How Common Are Rickettsial Infections?
These infections do not occur frequently in the United States (although typhus is relatively common in other parts of the world, especially the tropics). Rocky Mountain spotted fever is the most common rickettsial infection in the United States: up to 1,200 cases are reported yearly. Fewer than 100 typhus cases are reported annually, and a total of about 1,200 cases of ehrlichiosis have been reported during an 11-year period.
