Sand and Common Lizards (Lacerta agilis and Zootoca vivipara) Infested with Immature Ixodes ricinus Ticks Preferentially Maintain the Circulation of Borrelia lusitaniae and B. burgdorferi Sensu Stricto in Anthropogenic Areas of Western Poland

This study was conducted to assess the involvement of two lizard species: the sand lizard (L. agilis) and the common lizard (Zootoca vivipara), and their Ixodes ricinus ticks, in the circulation spirochetes of the Borrelia burgdorferi s.l. complex. Lizards were captured at three study sites in suburban areas of western Poland. Common lizards were less abundant and occurred only at one site. A total of 1,129 ticks were collected from 167 sand lizards and 164 individuals from 42 common lizards. Biopsies of the distal part of the lizard tail were taken from 172 animals. All samples that tested positive by real-time PCR underwent subsequent nested PCR targeting the flaB gene, followed by sequencing. At least 6.3% of I. ricinus ticks (MIR) from L. agilis, and 6.1% from Z. vivipara, were infected. Borrelia lusitaniae was the most prevalent species in L. agilis-derived ticks, accounting for 73.2% of all infected samples, followed by B. burgdorferi s.s. (23.0%). Conversely, this latter species prevailed (90%) over B. lusitaniae (10%) in tick samples from Z. vivipara. Therefore, we believe that sand lizards are competent reservoir hosts for B. lusitaniae, while the role of Z. vivipara for this species is unclear. The high prevalence of B. burgdorferi s.s. was also found in infected larval samples (40.7%) and biopsies (60%) of L. agilis. Thus, in our opinion, these two lizard species could be another group of reservoir hosts for this human pathogen, along with birds and rodents.