Genetic variability of HBV strains circulating in the State of Espírito Santo, Brazil: characterization of genotypes/subgenotypes and analysis of mutations in the S and polymerase genes

• Grant number: 16/19850-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2017
• End date: December 31, 2017
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Michele Soares Gomes Gouvêa
• Grantee: Samira Chuffi
• Host Institution: Instituto de Medicina Tropical de São Paulo (IMT). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The World Health Organization estimated that worldwide about 2 billion people have already had contact with the hepatitis B virus (HBV), and 350 million of then are chronically infected. HBV belongs to the Hepadnaviridae family, has typical characteristics of this group as its tropism for liver cells and an unusual replication mechanism through an RNA intermediate. HBV has a large genetic variability, which is also represented by specific mutations with clinical impact, such that in the S gene related with vaccine escape or in the polymerase gene associated with nucleos(t)ide analogue (NA) therapy. The information regarding HBV genetic diversity in Brazil is limited, as well as the prevalence of infections with HBV harboring clinically significant mutations. The Espírito Santo state is one of the Brazilian states that still have regions where endemicity of HBV infection is considered intermediate, and there are no studies on the genetic diversity of HBV strains circulating in the region. Considering the importance of this knowledge to better understand the epidemiology of HBV infection in this state, the aims of this study are to identify the HBV genotypes and subgenotypes involved in cases of chronic infection and the characterization of S and polymerase genes variability to estimate the frequency of infections with strains carrying clinically relevant mutations. (AU)