Identification and Characterization of "Candidatus Rickettsia Thierseensis", a Novel Spotted Fever Group Rickettsia Species Detected in Austria.

spp. are the second most common pathogens detected in ticks in Austria after sensu lato. Species belonging to the spotted fever group (SFG) are the causative agents for tick-borne rickettsiosis across the world. So far, only four SFG spp. were detected in Austria, namely , , and . Here, we describe the identification of a new SFG species detected in an tick. Sequencing of various rickettsial genes revealed a nucleotide sequence similarity of 99.6%, 98.5%, 97.3% and 98.5% to the , , , and genes, respectively, of known and validated species. Additionally, sequencing of the gene and 23S-5S intergenic spacer region also only showed 99.6% and 99.2%, respectively, similarity to known species. Therefore, and in accordance with current criteria for species discrimination, we hereby describe a new species of the SFG with putative pathogenic potential. We propose the name " Rickettsia thierseensis" based on the village Thiersee in the Austrian province of Tyrol, where the carrying tick was found.