Summary about Disease
Rocky Mountain Spotted Fever (RMSF) is a tick-borne disease caused by the bacterium Rickettsia rickettsii. It is a serious illness that can be fatal if not treated early and appropriately. While the name suggests it's limited to the Rocky Mountain region, it occurs throughout North, Central, and South America.
Symptoms
Early symptoms of RMSF often include:
Fever
Headache
Muscle pain
Nausea
Vomiting
Lack of appetite A characteristic rash typically develops a few days after the onset of fever, often starting on the wrists and ankles and spreading to the trunk. The rash may initially look like small, flat, pink spots that eventually become raised and may become purplish. Note: The rash is not always present, especially in the early stages.
Causes
RMSF is caused by the bacterium Rickettsia rickettsii. This bacterium is transmitted to humans through the bite of an infected tick. The most common ticks that transmit RMSF in the United States are the American dog tick, Rocky Mountain wood tick, and brown dog tick.
Medicine Used
The primary and most effective treatment for RMSF is the antibiotic doxycycline. Treatment should be initiated as soon as possible when RMSF is suspected, even before confirmatory lab results are available. Delaying treatment can lead to severe complications and death. Other tetracycline-class antibiotics may be used if doxycycline is not available. Chloramphenicol is an alternative antibiotic, especially for individuals who cannot tolerate tetracyclines, but it has potential side effects.
Is Communicable
RMSF is not communicable from person to person. It is only transmitted through the bite of an infected tick.
Precautions
Avoid tick-infested areas: When possible, stay on cleared paths and avoid wooded and bushy areas with high grass and leaf litter.
Use insect repellent: Apply insect repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone to exposed skin and clothing.
Wear protective clothing: Wear long sleeves, long pants tucked into socks or boots, and a hat.
Check for ticks: After spending time outdoors, thoroughly check yourself, your children, and your pets for ticks. Pay close attention to areas under the arms, in and around the ears, inside the belly button, behind the knees, in the hair, between the legs, and around the waist.
Remove ticks promptly and properly: Use fine-tipped tweezers to grasp the tick as close to the skin's surface as possible. Pull upward with steady, even pressure. Do not twist or jerk the tick. After removing the tick, clean the bite area and your hands with rubbing alcohol or soap and water.
Shower soon after being outdoors: Showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease and may be effective in reducing the risk of other tick-borne diseases.
Treat clothing and gear: Use products containing permethrin to treat clothing and gear, such as boots, pants, socks and tents.
How long does an outbreak last?
RMSF is not characterized by outbreaks in the traditional sense of a contagious disease spreading rapidly through a population. Instead, cases occur individually, or in small clusters, depending on tick activity and human exposure. The "season" for RMSF generally aligns with the activity of ticks, which is typically from April to September, but can vary depending on the geographic location and climate. Cases can occur year-round, though less frequently outside of the typical tick season. The duration of illness for an individual is usually several weeks, if untreated, but resolves within a few days to weeks with appropriate antibiotic treatment.
How is it diagnosed?
Diagnosing RMSF can be challenging because early symptoms are similar to those of other diseases. Diagnosis is primarily based on clinical signs and symptoms, along with a history of possible tick exposure. Diagnostic tests include:
Blood tests: Blood tests can detect antibodies to R. rickettsii, but these may not be positive until several days or weeks after the onset of illness.
Skin biopsy: A skin biopsy of the rash can be tested for the presence of R. rickettsii using immunohistochemical staining.
PCR tests: Polymerase chain reaction (PCR) tests can detect the DNA of R. rickettsii in blood or tissue samples. Because waiting for lab results can delay treatment, healthcare providers often start antibiotic therapy based on clinical suspicion and history.
Timeline of Symptoms
Days 1-4 (Early Symptoms): Fever, headache, muscle pain, nausea, vomiting, loss of appetite.
Days 3-5 (Rash Development): Rash appears, usually starting on wrists and ankles and spreading to the trunk. The rash may initially look like small, flat, pink spots.
Days 5-14 (Progression of Illness if Untreated): The rash can become more prominent and may involve the palms and soles. Symptoms worsen, and complications can develop, including organ damage, neurological problems, and death.
With Treatment: Symptoms typically begin to improve within 24-48 hours of starting appropriate antibiotic therapy. The rash may take longer to fade.
Important Considerations
Early diagnosis and treatment are critical to prevent severe complications and death.
RMSF can be fatal if left untreated, especially in children and older adults.
Anyone with a fever, headache, rash, and history of possible tick exposure should seek medical attention immediately.
Even if a tick bite is not remembered, the possibility of RMSF should be considered if the symptoms are present, especially during the tick season.
Pregnant women should be treated with doxycycline, as the benefits of treatment outweigh the risks.
Awareness and prevention measures are key to reducing the incidence of RMSF.