Ticks are important vectors transmitting a broad range of pathogens to vertebrates including humans.It is a primary challenge to detect the pathogen profile that a tick population harbours.Here we report deep sequencing of small (s)RNAs extracted from field collected tick Hyalomma rufipes in Gansu Province,China,by using the commercially available Solexa HiSeq2000 technology.The original aim of the experiment was to survey tick and tick:borne viruses that could be subjèct to tick anti:virus RNA interfering (RNAi).In addition to detection of a St.Croix River Virus (SCRV),to our surprise,the sRNA library contained many reads that could be matched to pathogens including bacteria,protozoa and fungi,offering an unexpected opportunity to gain insight into the pathogen community of a tick population.Short sequence de novo assembly was performed to construct a contig library which was used to search against the Genbank to clarify the identities of these sequences.Presence of selected species was validated by using PCR/RT:PCR amplification followed by Sanger sequencing.Further analyses indicated that the virus derived small interfering RNAs (vsiRNA) were mainly the products of tick Dicer RNAsE-Ⅲ that catalysed virus RNAs.The sRNAs of non:viral origin,however,may also included tick PIWI protein products and/or be produced by the pathogen s own RNAi systems.The sRNA deep sequencing approach provides a ready:to:use method for survey pathogen prevalence in vector species.