Detection of Circulating HBV QSA3/E Recombinants and HDV Genotype GT5 amongst blood donors in Senegal

BackgroundSenegal has a high burden of hepatitis B virus (HBV); however, HBV molecular epidemiology is sparse, and coinfection with hepatitis delta virus (HDV) is poorly investigated.A blood donor panel was evaluated to characterize circulating HBV genotypes, HDV prevalence, and assess the performance of ultrasensitive HBsAg Next, HBV DNA, anti-HDV Total Ig, and HDV RNA diagnostic assays. MethodsPre-screened, non-transfused specimens (n=320) were tested for HBV and HDV biomarkers on the Alinity i platform.Comparator HBsAg testing was assessed with Elecsys HBsAg II.Specimens reactive for HBsAg and/or anti-HDV were tested for HBV DNA and HDV RNA.Specimens with sufficient viral load underwent next-generation sequencing.Phylogenetic inference was assessed with maximum likelihood trees and recombination analysis conducted on basal sequences. ResultsTesting revealed reactive results for HBsAg (87.2%), anti-HBc (92.8%), anti-HBs (6.9%), HBeAg (3.8%), and anti-HDV (1.3%).HBsAg Next Qualitative and Elecsys HBsAg II concordance was 311/319 (97.5%), with n=8 (2.5%) samples not detected by Elecsys HBsAg II.Confirmatory testing verified HBsAg positivity for the 8 discordant specimens.Sequencing (n=104) resulted in >70% genome coverage for n=74 specimens and phylogenetic analysis identified HBV Quasisubgenotype A3 (QSA3) (40.5%),A basal (1.4%), D (5.4%), E (52.7%), and 2 HDV GT5 genomes.Recombination analysis revealed two HBV QSA/E 3 recombinants. ConclusionThis study provides, to our knowledge, the first HBV sequences from Senegal in 20 years and highlights a predominance of genotypes E, QSA3, and notably two unique QSA3/E recombinants.The improved detection of HBsAg Next Qualitative on samples with low levels of HBsAg highlights the importance of ultrasensitive assays.