Rocky Mountain Spotted Fever

Rocky mountain spotted fever is an illness caused by the bacteria rickerttsia ricketsii and is spread by the bite of ticks. The illness is characterized by fever, body aches, a typical rash about the ankles & wrists progressing to severe infection and death if untreated.

Where does it occur?

It occurs throughout the United States with the highest incidence in the South Atlantic and South Central States with the greatest incidences reported from Oklahoma and North Carolina. There has been a recent outbreak in eastern Arizona. Outside the United States it is seen in Canada, Central and South America.

How is it transmitted?

It is transmitted through the bite of infected ticks; namely dog ticks and rocky mountain wood ticks. Generally the tick needs to be attached to the person for 4-6 hours to contract the infection.

Is it contagious from person to person?

The infection is not spread from person to person.

What is the risk for travelers?

The risk for travelers is generally low; risk is higher if engaged in extensive outdoor activities in high risk areas.

How soon after exposure will one develop symptoms?

Symptoms appear anywhere from 2 days to 2 weeks after exposure, but are usually seen within a week of the tick bite.

What are the signs and symptoms?

Symptoms start with high fever, intense muscle aches, joint pains and headache. Many also report abdominal pain, nausea, vomiting and diarrhea. Three to five days after the onset of fever a typical rash that is red in color and varies from flat to prickly in nature starting around the ankles and wrists and spreading to involve the soles and palms. The rash may not be present in older individuals or noticeable in darker pigmented individuals.

If untreated the illness progresses to involve the central nervous system with features of severe headache, stiff neck, decreased level of consciousness, paralysis and multiple organ failure with lung and kidney involvement leading to death.

Are there any lab tests to diagnose the illness?

Blood antibody tests (IgM/IgG) and cultures are available but take time to get results. Early diagnosis is still based on signs/symptoms in the setting of a high clinical suspicion based on travel and exposure history.

Is there any treatment?

The antibiotic tetracycline is the drug of choice.

What preventive measures can be taken?

Avoid tick bites, if ticks are seen on the body promptly remove them, watch for any signs and symptoms and seek medical attention.

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