To investigate genotypes of HBV and the viral population

in vivo

in young women

we collected serum samples from 24 cases HBV carriers of 19~35 years old young women with both HBsAg and HBeAg positive. Twentyfour samples were tested 14 genotype B

9 genotype C and one B/C genotypes co-infection. Nucleic acid extracts from 14 serum samples were used to amplify HBV large S protein genes through specific PCR. The amplification products were cloned and ten positive clones of each sample were selected for sequencing. The results confirmed that the 14 samples’ genotype were same. The case of B/C genotypes co-infection was a patient accepted adefovir antivirus therapy for 35 weeks. Four of the ten sequences were of genotype B with D

A

2.8. The other six sequences were of genotype C with D

A

0.6. There were three serotypes among the ten sequences through “α”determinant analysis. Population analysis suggested that the main genotypes of HBV infected young women in this region were B and C. HBV

in vivo

might distribute in a complex mode constructed with genotypes as well as quasispecies.