Molecular epidemiology of hepatitis B and C virus infections in Asia

Abstract

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.

New Complex Recombinant Genotype of Hepatitis B Virus Identified in Vietnam

“…To date, intergenotype recombination with genotype B/C (15,25) was surprising, because the circulating HBV genotypes in Vietnam are B, C, and rarely A (27,28). More interestingly, genotype G is quite rare in Asia and undetectable in Vietnam (6,28). With the limited data available, the mechanism of this complex intergenotype is still unclear, although there is a report of HBV (DQ078791) with the C/G recombinant genotype in Thailand (26).…”

“…Eight HBV genotypes from A to H are defined by a divergence in the entire nucleotide sequence of more than 8% (1,14,18,19,23). The prevalence and distribution of HBV genotypes vary geographically (6,8,9). Some genotypes have been split into subgroups.…”

An Overview of Hepatitis B Virus Surface Antigen Mutant in the Asia Pacific

“…In Asia, genotype A can be found at a high frequency in India, Indonesia and the Philippines (Weinberger et al, 2000). Genotypes B and C are found mainly in the Far East, such as in China, Japan and the South-East Asia region (Huy and Abe, 2004), genotype I is found in Vietnam, Laos, North western China and isolated valleys of northern India, while the 10 th genotype, J, has been reported in a Japanese patient (Tatematsu et al, 2009). Therefore, in the Asia Pacific region, four genotypes (B, C, I and J) largely dominate.…”

Hepatitis B virus infection contributes to oxidative stress in a population exposed to aflatoxin B1 and high-risk for hepatocellular carcinoma

“…HBV-induced chronic active hepatitis and cirrhosis constitute major risk factors in liver carcinogenesis [3]. HBV is associated with 70∼75% of all HCC cases in Asia, the continent with the highest prevalence of HBV [4]. Also, the role of dietary exposure to aflatoxin B1 (AFB1), a category I known human carcinogen and a potent genotoxic agent, in the development of HCC has long been documented in many model systems (reviewed in [5][6][7]).…”