Rocky Mountain spotted fever

Rocky Mountain spotted fever, acute febrile disease caused by Rickettsia rickettsii and transmitted by ixodid ticks. The onset is abrupt, with severe headache, chills, and muscular pains. Fever reaches 40°C (104°F) within several days and remains high for 10 to 15 days. Untreated patients may develop pneumonia, tissue necrosis, and circulatory failure, with resulting brain and heart damage. Starting antibiotic therapy early has significantly reduced mortality, formerly about 20 percent.

See also: Rickettsia.