To explore increased risk for human Rickettsia spp. infection in Germany, we investigated recreational areas and renatured brown coal surface-mining sites (also used for recreation) for the presence of spotted fever group rickettsiae in ticks. R. raoultii (56.7%), R. slovaca (13.3%), and R. helvetica (>13.4%) were detected in the respective tick species.
Rickettsia species of the spotted fever group are causing emerging infectious diseases (1). Since 1977, Rickettsia slovaca, found in Dermacentor marginatus ticks, was the only known Rickettsia sp. in Germany until 2002, when the following were identified: R. monacensis and R. helvetica in Ixodes ricinus ticks, Rickettsia sp. RpA4 (now R. raoultii) in D. reticulatus ticks, R. felis in Ctenocephalides felis cat fleas, and R. massiliae in I. ricinus ticks (1,2). All of these species cause tick-borne rickettsioses in humans, including tick-borne lymphadenopathy (TIBOLA) (3–7). The aim of this study was to explore the interface between the vector tick and humans by investigating the presence of Rickettsia spp. in ticks at highly frequented recreational areas and renatured brown coal surface-mining sites that also are used for leisure.