PHYLOGENETIC ANALYSIS OF TWELVE BULGARIAN SEQUENCES BASED ON PARTIAL OPEN READING FRAME 2 GENOME FRAGMENT OF HEPATITIS E VIRUS

Background: Hepatitis E virus (HEV) causes both acute and chronic liver inflammation. HEV is transmitted through the fecal-oral mechanism and infects both animals and humans. The virus belongs to the Hepeviridae family and its genome is a single stranded RNA molecule. Thanks to molecular sequencing methods different genotypes and subgenotypes have been established. The aim of the present study was to identify and characterize Bulgarian HEV sequences by applying Sanger sequencing technique for a genome fragment in Open Reading Frame 2 (ORF2 region). Material and methods: Twelve retrospective samples from patients with serologically confirmed HEV infection (anti-HEV IgM and IgG positive) were sequenced by Sanger sequencing. Sequencing data were analysed by BioEdit, MEGA11 and NCBI Genbank software tools. Results: The results revealed that all isolates assign to species Paslahepevirus balayani. Phylogenetic analysis showed that HEV isolates were characterized with considerable genetic diversity. The sequences were sub-clustered into the following subgenotypes: HEV-3e, 3m, 3f and 3c. Conclusion: We successfully applied the Sanger method for hepatitis E virus RNA sequencing. The established heterogeneity of subgenotypes requires further study in order to determine the circulation of all possible subgenotypes of HEV in the country.