Frequent occurrence of hepatic lesions in boutonneuse fever

Seven consecutive Sicilian patients with boutonneuse fever but without clinical symptoms of hepatic disease underwent hepatic biopsy and had similar hepatic lesions. Foci of hepatocellular necrosis were infiltrated with predominantly mononuclear leukocytes. No intact Rickettsia conorii were identified in the tissues by immunofluorescence. The apparent high frequency of viscerotropism in boutonneuse fever conforms to the recent observations of severe illness in what had often been described previously as a benign rickettsiosis.