Rocky Mountain spotted fever in the United States, 1997-2002.

Rocky Mountain spotted fever (RMSF) is the most commonly reported fatal tick-borne disease in the United States. During 1997–2002, 3,649 cases of RMSF were reported to the Centers for Disease Control and Prevention via the National Electronic Telecommunications System for Surveillance; 2,589 case report forms, providing supplemental information, were also submitted. The average annual RMSF incidence during 1997–2002 was 2.2 cases/million persons. The annual incidence increased during 1997–2002 to a rate of 3.8 cases/million persons in 2002. The incidence was lowest among persons aged <5 and 10–29 years, and highest among adults aged 60–69 years. The overall case-fatality rate was 1.4%; the rate peaked in 1998 at 2.9% and declined to 0.7% in 2001 and 2002. Children <5 years of age had a case-fatality rate (5%) that was significantly greater than the rates for age groups <60 years of age, except for that for 40–49 years of age. Continued national surveillance is needed to assess the effectiveness of prevent...