Abstract:

[Objective] The present study was conducted to understand the species and molecular genetic characteristics of ticks on body surface and in habitat of Tarim red deer （Cervus canadensis）. [Method] A total of 69 ticks were collected from body surface and habitat of Tarim red deer in a large scale farm in Yuli County of Xinjiang, China. Morphological observation and preliminary species identification were performed by stereomicroscope. PCR assays targeting on mitochondrial SSU rRNA gene and COX I gene were performed. The species of the obtained ticks was identified by sequence alignment of the two genes, and their molecular characteristics were analyzed by bioinformatics method. [Result] Morphological observation showed that all of the 69 ticks, including 37 females and 32 males, were identified as belonging to the genus Hyalomma. The SSU rRNA gene sequence of 63 ticks was successfully obtained. Based on the sequence alignment of SSU rRNA gene, 18 ticks were identified as Hyalomma detritum （H. detritum）, and all of them were the same sequence type designated as SCtype1 （n=18）; 45 ticks were identified as Hyalomma asiaticum （H. asiaticum） with 4 sequence types designated as SYtype1 （n=3）, SYtype2 （n=40）, SYtype3 （n=1） and SYtype4 （n=1）, respectively. The COX I gene sequence of 64 ticks was successfully obtained. Based on the sequence alignment of COX I gene, 24 ticks were identified as H. detritum with 2 sequence types designated as CCtype1 （n=22） and CCtype2 （n=2）, respectively; 40 ticks were identified as H. asiaticum with 5 sequence types designated as CYtype1 （n=25）, CYtype2 （n=7）, CYtype3 （n=4）, CYtype4 （n=3） and CYtype5 （n=1）, respectively. Phylogenetic analysis showed that at SSU rRNA gene, the sequences of H. asiaticum formed an individual subgroup branch, and formed a large subgroup branch with those of other Hyalomma species; at COX I gene, the sequences of H. detritum and H. asiaticum formed an individual subgroup branch, while belonged to different subgroup branches with those of other genus in the family Ixodoidea. [Conclusion] The species of the ticks collected from body surface and habitat of Tarim red deer in Yuli County are H. asiaticum and H. detritum. Our results provide basic data for species distribution investigation and genetic evolution characterization of parasitic ticks in Cervidae animals.

Key words: ticks, morphology, sequence, identification, Tarim red deer