Gagosa Mountain virus, a novel arbovirus identified in Ornithodoros lahorensis ticks from the Shigatse region of the Tibetan Plateau

Ticks are the second most important vectors of human diseases after mosquitoes. Hard ticks are more abundant and widespread than soft ticks, resulting in their greater involvement in diverse diseases. Consequently, most research on tick-borne pathogens has focused on hard ticks. In contrast, soft ticks, which comprise fewer species, have received less research attention. In this study, we identified a novel single-stranded RNA virus (tentatively named Gagosa Mountain virus) in Ornithodoros lahorensis ticks from the Shigatse region of Tibet. We collected 80 engorged soft ticks from Tibetan sheep, placing each in a separate tube for pathogen analysis. Quantitative real-time PCR (qRT-PCR) and nested PCR techniques were employed to confirm the presence of Gagosa Mountain virus, and subsequent analyses focused on elucidating its genomic features and phylogenetic relationships. Our results demonstrated that Gagosa Mountain virus was present in 15 out of 80 ticks, corresponding to a positivity rate of 19%. The 13,133-nucleotide single-stranded negative-sense RNA genome contained six open reading frames (ORFs) encoding the N protein, RdRp, and four hypothetical proteins. Pairwise distance analysis showed high nucleotide sequence identity among the viral sequences. Phylogenetic analysis indicated that Gagosa Mountain virus is most closely related to Lhasa Rhabd tick virus 1, which is an unclassified member of the family Rhabdoviridae. Further analyses demonstrated that Gagosa Mountain virus represents a novel member of the genus Betanemrhavirus within the family Rhabdoviridae.