Coxiella burnetii and Coxiella Endosymbiont in Ticks from Western China.

Background: Coxiella spp. are widespread in ticks. Coxiella burnetii, the agents of Q fever, is vectored by ticks and is well known for its veterinary and medical importance. However, reports on C. burnetii in ticks from China have been quite few compared with other tick-borne pathogens. In addition to C. burnetii, more and more Coxiella endosymbionts of ticks have been described in China. Materials, Methods, and Results: In this study, ticks were collected from domestic animals in two provinces (Chongqing and Xinjiang) in western China, and the Coxiella spp. in them were molecularly studied. In the 168 ticks (all Hyalomma asiaticum) from Xinjiang, C. burnetii was detected with an overall positive rate of 76.19%. In contrast, in 96 ticks (all Rhipicephalus microplus) from Chongqing, only Coxiella endosymbiont was identified with an extremely high prevalence (97.92%). Conclusions: We propose that there may have been a tick-animal-tick circulation of C. burnetii in Xinjiang. The high positive rate of C. burnetii suggests a high risk to public health.