First isolation of Rickettsia slovaca from Dermacentor marginatus in France.

Three rickettsial strains isolated from Dermacentor marginatus ticks in southern France in 1991 were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting with polyclonal mouse antisera, microimmunofluorescence serologic typing, and the polymerase chain reaction followed by analysis of restriction fragment length polymorphisms. By these methods, the isolates appear to be identical to the spotted fever group rickettsia, Rickettsia slovaca, which has so far been found only in Czechoslovakia. The fact that this rickettsial strain of unknown pathogenicity may occur in the same regions where R. conorii is endemic is of particular epidemiologic importance.