What Is It?
Rocky Mountain spotted fever is a severe illness caused by tiny bacteria called Rickettsia rickettsii, which are transmitted through the bite of an infected tick. In the eastern United States and in California, the infected tick is usually Dermacentor variabilis, the American dog tick. In most of the western United States, the tick is more likely to be Dermacentor andersoni, the Rocky Mountain wood tick. Humans typically become infected in the spring and early summer.
Once someone is bitten by an infected tick, Rocky Mountain spotted fever bacteria have the potential to spread throughout the bloodstream and lymphatic system. The tick must remain attached and be actively feeding to transmit the bacteria. Not everybody who is bitten by an infected tick develops Rocky Mountain spotted fever. It is not clear why some people get the disease and others do not.
Symptoms
Typically symptoms begin 2 to 14 days after a tick bite, with an average of 1 week. During the first 3 days of symptoms, an infected person usually has a fever of greater than 102 degrees Fahrenheit and severe headache. Muscle aches, nausea and vomiting are common. Between the 3rd and 5th day of fever, most people develop a rash, which usually begins on the wrists and ankles, then spreads to the arms, legs and trunk. In about two-thirds of patients, the rash also involves the palms of the hands and the soles of the feet. On day 6 or later, the areas of rash may show tiny broken blood vessels and small hemorrhages under the skin.
Other symptoms of Rocky Mountain spotted fever include:
* Lungs — Rapid breathing, severe shortness of breath, bluish tint to fingernails and lips
* Liver and gastrointestinal tract — Abdominal pain, nausea, vomiting, diarrhea and jaundice
* Brain — Confusion, lethargy, difficulty walking, extreme drowsiness, seizures and coma
Prevention
Because there is no vaccine against Rocky Mountain spotted fever, the most effective way to prevent the illness is to avoid walking in wooded areas or fields where ticks are found. If you must walk in tick-infested areas, follow these precautions:
* Wear light-colored clothing, which allows you to promptly identify a clinging tick.
* Wear long-sleeved shirts and pants that are snug around the wrists and ankles.
* While you are outdoors, check yourself for ticks every two hours.
* Use an approved tick repellent.
* If you find a tick on your body, remove it immediately with tweezers, then wash your hands thoroughly.
Treatment
Rocky Mountain spotted fever is treated with doxycycline (generic). Because doxycycline can stain the teeth of young children, it is not recommended for pregnant women and children under the age of 9. However, doxycycline is the best available antibiotic. An alternative antibiotic for pregnant women and very young children is chloramphenicol (Chloromycetin).
Most people are cured after taking the antibiotics for five to seven days. Patients may need to be hospitalized if there is severe lung damage, kidney failure, significant bleeding or severe brain involvement. In cases of respiratory failure, mechanical ventilation (treatment with a machine that breathes for the patient) may be necessary. Patients with kidney failure may require dialysis. Those with severe bleeding may need blood transfusions.
