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Between 1942 and 1972, there were less than about 600 cases of Rocky Mountain Spotted Fever a year in the United States.
From 1972 and 1975, the number of cases reported per year rose steadily from approximately 600 to 1000 cases per year.
1975 to 1995 saw a decline in the number of cases, from more than 1000 cases, to less than 600 cases per year.
Between 1995 and 1996, the number of cases increased from approximately 600 to 800 cases reported per year.
Date last reviewed: 05/20/2005 |