Definition Rocky Mountain spotted fever is an infection with fever and rash. It is usually transmitted from a bite of an infected tick.
What is going on in the body? Rocky Mountain spotted fever occurs mainly in the southeast and south central part of the US. It is found most often in Texas, Oklahoma, and Arkansas. It is more common in the spring and summer. The organism that causes the fever, Rickettsia rickettsii, is transmitted to humans through the bite of a tick. The species of tick involved may vary, depending on the location.
What are the signs and symptoms of the infection? The time from tick bite to symptoms of Rocky Mountain spotted fever ranges from 2 days to 2 weeks. The typical symptoms include:
a rash that begins sometime before the sixth day of illness
The rash starts on the hands and feet, including the palms and soles. It then spreads to the ankles, wrists, abdomen, and trunk.
What are the causes and risks of the infection? Rickettsia rickettsii is the organism that causes Rocky Mountain spotted fever.
When an infected tick bites or burrows into a person's skin, the infection can be spread. The organism is also found in squirrels, chipmunks, and rodents. The tick may be seen in any area, urban or rural, with heavy brush. This infection may also be spread by blood transfusion from an infected person.
What can be done to prevent the infection? The best way to reduce the risk of Rocky Mountain spotted fever is to reduce exposure to ticks. This can be done by:
avoiding tick-infested areas
wearing protective clothing
using insect repellents
inspecting the body for ticks after spending time outdoors
promptly removing attached ticks
How is the infection diagnosed? Currently there is no reliable test for diagnosing Rocky Mountain spotted fever, so diagnosis is made on the basis of symptoms and the history. The season of the year and where the person has been recently are taken into account. After the acute phase of the disease, blood test called an antibody titre can be done to measure antibodies to the organism in the person's blood. At times a skin biopsy may be done to identify the infecting organism.
What are the long-term effects of the infection? If treatment is not started early in a person with Rocky Mountain spotted fever, there may be complications. Long-term effects may involve:
Serious complications include blood clotting problems and low blood pressure, both of which can lead to death. Long-term effects, including death and neurologic damage, are not uncommon in severe cases of Rocky Mountain spotted fever.
What are the risks to others? Rocky Mountain spotted fever is acquired by a tick bite. It is not spread directly from person to person, but can be spread through blood transfusions.
What are the treatments for the infection? Early treatment is crucial for Rocky Mountain Spotted Fever. Treatment includes:
use of a ventilator, or artificial breathing machine, for severe respiratory distress
close monitoring for kidney or liver problems, or secondary lung infection
antibiotics, such doxycycline
What are the side effects of the treatments? Possible side effects of doxycycline and other antibiotics include stomach upset, allergic reactions, and liver problems. These antibiotics may also cause discolouration of the teeth in children less than 8 years old.
What happens after treatment for the infection? The earlier treatment is started for Rocky Mountain spotted fever, the shorter the recovery time. Bed rest may be needed for several days to several weeks. Activity can be gradually increased.
How is the infection monitored? A person being treated at home for Rocky Mountain Spotted Fever should monitored closely for several symptoms. These include increased fever, tenderness in the abdomen, difficulty urinating, and increased weakness. If seizures or confusion develop, immediate medical attention should be sought. Any other new or worsening symptoms should also be reported to the healthcare doctor.
Author: Danielle Zerr, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 19/06/2005 Contributors Potential conflict of interest information for reviewers available on request
