Presence of CandidatusNeoehrlichia mikurensis and Babesia microtiin rodents and two tick species (Ixodes ricinusand Ixodes trianguliceps) in Slovakia

Rodents are important reservoir hosts of many tick-borne pathogens. Their importance in the circulation of the emerging bacterial agent, CandidatusNeoehrlichia mikurensis and the intraerythrocytic protozoan parasite, Babesia microtihas been recently proposed. The aim of the present study was to identify the presence and genetic diversity of CandidatusN. mikurensis and B. microticirculating in the natural foci among rodents and two species of ixodid ticks (Ixodes ricinusand Ixodes trianguliceps). In 2011–2013, rodents were captured at sampling sites in Eastern Slovakia. A total of 997 rodents (324 Apodemus agrarius, 350 Apodemus flavicollis, 271 Myodes glareolus, and 52 other rodent species), 788 feeding ticks from rodents, and 1375 questing ticks were investigated for the presence of pathogens by molecular methods followed by DNA sequencing. CandidatusN. mikurensis was detected in 2.4% of questing I. ricinusnymphs and 2.6% of questing adult I. ricinusticks, spleens of rodents (1.6%), as well as in feeding larval I. ricinus(0.3%) and feeding larval I. triangulicepsticks (3.3%). The 16S rRNA and gltA gene sequences of CandidatusN. mikurensis obtained in this study confirmed a high degree of genetic identity of this bacterium in Europe. DNA of B. microtiwas found in ear (0.6%) and spleen biopsies of rodents (1.9%), in rodent foetus (3.8%) and feeding larval (5.2%) and nymphal (8.7%) I. ricinus, in questing nymphal I. ricinus(0.5%) and questing adult I. ricinusticks (0.3%). None of the 112 I. triangulicepsticks were infected. B. microtiwas represented by two different genotypes: 92% of the positive samples belonged to the zoonotic type strain from Jena (Germany). The results of this study underline the importance of rodents in the circulation of both emerging pathogens in natural foci.