Rhipicephalus ticks infected with Rickettsia and Coxiella in Southern Switzerland (Canton Ticino)

Abstract

Ticks of the Rhipicephalus sanguineus species complex may be vector of various pathogens including Rickettsia conorii (the etiological agent of the Mediterranean spotted fever) and Coxiella burnetii (cause of the Query (Q) fever). R. sanguineus ticks have been imported in several parts of central and northern Europe, especially in environments such as kennels and houses providing the appropriate microclimatic conditions and the blood source necessary for their survival. Since 1940 these ticks have occasionally been recorded in Switzerland. In Ticino (the southern part of Switzerland), they have been reported since 1980 and their probable establishment in this area has been suggested in the '90s. By means of PCR and direct sequencing, we tested the identity of these ticks (using 12S rDNA gene) and the occurrence of Rickettsia spp. (using 16S rDNA, gltA and OmpA genes) as well as Coxiella sp. (using 16S rDNA). The results indicated that in Ticino, two different tick species coexist, i.e. R. sanguineus sensu stricto and Rhipicephalus turanicus. A few individuals of R. sanguineus sensu stricto are infected with Rickettsia massiliae/Bar29, which are strains of unknown pathogenicity. Coxiella sp., an endosymbiont of Rhipicephalus ticks, has also been identified in both tick species. Due to climatic changes towards global warming, imported tick species may therefore adapt to new area and might be considered as epidemiological markers for a number of infectious agents transmitted by them.