Epidemiology of boutonneuse fever in western Sicily: demonstration of multiple spotted fever group-Rickettsiae subtypes.

Electrophoretic analysis of the proteins and genomic DNA of spotted fever-group Rickettsiae isolated from ticks and a human in Western Sicily show that at least two distinct subtypes other than R. conorii are present in this region. All of the spotted fever-group isolates share common features with other, well-defined spotted fever-group rickettsial species, e.g. R. sibirica, Thai Tick Typhus, and R. rickettsii. Based on these data, caution is recommended when identifying species by the more traditional and less specific tests. Studies of the ecology and epidemiology of spotted fever-group Rickettsiae in regions where R. conorii infections occur would benefit and be challenged by intensive antigenic analyses of the proteins and genomic DNA of the various strains of the spotted fever-group Rickettsiae present in those areas.