Molecular Identification of Borreliella Species in Ixodes hexagonus Ticks Infesting Hedgehogs (Erinaceus europaeus and E. roumanicus) in North-Western Poland

The western European hedgehog (<i>Erinaceus europaeus</i>) and the northern white-breasted hedgehog (<i>E. roumanicus</i>) are natural hosts of the tick <i>Ixodes hexagonus</i>, the vector of tick-borne pathogens such as the <i>Borreliella</i> bacteria responsible for Lyme disease. The aim of this study was to identify these pathogens in ticks collected from hedgehogs in northwestern Poland and to assess their genetic diversity by molecular analysis of the detected pathogens based on the <i>flaB</i> gene and the <i>mag-trnI</i> intergenic spacer. Among 101 hedgehogs examined, 737 ticks were found on 56 (55.45%) individuals, including 501 females of <i>I. hexagonus</i>. <i>Borreliella</i> spirochete infection was confirmed in 9 females of <i>I. hexagonus</i> (1.8%) obtained from 4 (3.96%) hedgehogs, detecting <i>Borreliella (Bl.) afzelii</i> (8/89%) and <i>Bl. spielmanii</i> (1/11%). Phylogenetic analysis based on the <i>flaB</i> gene and the <i>mag-trnI</i> intergenic spacer showed a lack of diversity in <i>Bl. afzelii</i> detected in <i>I. hexagonus</i> ticks collected from hedgehogs as well as little diversity against reference strains detected in small mammals and ticks collected from them. The results confirm that hedgehogs play an important role in the circulation of the detected spirochete species, at least as hosts of <i>I. hexagonus</i> ticks infected with them, indicating their potential to spread <i>Borreliella</i> spirochetes.