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.

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Rocky Mountain spotted fever [′räk·ē ′mau̇nt·ən ′späd·əd ′fē·vər]

(medicine)

An acute, infectious, typhuslike disease of man caused by the rickettsial organismRickettsia rickettsiand transmitted by species of hard-shelled ticks; characterized by sudden onset of chills, headache, fever, and an exanthem on the extremities. Also known as American spotted fever; tick fever; tick typhus.

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Rocky Mountain Spotted Fever 

an acute infectious disease of man, of the group of rickettsioses. A naturally endemic disease, it is encountered in the western hemisphere.

Rocky Mountain spotted fever is usually observed in spring and summer. The causative agent is transmitted by ticks from generation to generation; other reservoirs of the virus include rodents and dogs. The disease develops within two to 14 days after the tick bite. The causative agent may also reach the skin and mucosa when the tick is crushed. The disease is manifested by high fever (39° to 41 °C) and a spotty nodular rash that appears on the second to fifth day. Other symptoms are headache, nausea, vomiting, pains in the bones and muscles, restlessness, and insomnia.

Rocky Mountain spotted fever is treated with antibiotics and oxygen therapy. It is prevented by avoiding tick bites and by disinsectization and immunization.