Novel RNA Viruses Are Harbored By Dermacentor Nuttalli Ticks From Qinghai Province

Ticks are blood-sucking parasites that are important vectors for a variety of zoonotic viral pathogens.From 2015 to 2017,a total of 3162 ticks were collected from farm animals around Qinghai Lake in Qinghai Province,China,which were Dermacentor nuttalli ticks through morphological and molecular examination.Through next generation sequencing(NGS),four novel RNA viruses were found from D.nuttalli ticks.One of them belongs to an unassigned group in genus Phlebovirus of family Phenuiviridae,order Bunyavirales(Qinghai tick-associated phlebovirus,QHTPV)and the others are unclassified.Besides,a number of short fragments belonging to six families were identified.The prevalence of these viruses in ticks was further investigated among tick groups.Furthermore,a putative M segment of QHTPV was found from NGS data,whereas only L and S segments could be found,but M segment was not identified for other members of the group which QHTPV belongs to.It is therefore inferred that this group of Bunyavirus may contain only two segments in their genome.The potential of QHTPV M segment was further characterized by phylogenetic analysis,comparison of genomic organizations and putative post-translational modifications with related phleboviruses,and correlation analysis of QHTPV S,M and L segments among groups.Our study,for the first time,investigated the virome of D.nuttalli ticks in Qinghai Province,which revealed the genetic diversity and promoted the understanding of tick-borne viruses.It was also proved that the newly discovered genome of a Phlebovirus has complete S,M,and L segments,suggesting that the M segment may be difficult to be discovered due to the extremely low sequence similarity.The M segment sequence of the novel Phlebovirus we found will likely facilitate the discovery of other M segment sequences of the new Phlebovirus in the future.