Disease Control and Environmental Epidemiology Division

Rocky Mountain Spotted Fever

Rocky Mountain spotted fever is a serious disease that is transmitted by infected Rocky Mountain wood ticks. The initial symptoms, which follow an incubation period of 3 to 14 days, are "flu-like": there may be sudden onset of high fever, headache, chills, and muscle aches. A rash often appears a few days later. This rash spreads rapidly over the entire body and may even be seen on the palms of the hands and soles of the feet. Prompt medical attention is extremely important because Rocky Mountain spotted fever can be fatal if treatment is delayed. The illness can be cured with antibiotics.

What Causes Rocky Mountain Spotted Fever?

Ticks can carry spotted fever organisms (rickettsia). Hungry ticks usually position themselves on grass or small bushes and wait for a potential host to pass by. If the tick drops onto a human's legs, it often crawls upward toward the head looking for a place to attach. Ordinarily infection takes place when disease-causing rickettsia are inoculated into the skin via the bite of a feeding tick. Quick removal of ticks is important because they often must be attached several hours before there is disease transmission. People who remove ticks from domestic animals can also become infected if they crush ticks between their fingers, causing rickettsia to penetrate the skin. Thus, whenever ticks are handled, it is important to wash hands immediately. The disease can occur year around.

How is Rocky Mountain Spotted Fever Diagnosed?

It is important to notify a physician if you become ill after an exposure to ticks. A diagnosis of Rocky Mountain spotted fever will be based on clinical signs and symptoms and is confirmed by positive laboratory test results.

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