Low Genetic Diversity of Hepatitis B Virus Surface Gene amongst Australian Blood Donors.

Ngoc Minh Hien Phan,Wayne J Dimech,Eileen V Roulis,Kirsten M Spann,Robert L Flower,Helen M Faddy

doi:10.3390/v13071275

Abstract

Variants in the small surface gene of hepatitis B virus (HBV), which codes for viral surface antigen (HBsAg), can affect the efficacy of HBsAg screening assays and can be associated with occult HBV infection (OBI). This study aimed to characterise the molecular diversity of the HBV small surface gene from HBV-reactive Australian blood donors. HBV isolates from 16 HBsAg-positive Australian blood donors’ plasma were sequenced and genotyped by phylogenies of viral coding genes and/or whole genomes. An analysis of the genetic diversity of eight HBV small surface genes from our 16 samples was conducted and compared with HBV sequences from NCBI of 164 international (non-Australian) blood donors. Genotypes A–D were identified in our samples. The region of HBV small surface gene that contained the sequence encoding the ‘a’ determinant had a greater genetic diversity than the remaining part of the gene. No escape mutants or OBI-related variants were observed in our samples. Variant call analysis revealed two samples with a nucleotide deletion leading to truncation of polymerase and/or large/middle surface amino acid sequences. Overall, we found that HBV small surface gene sequences from Australian donors demonstrated a lower level of genetic diversity than those from non-Australian donor population included in the study.

Highlights

Hepatitis B virus (HBV) is a leading cause of hepatic disease with an estimated248 million chronic infections and 686,000 deaths per year globally [1,2]
Australian blood donors who resided in Australia and were positive to HIV-1/HCV/HBV
Surface gene nucleotide diversity was lower in our Australian donor HBV

Summary

Introduction

Hepatitis B virus (HBV) is a leading cause of hepatic disease with an estimated248 million chronic infections and 686,000 deaths per year globally [1,2]. Hepatitis B virus (HBV) is a leading cause of hepatic disease with an estimated. The prevalence of HBV infection detected in blood donors varies by country or region, with a prevalence of. 2.3% in China [3], 7.5% in Ghana [4], 2.3% in eastern Mediterranean and middle eastern countries [5] and 0.32% in Italy [6]. In 2016, Australia recorded a low rate of 0.06% HBV infections detected in total first-time blood donations [7]. HBV is a small, enveloped DNA virus with a relaxed circular (rcDNA) and partially double-stranded genome of 3.2 kbp. The HBV genome has four partially overlapping open reading frames (ORFs) coding for the polymerase, pre-surface/surface, pre-core/core and. The pre-surface/surface coding sequences encode large, middle, and small envelope proteins which play an important role in viral attachment to hepatic cells [8]

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