Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) was first recognized as a human disease in Idaho in 1896. It is a very serious, potentially fatal disease, caused by a bacterium that is an intracellular parasite of cells lining blood vessels. Since its discovery, between 250-1,200 cases of RMSF have been diagnosed each year, with only 1-3% of cases in the Rocky Mountains. Nearly all cases over the past several decades have occurred east of the Mississippi River. RMSF derives its name from the characteristic rash that develops in from 35-60% of diagnosed patients. The rash (non-itching) consists of countless tiny red spots that initially appear on the hands and feet, but later become more widespread, including on the soles of the feet.
- A bacterium with the scientific name Rickettsia rickettsii.
- Rickettsia species multiply inside cells lining small and medium blood vessels, eventually destroying them.
- South America, Central America, Mexico, southern Canada, and the continental United States.
- The vast majority of cases in the U.S. occur in the mid-Atlantic and southeastern states, especially in North Carolina and Oklahoma, but cases are documented throughout Indiana.
- Fever, headache, joint pain, muscle ache, nausea, and possibly abdominal pain and diarrhea.
- 35-60% of patients develop a rash of non-itchy, tiny reddish spots that initially appear on hands and ankles, but eventually develop on the forearms and soles of the feet.
- Severe cases involve delirium and coma, with a fatality rate of 3-5% (nearly 30% in untreated patients).
- Small rodents, including deer mice and meadow voles.
- From infected ticks, usually female adults, to humans via their bite.
- From infected tick larvae to nymphs to adults via transstadial transmission.
- From infected female ticks to their eggs via transovariole transmission.
- NOTE: there is no human-to-human transmission.
- Symptoms, especially the characteristic rash, together with onset in late spring-summer following tick bite.
- Antibiotic prescribed by a physician.