The Study On The Diversity Of Virus In The Serum Of Thoroughbred Horse In Northern Xinjiang

Objective:In order to clarify the background data of imported thoroughbred horses carrying viruses in northern Xinjiang area and the epidemiological characteristics of the viruses carried in thoroughbred horses of different origins,to provide data basis for avoiding biosafety risks brought by introduction.Method:(1)Collect the serum of thoroughbred horse in northern Xinjiang area,extract the virus nucleic acid in the mixed sample,reverse transcribe it into cDNA,add anchor primer,synthesize DSC DNA,amplify it by PCR,detect the product by electrophoresis,send the qualified sample to Shanghai paisenno company for high-throughput sequencing,and find out the virus background data of thoroughbred horse.(2)The pathogen was locked according to the virome results,and the new thoroughbred horse virus was mined by PCR method to obtain complete virus species data information.Some gene sequences or whole genome sequences of the virus were determined,and genotyped to study the genetic derivation relationship between strains from different sources.(3)The virus positive rate of feces,serum and nasal swab samples collected were tested to determine their prevalence in horses.Result:(1)In this study,a total of 224 thoroughbred horse serum samples were collected and analyzed for viral metagenomics.A total of 8 virus genera were found and 69 607 706 sequencing reads were obtained.3.16%of mammalian viruses include the Picobirnaviridae Paramyxoviridae,Retroviridae,Genomoviridae,Smacoviridae,Parvoviridae,Circoviridae,Papillomavirus.(2)The results of identification of 5 viruses showed that the positive rate of HPV18 type in thoroughbred horses was 20%,and that of YiLi horses was 12.7%;the HPV18 E6 gene had 94.6%to 97.3%nucleotide homology with human-derived reference sequences,and was similar to horse-derived EcPVs.E6 gene nucleotide homology is 35.8%～40.1%.The complete gene sequence of EcPV1 type was amplified.EcPV1 with other EcPV1～9 whole genome sequence nucleotide homology reached 99.3%～99.4%.This indicates that horse-derived human papillomavirus may be a foreign virus carried by thoroughbred horses.The F gene homology between horse-derived PIV5 and human-derived PIV5 AGS strains detected in feces is as high as 99.8%～100%,and the F gene sequences of the three horse-derived PIV5 strains were obtained;the virus-positive rate of EqPV-CSF was 25.3%.No positive results were detected in Ili horses raised in the same field as thoroughbred horses with positive EqPV-CSF test.Horse Kirko virus Cj-7-7 was identified in a feces of dead thoroughbred horses and the full sequence was amplified.Testing of Yili horses and Przewalski horses showed positive carrier,indicating that Kirko virus was present in Chinese horses.This is also the first time that EqPV-CSF and Kirko viruses have been found in Chinese herds.The genomic sequences obtained in this study have been submitted to GenBank.Conclusion:In this study,a comprehensive survey of the thoroughbred horse serovirus group in Xinjiang was conducted by high-throughput sequencing technology.8 virus genera were found and 5 new viruses were verified,and their positive rates were screened.In this study,viral metagenomics of thoroughbred horses in Xinjiang was studied.The discovery of these viruses enriched the viromics data of thoroughbred horses in Xinjiang,which reflected the efficiency of viral metagenomics analysis in mining viral information and played an important guiding role in avoiding introductions.