Landscape and ecological correlates of tick-associated viruses in Inner Mongolia, China

Ticks harbour complex RNA viromes containing both confirmed pathogens and numerous viruses with unknown transmission routes. Defining the diversity and ecological correlates of these viral communities is critical for assessing potential risks to human and animal health.

This study aimed to characterise the diversity, geographic structure, and ecological determinants of RNA viromes in six dominant tick species across Inner Mongolia, China.

We performed meta-transcriptomic sequencing on Ixodes persulcatus, Dermacentor nuttalli, Dermacentor sinicus, Hyalomma scupense, Hyalomma marginatum, and Hyalomma asiaticum. Phylogenetic relationships, viral host specificity, and the influence of environmental factors on virome composition were analysed.

This study identified 146 RNA viral sequences representing 36 viral species, including seven putative novel RNA viruses. The virome also contained several known tick-borne viruses (TBVs), including Alongshan virus (ALSV), tick-borne encephalitis virus (TBEV), and Beiji nairovirus (BJNV). These pathogens showed high genetic diversity and recombination signals in eastern Inner Mongolia. Phylogenetic analyses indicated close clustering with strains from northeastern China and Russia. While 15 viruses were shared among multiple tick species, 13 were host-specific. I. persulcatus and H. asiaticum exhibited significantly higher virome richness and diversity compared to other species. Statistical analysis revealed that virome diversity was significantly associated with both tick species identity and environmental factors, including enhanced vegetation index (EVI) and annual mean wind speed (WIN).

This study delineates the spatial structure of tick-associated RNA viruses in Inner Mongolia, highlighting that tick species identity and environmental conditions jointly shape virome diversity. These findings provide an ecological context for tick-virus associations and a foundation for future research on the transmission and pathogenic potential of emerging tick-borne viruses.