Generally, wild-animals serve as a huge and often unknown reservoir hosts for zoonotic disease, included tick-borne infections . Many wild-animals, such as lizards, wild boars, hedgehogs, and snakes have been identified as hosts of ticks [34, 35, 36]. In reality, the study of ticks in lizards is rare, especially in China. Statistically, only 6 tick species have been reported collected from lizards in China: A. javanense、A. cordiferum、A. varanense、A.crassupes、I. nipponensis and H. sulcata . Hence, we know little about lizard-ticks. Over the past ten years, our team had obtained more than ten thousand lizards (including 6 genus, 17 species), whereas only few of them were detected tick infesting. Consequently, ticks parasitic on lizards has been identified for the first time in arid desert regions of Xinjiang in China based on molecular technique.
Consistent with the traditional taxonomy, 31 ticks from E. multiocellata-lizard of 4 sampling sites in this study belonged to 3 genera and 3 species (H.sulcata, Hy. asiaticum and R.turanicus). Similarly, 47 ticks from hedgehog and 1 from brushwood for reference also belonged to the 3 genera and 3 species. In previous studies, most of reptile-ticks are distributed in southern regions in China, which have a similar ecological environment . However, In northern regions China-Xinjiang, only a particularly species H.sulcata was reported that feed on reptiles. In this study, the H. sulcata haplotypes obtained from lizards, which based on the three genetic locus, were clustered together with the H. sulcata sequences derived from Genbank. Meanwhile the MJ network (Fig. 6) showed that H. sulcata have shorter distance to these haplotypes than others. In this case, we can conservatively infer that 17 ticks collected from lizard has been identified to the species H. sulcata.
Interestingly, in this study, we not only found H. sulcate feed on lizards, but also found two local dominant species, Hy. asiaticum and R.turanicus, in Xinjiang. A previous survey of ticks from livestock also reported that H.sulcata、Hy.amasiticum and R.turanicum were found in Tarim Basin, Xinjiang. As the MJ network based on COI haplotype of Hy. asiaticum showed that Z7 shared the same haplotype with 2 ticks from Gansu and 3 from Kazakhstan (Fig. 8). The reason could be their geographical origins that Gansu and Kazakhstan border upon Xinjiang. In the meantime, there still have private lizard-tick haplotype (Z10 and Z11) in Xinjiang. In agreement with the previous surveys [8, 37], our work showed that Hy. asiaticum was the prevalent species in Xinjiang, with more than 63% of ticks in the present study. In the previous study, R. turanicus was widely distributed species in the desert and semi-desert areas in the Southern region of Xinjiang [38, 39]. However, the abundance of this species seems to reduce partly due to the limit of sample size in the present study. In order to extend knowledge of tick species infesting lizards and their potential to cause tick-borne diseases, more investigations are needed. This may suggest that the reason why reptile-ticks are thought to be less distributed in northern China, perhaps because of a lack of research on ticks-reptiles.
Actually, thousands of lizards were captured during 2015 to 2019 in summer by our lab, which belong to the genera Eremias and Phrynocephalus from different sampling sites of the arid desert regions covered 68 counties of Xinjiang [40, 41] No tick was found on the lizards of other species belong to the genus Eremias and the species of Phrynocephalus, and no tick was found on the E. multiocellata-lizard from other sampling sites except for the 4 sites (P3, P4, P5 and P6), on the north of the Tarim basin. There are several factors may affect the distribution of tick species, such as the climate、Human land-use patterns、geographical habitats and hosts. The Tarim Basin, an endorheic basin in southern Xinjiang, located between Kunlun Mountais, Tianshan and Altun Mountains. Various landscapes of the Tarim Basin composed of desertification grassland、a salinized desert and an human and animals inhabit oases . In conclusion, we suggest that the characteristics found in this study of ticks in Xinjiang is closely related to the geographical environment.
The ticks collected from E. multiocellata-lizard were in small size ranged from 1 to 2 mm in width and were immature. This phenomenon was also found in the investigation of ticks and tick-borne pathogens in the Northern Apennines that total 68 lizards were infested by immature ticks. . The explanation of this phenomenon may be speculated that the immature period of most ticks was classical live in nest-dwelling parasitism [4, 43]. Lizards live in caves, even some holes extremely small. It seems that lizards should to be a suitable host for ticks which are in immature period. On the other hand, we should enlarge the sample size in future research to exclude the possibility that tick morphometric characteristics on hosts are a random sample .
Multiple animals are well-known vectors of ticks in the spreading mechanism of tick-borne pathogenic microorganisms. It was reported that Rickettsia raoultii has been collected from H. erinacei parasiting marbled polecats . Likewise, in China, the Theileria ovis have been identified in R. turanicus that collected from sheep . Previously, in our team, Zhang et al.  had identified that lizards harbored Leishmania parasites. Therefore, we could reasonable speculate whether ticks play a role in the transmission of Leishmania . Tick-borne pathogens have particular relationships with their reservoir hosts . Xinjiang, adjacent to 8 countries (Russia, Kazakhstan, Kyrgyzstan, Tajikistan, Pakistan, Mongolia, India and Afghanistan), is an important transportation hub. The economic system of Xinjiang is mainly agriculture and animal husbandry, thus farmers and herdsmen are in close contact with livestock, reptiles and ticks. Therefore, the spread and epidemic risk of ticks-borne disease in this area is grim, the ability of early warning, prevention and control of tick-borne diseases should be improved. Further studies on storage and transmission of pathogens in ticks are needed to help us control ticks and tick-borne diseases efficiently.