title: Prevalence of spotted fever group rickettsiae in Ixodes ricinus (Acari: Ixodidae) in southern Germany.
abstract: Host-seeking Ixodes ricinus (L.) (Acari: Ixodidae) ticks were collected systematically, from May to September 2006, at selected sites in southern Germany, including a large city park in Munich. Polymerase chain reactions for amplification of genes of the rickettsial citrate synthase (gltA), the outer membrane proteins A and B (ompA and ompB), and the 16S rDNA were used to investigate 2,861 specimens (adults and nymphs). GltA sequences of spotted fever group rickettsiae were detected in 151 of all samples (5.3%; 95% CI = 4.3-6.2%). Sequencing revealed Rickettsia helvetica in 91.4% of the samples and R. monacensis in 8.6%. Amplification of ompA was not possible for R. helvetica, but in all except one of the R. monacensis. The results were analyzed statistically to test the effects of season, location, developmental stage, and gender of the tick on prevalence of Rickettsia spp. Although rickettsial DNA was detected in all investigated sites, sites in natural forest areas had significantly higher prevalences than sites in landscaped city parks. Adult female and male ticks had a similar prevalence and were significantly more often infected than nymphs. Monthly differences were not statistically significant. These results clearly show that R. helvetica is widespread throughout the study region and could result in a threat to public health in areas of high prevalence.
authors.affiliation: Institute for Comparative Tropical Medicine and Parasitology, Leopoldstr. 5, Ludwig-Maximilians-University, 80802 Munich, Germany. cornelia.silaghi@tropa.vetmed.uni-muenchen.de
authors.forename: Cornelia
authors.initials: C
authors.lastname: Silaghi
authors.forename: Jérémie
authors.initials: J
authors.lastname: Gilles
authors.forename: Michael
authors.initials: M
authors.lastname: Höhle
authors.forename: Ingrid
authors.initials: I
authors.lastname: Pradel
authors.forename: Frank T
authors.initials: FT
authors.lastname: Just
authors.forename: Volker
authors.initials: V
authors.lastname: Fingerle
authors.forename: Helmut
authors.initials: H
authors.lastname: Küchenhoff
authors.forename: Kurt
authors.initials: K
authors.lastname: Pfister
mesh_terms: D000818:Animals; D005798:Genes, Bacterial; D005858:Germany; D018884:Ixodes / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012281:Rickettsia / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D012336:RNA, Ribosomal, 16S