Prevalence of different Rickettsiaspp. in Ixodes ricinusand Dermacentor reticulatusticks (Acari: Ixodidae) in north-eastern Poland

In two surveys conducted in April and May 2013, a total of 1148 unfed ticks belonging to two species, Ixodes ricinusand Dermacentor reticulatus,were collected by flagging lower vegetation in 15 different localities throughout the Białowieża Primeval Forest (Podlaskie voivodship; north-eastern Poland) and in its buffer zone. In order to establish their infection rate with Rickettsiaspp. individual adult ticks and pooled nymphs were tested by real-time PCR targeting the gltAgene. For the further identification of rickettsial species, positive samples were subjected for nested and semi-nested PCR targeting ompAand 16S rRNA genes, respectively, followed by sequencing analysis. Rickettsial DNA was detected in at least 279 ticks (minimum infection rate [MIR], 23.9%), including 52 nymphal and adult I. ricinus(MIR 8.6%) and 222 adult D. reticulatus(41%). Three species of SFG rickettsiae were identified: Rickettsia helveticaand ‘CandidatusR. mendelii’ in I. ricinusand R. raoultiiin D. reticulatusand I. ricinus.Moreover, unidentified Rickettsiaspp. which showed 99.4% identity, among others, with the uncultured Rickettsiasp. isolated from Cicadella viridisleafhopper, Rickettsiaendosymbiont of Lasioglossum semilucensbee and R. bellii,were detected in I. ricinus,while Rickettsiasp. 98.3-98.4% homologous to Rickettsiasecondary endosymbionts of Curculiospp. weevils was found in D. reticulatus.