Prevalence of antibodies to spotted fever group rickettsiae along the eastern coast of the Adriatic sea.

A seroepidemiological survey in coastal Croatia detected antibodies reactive with Rickettsia conorii in 4.2% of sera by immunofluorescence assay and in 5.0% of sera by enzyme immunoassay. Western immunoblotting demonstrated antibodies to the 120-kDa surface protein in all 20 positive serum samples examined and to rickettsial lipopolysaccharide in 3 of these serum samples. Humans in this area are clearly being exposed to spotted fever rickettsiae.