Rickettsial antibody in southern France: antibodies to Rickettsia conorii and Coxiella burnetii among urban, suburban and semi-rural blood donors.

Three hundred and twenty-five sera from blood donors in the south of France were examined by means of the indirect fluorescent antibody test. 18% of the sera had antibodies to Rickettsia conorii, with a significantly higher prevalence (26%) in urban and suburban areas than in semi-rural areas (13 to 16%). This supports the view that in the south of France the highest prevalence of Mediterranean Spotted Fever is suburban. 5% of the sera had antibodies to Coxiella burnetti in this area, in which Q fever is endemic.