Epidemiology of boutonneuse fever in western Sicily: accidental laboratory infection with a rickettsial agent isolated from a tick.

A case is reported of an accidental laboratory infection with a strain of Spotted Fever-Group Rickettsiae freshly isolated from a tick collected in Western Sicily. Inoculation into the left thumb of cell-cultured organisms (10(5)/ml) gave rise to clinical signs and symptoms of Boutonneuse Fever after six days, i.e., a lesion at the point of inoculation, fever, headache, conjunctivitis and myalgias. Rickettsiae were isolated from acute-phase blood samples collected from the infected individual and IgM and IgG response was detected in the patient's serum by indirect immunofluorescence. Complete recovery was obtained after antibiotic treatment. Serologic analysis of the strain, together with analyses of the proteins of the isolate, documented that the isolate was Rickettsia conorii and was identical to prototype strain. The relationship of this infection to ongoing studies on the epidemiology of Boutonneuse Fever in Western Sicily is discussed.