Beware with the backpack! New hosts and pathogens identified for Ixodes simplex ticks collected from bats in the Iberian Peninsula

To improve the knowledge on the role of bats in the maintenance and transmission of tick-borne pathogens, a molecular approach was used to characterize Anaplasma spp., Rickettsia spp., Coxiella burnetii, Borrelia burgdorferi s.l., piroplasmids, Hepatozoon spp., flaviviruses and nairoviruses in ticks collected from Iberian bats. A total of 732 bats from 25 species were captured at 38 sampling sites distributed in seven provinces of Spain between 2018 and 2022. Seventy-nine Ixodes simplex ticks were collected from 31 bats (Eptesicus isabellinus, Hypsugo savii, Myotis capaccini, Myotis emarginatus, Myotis myotis, Miniopterus schreibersii, Pipistrellus pipistrellus and Rhinolophus ferrumequinum). Sixty of 79 I. simplex were positive for at least one pathogen tested and were collected from 23 bats captured in southeast Spain. We detected the presence of Rickettsia slovaca in 12 ticks collected from M. emarginatus, H. savii, M. schreibersii and E. isabellinus; Rickettsia aeschlimannii in 1 tick from M. schreibersii; Anaplasma ovis in 3 ticks from H. savii and M. schreibersii; C. burnetii in 2 ticks from H. savii; Occidentia massiliensis in 1 tick from H. savii; piroplasmids in 12 ticks from H. savii, M. schreibersii and E. isabellinus; and a novel nairovirus in 1 tick from M. schreibersii. Furthermore, blood samples obtained from 14 of the 31 tick-infested bats were negative in all PCR analyses. This study describes new host and pathogen associations for the bat-specialist I. simplex, highlights the risk of spread of these pathogens, and encourages further research to understand the role of Iberian bats in the epidemiology of tick-borne pathogens.