Rocky Mountain spotted fever

Rocky Mountain spotted fever, infectious disease caused by a rickettsia. The germ is harbored by wild rodents and other animals and is carried by infected ticks that attach themselves to humans. Despite its name, Rocky Mountain spotted fever is most prevalent in the S United States from Virgina, the Carolinas, and Georgia W to Oklahoma; it may be encountered in other tick-infested regions. Symptoms include chills and high fever; a rose-colored skin rash that appears first on the wrists and ankles and spreads to the trunk, the spots turning deep red and running together; headache; and pains in the back, muscles, and joints. In severe cases there may be delirium or coma. Spotted fever is a serious disease; however, it is not usually fatal if prompt antibiotic treatment is administered. Immunization with vaccine is effective.

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Rocky Mountain spotted fever

Typhus-like disease first seen in the Rocky Mountain region, caused by the bacterium Rickettsia rickettsii (see rickettsia) and transmitted by various ticks. In severe cases the rash bleeds more and is especially prominent on the wrists and ankles. Central nervous system involvement causes restlessness, insomnia, and delirium. Prostration may progress to coma, with death possible in a week or more. Mortality increases with age. Recovery is slow but usually complete as visual disturbances, deafness, and mental confusion pass. Prompt antibiotic treatment hastens it and reduces mortality. Prevention depends on avoiding tick bites, by wearing long, light-coloured clothing and insect repellent and inspecting for ticks. A vaccine reduces the risk of infection somewhat and of death greatly.