Comparative analysis of whole-genome sequences of African swine fever virus (Asfarviridae: Asfivirus) isolates сollected on the territory of the left bank of the Dnieper River in 2023.

Abstract

Introduction: The lack of data on the whole-genome sequences of African swine fever virus (ASFV) variants circulating on the territory of the left bank of the Dnieper River complicates the understanding of the molecular evolution of the virus and the character of the epidemic process development in Russia and Ukraine. Understanding the genetic divergence and phylogenetic relatedness of isolates can largely adjust the strategy of general and specific prevention of the disease. The aim of the study - search and description of unique mutations (deletions/insertions/substitutions) in isolates collected from domestic pigs in Donetsk, Luhansk and Zaporozhye regions in 2023; determination of relatedness and level of homology with reference strains of ASFV genotype II; sub-genotyping and clustering of isolates based on whole-genome analysis.

Materials and methods: The samples used were a culture suspension of porcine bone marrow (PBM) cells containing ASFV isolates obtained from pathologic material from domestic pig carcasses. Genomic DNA was prepared by purification and concentration of virus followed by phenol-chloroform extraction of total nucleic acid. The high-throughput sequencing process was performed using MGI technology. Consensus sequences were assembled by mapping reads to the reference genome of strain Georgia 2007/1.

Results: All isolates are assigned to genotype II, have a monophyletic origin, are phylogenetically close to the clusters «Europe» (4/5) and «Bryansk 2021» (1/5), and are divergent from the original parental genetic variants that make up the enlarged clades. In addition, numerous substitutions in the loci of the multigene family MGF 110, 505, and 360, encoding virulence proteins, were detected in 4 isolates from Donetsk and Zaporozhye regions.

Conclusion: The phylogeny of the genotype II ASFV, which originated from the reference strain Georgia 2007/1, is shown to be sufficient for isolate differentiation. The presented data are of theoretical and practical importance for domestic and international ASFV surveillance.