[Characterization and distribution of hepatitis B virus genotypes and subtypes in 4 provinces of China].

OBJECTIVE: To determine the distribution and genetic relationship of hepatitis B virus (HBV) genotypes and subtypes.
METHODS: HBV genotypes and subtypes were determined by PCR and DNA sequencing among 280 chronic HBV carriers in 25 counties of 4 provinces (Hunan, Guangxi, Henan and Hebei) in China.
RESULTS: Genotype B, C and D were detected in these regions. Genotypes C and B were the majority genotypes of HBV with 190 cut of 280 (67.9%) genotype C, 82 (29.3%) genotype B, and 8 (2.9%) genotype D. Adr, adw2, ayr, ayw1, ayw2 and ayw3 subtypes were determined among these carriers. Adr and adw2 subtypes were the leading subtypes of HBV, taking up 64.3% and 31.4%, respectively. Adr subtype was completely encoded by genotype C while majority of adw2 subtype was encoded by genotype B. An average rate nucleotide substitutions of 2.94 was seen among 280 Chinese HBV sequences. The average rate of nucleotide substitutions of genotype B (adw2 subtype) was 5.63 (5.48), but only 1.6 (1.51) for genotype C (adr subtype).
CONCLUSION: The results suggested that there were significant differences in geographic distribution of HBV genotypes and subtypes; genotype B, in which mostly consistent with adw2 subtype, was a higher variable than genotype C (adr subtype).