Identification of spp. in Ticks Removed from Tick-Bitten Humans in Northwestern Spain.

Tick-borne rickettsioses (TBRs) are distributed worldwide and are recognized as important emerging vector-borne zoonotic diseases in Europe. The aim of this study was to identify tick-associated among ticks removed from humans, and to track how tick populations and their associated pathogens have changed over the years. For this purpose, we conducted a tick surveillance study in northwestern Spain between 2018 and 2022. Ticks were morphologically identified and analyzed for the presence of rickettsial pathogens through the amplification of the citrate synthase () and the outer membrane protein A () genes. PCR products were sequenced and subjected to phylogenetic analyses. We collected 7397 ticks, with being the species most frequently isolated. Based on the PCR results, DNA was detected in 1177 (15.91%) ticks, and 10 members of were identified: , subsp. , subsp. , , , subsp. , , , R. barbariae, and R. rioja. Some of these have gone previously undetected in the study region. There is clear geographic and seasonal expansion not only of tick populations, but also of the associated . The comparison of our data with those obtained years ago provides a clear idea of how the spatiotemporal distributions of ticks and their associated Rickettsiae have changed over the years.