Red foxes (Vulpes vulpes) are exposed to high diversity of Borrelia burgdorferi sensu lato species infecting fox-derived Ixodes ticks in west-central Poland

Abstract Background: The red fox, Vulpes vulpes is the most widely distributed terrestrial carnivore species in Europe, which is parasitized by exophilic as well as nidicolous Ixodes ticks. However, the role of these canids and their tick fauna in the maintenance of Borrelia burgdorferi sensu lato (s.l.) is still insufficiently understood. Results: A total of 1,583 ticks were removed from ears of 120 infested animals and were identified to species using a nested PCR targeting the ITS2 and cox1 fragments of Ixodes DNA. Ixodes kaiseri prevailed (76%), followed by I. canisuga (12%), I. ricinus (10%), and I. hexagonus (2%). In total, 32.4% of 943 ticks yielded Borrelia DNA and ten species of B. burgdorferi s.l. complex were identified. Borrelia garinii and B. afzelii composed 70% of all infections. The other eight species included B. americana, B. bissettiae, B. burgdorferi sensu stricto (s.s.), B. californiensis, B. carolinensis, B. lanei, B. spielmanii, and B. valaisiana. Analysis of 229 foxes showed that 25% were infected with B. burgdorferi s.l. Borrelia garinii was detected in 91% of the infected animals, including 31% of mixed infections with B. afzelii, the second most prevalent species, followed by B. spielmanii. Conclusions: The clear predominance of B. garinii in PCR-positive animals and infected larval ticks (38.1%), suggests that this spirochete and B. afzelii are preferentially associated with these wild canids. Although red foxes are exposed to high diversity of B. burgdorferi s.l. species found in engorged Ixodes ticks, their reservoir competence for most of them appears to be low.