Detection and Distribution of Tick-Borne Bacterial Pathogens in Ticks from Different Hosts in the Altun Mountains, China

Background: Ticks are the main vectors for a variety of tick-borne bacterial pathogens. Systematic studies on the coinfection patterns and differences of pathogens in ticks derived from different hosts are of great significance. Therefore, the present study investigated ticks collected from multiple host species in the Altun Mountains region (China) to preliminarily characterize differences in the carriage of tick-borne bacterial pathogens across host-associated and environmental tick populations and to explore their potential relationships. Materials and Methods: A total of 2820 ticks collected from marmots, sheep, camels, and Gobi vegetation were assigned into 562 pooled groups. Polymerase chain reaction assays were performed to detect multiple tick-borne bacterial pathogens, followed by phylogenetic analysis of representative sequences. Results: Ticks in the Altun Mountains region carried multiple tick-borne bacterial pathogens with distinct host-associated distribution patterns. Moreover, there were significant differences in the pathogen carriage profiles among ticks from different hosts and environmental sources. In particular, the distributions of spotted fever group (SFG)/typhus group (TG) rickettsiae, Anaplasma spp ., and Coxiella burnetii in ticks from different hosts were significantly different ( p < 0.05). SFG/TG rickettsiae were the dominant pathogens forming highly conserved phylogenetic clusters and widely distributed in ticks. Furthermore, Anaplasma spp. were distributed across multiple phylogenetic clades. Conclusion: These findings indicate that tick-borne pathogens in the Altun Mountains region exhibit distinct host-associated distribution characteristics and complex ecological circulation characteristics.