood donors. More studies on the full-length HBV genomes are required to determine genome evolution of HBV among infected Iranian blood donors