OP-2 ANALYSIS OF THE GENETIC DIVERSITY OF HEPATITIS DELTA VIRUS CIRCULATING IN BRAZIL BETWEEN 2013 AND 2021 AND ITS RELATIONSHIP WITH HEPATITIS B VIRUS

Introduction and Objectives

Hepatitis D virus (HDV) is a defective virus dependent on the hepatitis B virus (HBV) to replicate. Currently, HDV is divided into 8 genotypes and several subgenotypes, HDV-1 and 3 being predominant in Brazil. Although crucial to understanding the evolution and spread of the virus worldwide, few studies address the genetic variability of the complete HDV genome. This study aimed to investigate the genetic variability of HDV in Brazil.

Materials and Methods

From 41 anti-HDV positive sera collected between 2013 and 2021 in distinct Brazilian regions, 12 HDV genomes were obtained by RT-PCR. Additionally, a fragment of ∼900 base of S/POL regions of HBV genome was PCR amplified. The amplicons were sequenced using the Sanger method and phylogenetically analyzed.

Results

The phylogeny showed the circulation of HDV-3 (10/12; 83,3%), HDV-5 (1/12; 8,3%) and HDV-8 (1/12; 8,3%). Most HDV-3 samples (8/10; 80%) were found in the endemic North Brazilian region, while two were found in Brazilian non-endemic areas. HDV-5 and 8, whose circulation is usually restricted to African countries, were found in São Paulo, a cosmopolitan city from Southeast Brazil. Phylogenetic analysis of HDV-8 strains indicated that the sample in our study, along with previously reported sequences from Brazil, formed a highly supported monophyletic clade, probably representing a new HDV-8 subgenotype. Among HBV sequences, the association between HDV/HBV genotypes was: HDV-3/HBV-F2 (5/11; 41.7%), HDV-3/HBV-A1 (2/11; 18.2%), HDV-3/HBV-D3 (1/11; 9.1%), HDV-3/HBV-D4 (1/11; 9.1%), HDV-5/HBV-E (1/11; 9.1%) and HDV-8/HBV-E (1/11; 9.1%). The HBV genotypes commonly found in Brazil, HBV-A, HBV-D and HBV-F, were detected in coinfection with HDV-3, endemic in the country. However, HBV-E, native from Africa, was found in coinfection with HDV-5 and HDV-8, suggesting allochthonous infection.

Conclusions

This study emphasizes the importance of epidemiological surveillance in mapping HDV transmission pathways and imported variants.