Characteristics of garden dormice that contribute to their capacity as reservoirs for Lyme disease spirochetes

To describe the contribution of garden dormice to the epizootiology of Lyme disease, we compared their reservoir capacity for these pathogens to that off other sympatric hosts. Garden dormice are trapped most abundantly durin g early spring and again during midsummer, when their offspring forage. The y are closely associated with moist forests. Garden dormice serve as hosts to nymphal ticks far more frequently than do other small mammals. Spirochet al infection is most prevalent in dormice, and many more larval ticks acqui re infection in the course of feeding on these than on other rodents in the study site. Mature dormice appear to contribute more infections to the vec tor population than juveniles do. Replete larval ticks generally detach whi le their dormouse hosts remain within their nests. The population of garden dormice contributes five- to sevenfold more infections to the vector popul ation than the mouse population does. Their competence, nymphal feeding den sity, and preference for a tick-permissive habitat combine to favor garden dormice over other putative reservoir hosts of Lyme disease spirochetes.