Fatal cases of Rocky Mountain spotted fever in family clusters--three states, 2003.

Rocky Mountain spotted fever (RMSF), a tickborne infection caused by Rickettsia rickettsii and characterized by a rash, has a case-fatality rate as high as 30% in certain untreated patients. Even with treatment, hospitalization rates of 72% and case-fatality rates of 4% have been reported. This report summarizes the clinical course of three fatal cases of RMSF in children and related illness in family members during the summer of 2003. These cases underscore the importance of 1) prompt diagnosis and appropriate antimicrobial therapy in patients with RMSF to prevent deaths and 2) consideration of RMSF as a diagnosis in family members and contacts who have febrile illness and share environmental exposures with the patient.