The genetic diversity of Borrelia afzelii is not maintained by the diversity of the rodent hosts.

Background: Small mammals are essential in the enzootic cycle of many tick-borne pathogens (TBP). To understand their contribution to the genetic diversity of Borrelia afzelii , the most prevalent TBP in questing Ixodes ricinus , we compared the genetic variants of B. afzelii at three distinct genetic loci. We chose two plasmid loci, dbpA and ospC , and a chromosomal one, IGS. Results: While the larvae that fed on shrews ( Sorex sp.) tested negative for B. afzelii , those fed on bank voles ( Myodes glareolus ) and wood mice ( Apodemus sylvaticus ) showed high infection prevalences of 0.13 and 0.27, respectively. Despite the high genetic diversity within B. afzelii , there was no difference between wood mice and bank voles in the number and types of B. afzelii haplotypes they transmit. Conclusions: The genetic diversity in B. afzelii cannot be explained by separate enzootic cycles in wood mice and bank voles. [ABSTRACT FROM AUTHOR]