The present paper provides a review of the current literature regarding the molecular-based epidemiology of hepatitis B virus (HBV) and hepatitis C virus (HCV), which are very important viruses underlying the etiology of blood-borne infectious diseases worldwide. Particularly, both HBV and HCV are widespread on the Asian continent and are associated with acute and chronic liver diseases, including hepatocellular carcinoma. HBV has been classified into genotypes A through G and shown to have a distinct geographic distribution. In Asia, genotypes B and C of HBV prevail, and genotype C has been shown to cause more serious liver disease than genotype B. High prevalence of HBV mutants with various forms, such as the pre-S mutant, basal core promoter mutant, YMDD motif mutant and vaccine escape mutant, were seen in Asia and these were found to be related to the severity of liver disease and sensitivity to therapy. HCV has also been classified into multiple genotypes and associated with geographic distribution. HCV genotype 1 is less sensitive to interferon therapy and may be associated with the presence of more serious liver disease than the other genotypes. Data on the relation among the HBV/HCV genotypes, their pathogenicity in chronic liver diseases including hepatocellular carcinoma and their effect on therapy are awaited with great interest, especially in Asia, which is an endemic region of blood-borne hepatitis viruses.

Background: Although it is thought that Vietnam is a high endemic region of hepatitis A virus (HAV) infection, there is no report on genomic characterization of HAV spread in Vietnam. The purpose of the present paper was therefore to identify various virus infections from 33 children with acute or fulminant hepatitis of unknown etiology admitted to Children’s Hospital No.1 in Ho Chi Minh City, Vietnam.
Methods : Anti-HAV IgM and IgG were assayed by ELISA. Viral RNA and DNA were determined by PCR method.
HAV genes isolated by PCR were sequenced and characterized by phylogenetic analysis.
Results : Anti-HAV IgM was detected in 18 of 26 acute hepatitis (69.2%) and one of seven (14.3%) fulminant hepatitis patients. Furthermore, HAV-RNA in serum was identifi ed in fi ve of 26 acute (19.2%) and two of seven (28.6%) fulminant hepatitis patients, respectively, on nested reverse transcription – polymerase chain reaction . Among the seven HAVRNA-positive patients tested, two (28.6%) were negative for anti-HAV IgM. We also obtained seven isolates containing the HAV genome with the viral protein 1 (VP1) region sequence. All Vietnamese HAV isolates formed a cluster and belonged to genotype IA according to phylogenetic analysis based on the short sequences of VP1-2A junction region.
Conclusion : HAV is an important agent with regard to fulminant hepatitis among children in Vietnam. To the authors’ knowledge this is the fi rst report on Vietnamese HAV strain confi rmed on sequencing.