Characterization of the Full-Length Genome Sequences and Phylogenetic Analysis of HDV Strains Isolated from Patients with Chronic HBV and HDV Infection in Kyrgyz Republic

Abstract

Objective. The purpose of our work was molecular genetic characterization of the hepatitis D virus isolates, circulating in the region with high prevalence of HBV + HDV super-infection. Materials and methods. The study material was 64 blood serum samples obtained from Kyrgyz Republic residents - patients with chronic viral hepatitis B+D. The hepatitis D virus complete genomes were sequenced, followed by phylogenetic analysis. Results and discussion. Based on the phylogenetic analysis of 64 HDV samples, it was shown that HDV genotype 1 (96.9 %) predominates in the examined group compared with HDV genotype 2 (3.1 %). Sequences were submitted to GenBank under access No MN984407 through MN984470. When assessing the genetic variability over the examined HDV genotype 1 samples, the maximum genetic distance was 12,49 %, and the minimum – 7,41 %. Within individual clusters, the genetic distance averaged from 2.6 % to 8.5 %. Among the sequences in GenBank, the closest resemblance to the HDV-2 Kyr41 and Kyr43 samples (nucleotide identity was 92.31 % and 89.57 %, respectively) was shown for the virus described earlier in Yakutia (AJ309880). To study the genetic relationships between the analyzed HDV genotype 1 strains in comparison with the HDV reference sequences, the predicted amino acid sequence was studied (111–214). Although hepatitis B preventive measures, including vaccination, have reduced the hepatitis D incidence, there is no effective way to prevent HDV infection in HBV carriers in endemic areas. The HDV sequence molecular-genetic characterization in this study, as well as the viral genomic sequence phylogenetic analysis, will help identify pathogen transmission pathways to control and / or prevent the spread of infection.