Identification of four Borrelia burgdorferi sensu lato species in Ixodes ricinus ticks collected from Dutch dogs

The prevalence of Borrelia species infection was determined by polymerase c hain reaction (PCR) in 138 ticks collected from dogs which were walked regu larly in the wooded areas near the city of Eindhoven, the Netherlands. The PCR amplified the spacer region between the 5S and 23 S rRNA genes, and the Borrelia species was identified by hybridization with specific probes. Bor relia burgdorferi sensu late was present in 20 of 138 (14.5%) ticks, Four s pecies were identified: B. burgdorferi sensu stricto (n = 8), B. afzelii (n = 4), B. garinii (n = 2), and B, valaisiana (n = 2). One PCR product was n on-typeable. Three ticks contained more than one species, all including B. burgdoferi sensu stricto, and one tick even contained four species. There w as a significant difference (P < 0.05) in prevalence of B. burgdorferi sens u stricto between non-engorged ticks (either questing or attached) and semi -engorged ticks, 12% (10 of 85) and 2% (1 of 53), respectively.