Molecular Detection of Coxiella-like Endosymbionts in Ticks in Hebei, China

Ticks are widely distributed in China and can carry and transmit a variety of pathogens that potential to cause serious impacts on public health and the economy. Little is known about the broader spectrum of Coxiella-like endosymbiont (CLE) in ticks under natural conditions in China. The aim of this study was to detect, analyze, and characterize phylogenetically CLE found in ticks in Hebei Province, China. A total of 947 ticks collected from Hebei Province were identified as Haemaphysalis longicornis based on morphological characteristics and cytochrome c oxidase gene PCR analysis of extracted DNA. Subsequently, DNA was analyzed via PCR for the IS1111 gene (frequently associated with Coxiella burnetii), and the amplified DNA was then sequenced and analyzed phylogenetically using a set of primers targeting the 16S rRNA, groEL, and rpoB genes. A total of 8.24% (78/947) of ticks from the Chengde, Baoding, and Cangzhou regions were positive in the IS1111 PCR. Phylogenetic analysis using the 16S rRNA, groEL, and rpoB genes revealed the presence of CLE in Ha. longicornis ticks from these regions and the formation of two distinct clades, suggesting horizontal gene transfer events. Our results strengthen the growing evidence that CLE, not Coxiella burnetii, is ubiquitously associated with ticks across diverse geographic locations—a distinction critical for accurately interpreting tick microbiome surveys and avoiding false assumptions of zoonotic risk.