Frequency and distribution of hepatitis B virus genotypes among eastern Indian voluntary blood donors: Association with precore and basal core promoter mutations.

Aim: To screen hepatitis B virus (HBV) genotypes and associated basal core promoter (BCP; T1762/A1764) and precore (PreC; A1896) mutations among the HBV surface antigen (HBsAg) positive voluntary blood donors in eastern India.

Methods: HBV genotypes, BCP and PreC mutations of 141 HBsAg positive voluntary blood donors were determined by the restriction fragment length polymorphism (RFLP) method and a phylogenetic tree was constructed from surface (S) gene region sequences of representative HBsAg positive donors to confirm the results.

Results: HBV/D was the most predominant (79, 56.0%) genotype followed by HBV/C (33, 23.4%) and HBV/A (29, 20.6%). HBV/C infected blood donors are mostly young (18-25 years). The occurrence of BCP mutation was found to be significantly higher in HBV/C (24, 72.7%) than in HBV/A (7, 24.1%, P < 0.001) and HBV/D (17, 21.5%, P < 0.001), whereas PreC mutation was more frequent in HBV/D (28, 35.4%) than in HBV/C (9, 27.3%). However, the simultaneous presence of BCP and PreC mutations was more common in HBV/C (8/33, 24.2%), followed by HBV/D (6/79, 7.6%).

Conclusion: In addition to HBV/D and HBV/A, a significant proportion of HBV/C (23.4%) was also present among the voluntary blood donors from eastern India, most frequently in the 18-25 year age group. BCP mutation was more common in HBV/C infected donors.