| Object:Ticks are exoparasites that specialize in blood sucking.Besides biting and attacking the host directly,they are also vectors of many kinds of natural epidemic pathogens.Ticks research is of great significance in veterinary medicine,medicine,economics and public health.The Junggar basin is the second largest inland basin in China.It is located in the north of Xinjiang.The vegetation coverage is good,most of which are excellent pastures.There are many wild animal populations,which provide good habitat for ticks breeding.To investigate tick species and tick-borne pathogens in northern Xinjiang,improve the basic data of tick species and tick-borne pathogens in this area,and provide reference for the analysis of tick population distribution and the prevention and control of tick-borne diseases in this area.Methods:(1)Ticks were collected from 16 sites in 15 counties of northern Xinjiang from 2014 to 2016 years,and the distribution characteristics and dominant species of ticks were determined by morphological identification.(2)The 16 S rDNA genes of different ticks were amplified to confirm the results of morphological identification.The phylogenetic relationship of ticks in this area was determined by comparing 16 S rDNA gene sequences and constructing phylogenetic tree.(3)The genetic relationship and classification status of Hyalomma asiaticum asiaticum and Hyalomma asiaticum kozlovi were discussed through the determination,annotation,comparison and analysis of mitochondrial genome.(4)The nucleic acid of human granulocyte intangibles,Erickettsia and Lyme spirochetes were detected by nested PCR to understand the positive rate of pathogens carried by ticks in different regions and species.The amplification and sequence analysis of 16 S rDNA gene of human granulocyte intangibles and Ericketia mitochondria and 5S-23 S rRNA gene spacer of Lyme disease spirochetes were carried out.To determine the genotype and phylogenetic relationship of the pathogen.(5)Trypanosoma evansi was isolated and cultured from the naturally occurring camel and the surface-parasitic Hyalomma asiaticum asiaticum.The 18 S rDNA and ITS1-5.8S-ITS2 genes of Trypanosoma evansi were detected by PCR.The isolated strains were identified and the transmission of Trypanosoma evansi by Hyalomma asiaticum asiaticum was discussed.Results:(1)From 2014 to 2016,11628 ticks were collected from 16 sampling sites in 15 counties around Gurbantunggut Desert in northern Xinjiang,belonging to 5 genera and 10 species.Those were obtained Hyalomma asiaticum asiaticum,Hyalomma asiaticum kozlovi,Hyalomma detritum.,Dermacentor nuttalli,Dermacentor silvarum,Dermacentor niveus,Dermacentor marginatus,Rhipicephalus turanicus,Haemaphysalis punctate and Ixodex persulcatus.The intermedius type of Hyalomma asiaticum asiaticum and Hyalomma asiaticum kozlovi were detected.(2)Ixodes were collected from 16 sampling sites in 15 counties and municipalities around Gurbantungut Desert in northern Xinjiang.The 16 S rDNA gene was amplified and 16 tick sequences were obtained,which belonged to Hyalomma,Rhipicepphalus,Dermacentor and Haemaphysalis.The results were consistent with the morphological identification.A phylogenetic tree was constructed based on 16 S rDNA gene,which improved the basic data of phylogenetic and taxonomic data of Ixodes in northern Xinjiang.(3)The complete mitochondrial gene sequences of H.asiaticum asiaticum and H.asiaticum kozlovi were successfully obtained,with lengths of 14720 bp and 14724 bp,respectively.The complete mitochondrial gene sequences were annotated and analyzed.The similarity rate of the two tick species was 99.65%.The genome composition and sequencing are consistent.It is considered that H.asiaticum asiaticum and H.asiaticum kozlovi are the same species and should be synonymous.(4)500 ticks collected from 15 counties and municipalities in northern Xinjiang were tested for nucleic acid of Erikosome,human granulocyte intangibles and B.burgdorferi sensu stricto.The total positive rate of Erikosome and human granulocyte intangibles was 25.24% and 31.2% respectively.The total positive rate of B.burgdorferi sensu stricto was 3.2%.(5)A Trypanosoma was isolated from the ticks of the camel and the parasitic Hyalomma asiaticum asiaticum on the surface of the white beetles.It is confirmed that H.asiaticum asiaticum is one of the transmission vectors of Trypanosoma evansi combined with molecular biology analysis.Conclusion: 11628 ticks were collected,belonging to 5 genera and 10 species.The morphological identification is basically consistent with the literature records H.asiaticum asiaticum,H.asiaticum kozlovi,D.niveus and D.nuttalli are the dominant ticks.Based on the identification of 16 S rDNA gene of Ixodes,the results were consistent with those of morphological identification.Mitochondrial genome sequencing analysis showed that H.asiaticum asiaticum and H.asiaticum kozlovi were homologous;Erichia,human granulocyte intangible body and Lyme spirochete were detected in Ixodes in northern Xinjiang,suggesting that this area was a homologous synonym.The natural foci of this pathogen;the isolation of Trypanosoma evansi Karamay strain confirmed that Hyalomma asiaticum asiaticum was one of the transmission vectors of Trypanosoma evansi. |
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