TRANSMISSION CYCLES OF BORRELIA-BURGDORFERI SENSU-LATO INVOLVING IXODES-RICINUS AND OR I-HEXAGONUS TICKS AND THE EUROPEAN HEDGEHOG, ERINACEUS-EUROPAEUS, IN SUBURBAN AND URBAN AREAS IN SWITZERLAND/

European hedgehog, Erinaceus europaeus Linnaeus, 1758, is a common hos t of Ixodes ricinus L, and I. hexagonus Leach, vectors of the Lyme dis ease spirochaete, Borrelia burgdorferi sensu lato. TO investigate whet her hedgehogs are reservoirs for B. burgdorferi, hedgehogs were captur ed in a suburban area suitable for both tick species and in an urban a rea where I, ricinus is absent. The infection status of the hedgehogs was determined by xenodiagnosis using I. ricinus and I. hexagonus larv ae. I. hexagonus and/or I. ricinus were found on;ll hedgehogs (n = 8) from the suburban area. In contrast, only I. hexagonus was infesting a nimals (n = 5) from the urban area. A total of 12/13 hedgehogs harbour ed B. burgdorferi infected ticks. Xenodiagnostic I. ricinus and I. hex agonus larvae that fed on hedgehogs became infected. The results clear ly show that European hedgehogs are reservoir hosts of the Lyme diseas e spirochetes. DNA of B. burgdorferi sensu stricto, B. garinii and B. afzelii was detected in culture from ear biopsy and needle aspiration material and characterized by using a genospecies-specific PCR assay. One hedgehog presented a mixed infection of the skin with B, burgdorfe ri sensu stricto and B. garinii. This study also identifies an enzooti c transmission cycle in an urban area involving E. europaeus and I. he xagonus. The close association of I. hexagonus with the burrows of its hosts mean that the risks of contact between I. hexagonus and humans may be low.