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Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever Facts

  • Rocky Mountain spotted fever is a disease caused by bacteria that are transmitted by tick bites to humans.
  • The disease is not contagious from person to person.
  • The disease is caused by bacteria termed Rickettsia.
  • Three major signs and symptoms are tick bite, fever, and rash; other symptoms may also develop.
  • Medical care should be sought if Rocky Mountain spotted fever disease is suspected.
  • Diagnosis is usually made based upon the patient's history and symptoms, but specific tests are available.
  • Although primary-care physicians can treat the disease, other specialists may be consulted.
  • Treatment is done with antibiotics, usually doxycycline and occasionally, chloramphenicol.
  • Prevention of the disease involves avoiding the risk factor of tick bites.
  • The prognosis of the disease is good if treated early.
  • Published procedures indicate how to safely remove a tick attached to the skin.
  • Rocky Mountain spotted fever is found in many areas; the disease is not limited to the Rocky Mountain area of the U.S.

What Is Rocky Mountain Spotted Fever?

Rocky Mountain spotted fever (RMSF) is a disease caused by the bacteria Rickettsia rickettsii (transmitted by tick bites to humans) that has nonspecific symptoms of fever, chills, headache, and muscle aches with progression to a rash about five to 10 days after an initial bite by an infected tick. RMSF is the most common fatal tick-transmitted disease in the U.S. Worldwide, there are about 18 other closely related Rickettsia species belonging to a group (spotted fever group) that cause a similar disease process known by many different names (for example, Boutonneuse fever, African tick bite fever, Japanese spotted fever). RMSF was first diagnosed in 1896 in Idaho and was first named "black measles" but then was termed Rocky Mountain spotted fever. In 1906, Howard Ricketts showed that ticks were vectors (carriers) of the pathogenic bacteria and in 1909 showed evidence that bacteria (later named after him) caused the disease. Ticks can act as vectors for many diseases (for example, Lyme disease, tularemia, Q fever) in addition to RMSF.

Picture of female and male wood ticks
Picture of female and male wood ticks; Source: CDC
Medically Reviewed by a Doctor on 10/21/2016

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Tick Bite Prevention

  • Avoid grassy areas and shrubs where ticks may be lying in wait to tag a ride on a potential "meal."
  • Avoid tick season completely by staying away from outdoor areas where ticks thrive, usually during the months of April through September in the U.S.
  • Wear light-colored clothing so ticks can be easily seen, and brush them off.
  • Tuck pants into boots or socks.
  • Apply insect repellant, specifically the brands designed to repel ticks. Follow label instructions. Avoid use of DEET-containing repellents on children. Carefully follow instructions and apply some repellents directly to skin and others to clothing.

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