title: Molecular epidemiology of hepatitis B virus isolated from Bangladesh.
abstract: BACKGROUND
  Hepatitis B virus (HBV) is highly contagious and causes liver diseases. Globally more than 350 million people are chronically infected and among them above 80 % are from developing countries like Bangladesh. Resistance to existing drugs and vaccines are common phenomenon due to mutations in HBsAg 'a' determinant. Due to lack of data about mutations and subtypes of HBV in Bangladesh, this study strongly demands to be documented. Here, we determined the genotypes and subtypes of HBV prevalent in Bangladesh, and their genomic mutations associated with vaccine and drug resistance.
  
  
  RESULTS
  Among 385 samples, a total of 54 (14 %) were found HBV positive, of which 19 samples were subjected to be sequenced. After bioinformatic analysis, we found Genotype D as predominant genotype (73.7 %) with subtypes ayw3 (64.3 %) and ayw2 (35.7 %), followed by genotype A with subtype adw2 (15.8 %), and then genotype C with subtype adr (10.5 %). A significant number of mutations (Thr118Val, Thr125Met, Thr126Ile, Pro127Thr, Ala128Val, Thr131Asn/Ser, Thr/Ser143Leu/Met) were found in 'a' determinant region which may admit resistance to the available vaccines and failure of HBsAg detection.
  
  
  CONCLUSIONS
  This comprehensive study have clinical importance like disease diagnosis and treatment. It emphasizes HBV infected patients to do molecular diagnosis for choice of anti-viral drugs and effectiveness of vaccines for proper treatment.
authors.affiliation: Microbial Biotechnology Division, National Institute of Biotechnology, Savar, Dhaka, 1349 Bangladesh ; Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh.
authors.forename: Modhusudon
authors.initials: M
authors.lastname: Shaha
authors.affiliation: Cell and Tissue Culture Laboratory, Center for Advance Research in Sciences, University of Dhaka, Dhaka, 1000 Bangladesh.
authors.forename: Sheikh Ariful
authors.initials: SA
authors.lastname: Hoque
authors.affiliation: Microbial Biotechnology Division, National Institute of Biotechnology, Savar, Dhaka, 1349 Bangladesh.
authors.forename: Sabita Rezwana
authors.initials: SR
authors.lastname: Rahman
keywords: Bangladesh; Genotypes; Hepatitis B virus; Mutations; Partial S gene