Coxiella-like endosymbionts.

In the past two decades, many Coxiella-like bacteria have been found in hard ticks and soft ticks as well as in vertebrate hosts. It is interesting to note that many ticks harbor Coxiella-like bacteria with high prevalence. Coxiella-like bacteria and virulent Coxiella burnetii have high homology to each other; they form a monophyletic clade based on 16S rRNA sequence data and subsequent phylogenetic tree analyses. In this chapter, methods of detection, phylogeny, prevalence and density, distribution in tick organs, transmission routes, bacteria-host interactions, and putative functions of the Coxiella-like bacteria are reviewed.