The complete nucleoprotein gene molecular characterization of Akabane Virus in Türkiye

Akabane virus (AKAV), a member of the Peribunyaviridae family, is an important arbovirus causing reproductive disorders and congenital abnormalities in ruminants. This study aimed to molecularly characterize AKAV isolates from different regions of Türkiye and assess their phylogenetic relationships using complete N gene sequences. A total of seven AKAV-positive samples, obtained from sheep fetuses and one Culicoides imicola specimen, were analyzed. Viral RNA was extracted, and the full-length N gene (702 nucleotides) was amplified and sequenced. Sequence analysis showed 519 conserved nucleotide sites and 183 conserved amino acid residues. Among genogroup Ib isolates, nucleotide similarity ranged from 95.72% to 100%, and amino acid similarity from 98.29% to 100%. A total of 47 nucleotide and 6 amino acid substitutions were identified; however, none were located within predicted epitope regions. Seven potential B-cell epitopes in the N protein were predicted and found to be conserved across all isolates. Phylogenetic analysis revealed that all Turkish isolates clustered within genogroup Ib and formed a distinct clade with Israeli isolates from 2018, while older Israeli and Japanese strains grouped separately within the same genogroup. Overall, AKAV strains circulating in Türkiye show high genetic similarity and conserved antigenic regions, contributing to a better understanding of the virus's molecular epidemiology.