Rocky Mountain Spotted Fever

Rocky Mountain spotted fever is an acute infectious disease transmitted to humans by the bite of an infected tick. The disease occurs throughout the United States during months when ground temperatures reach 40 degrees Fahrenheit or more and ticks are active.

Both children and adults can be affected by Rocky Mountain spotted fever. Disease incidence is directly related to exposure to tick-infested habitats or to infested pets. In spite of the disease's name, few cases have been reported from the Rocky Mountain region of the United States.

Rocky Mountain spotted fever is spread by the bite of an infected tick (the American dog tick or the lone-star tick) or by contamination of the skin with tick blood or feces. Person-to- person transmission does not occur.

Rocky Mountain spotted fever is characterized by a sudden onset of moderate to high fever (which can last for two or three weeks), severe headache, fatigue, deep muscle pain, chills and rash. The rash begins on the legs or arms, may include the soles of the feet or palms of the hands and may spread rapidly to the trunk or the rest of the body. Not every case of Rocky Mountain spotted fever will have the rash.

Symptoms usually appear between three and 14 days after the bite of an infected tick. Any person experiencing illness with a fever following a tick bite should consult his or her physician and advise the physician of the tick bite.

Diagnosis of Rocky Mountain spotted fever is based largely on the patient's signs and symptom's of illness. Blood tests are important in confirming a diagnosis, but treatment should begin promptly if symptoms and exposure history support this diagnosis.

Treatment involves the use of certain antibiotics, such as tetracycline or chloramphenicol. Antibiotic treatment can be terminated two or three days after a person's temperature returns to normal for a full 24-hour period. Overall mortality hovers between 3 percent and 5 percent but ranges from 13 percent to 25 percent in untreated individuals. Death primarily occurs in patients in whom the diagnosis is not made until the second week of illness. The absence or delayed appearance of the typical rash contributes to a late diagnosis and thereby increases the incidence of fatality.

Persons spending time outdoors in areas where ticks are commonly found — wooded areas, tall grass and brush — should take precautions against all tickborne diseases:

• Check your clothing often for ticks climbing toward open skin. Wear white or light-colored long-sleeved shirts and long pants so the tiny ticks are easier to see. Tuck long pants into your socks and boots. Wear a head covering or hat for added protection.
• For those who may not tolerate wearing all of these clothes in hot, muggy weather, apply insect repellent containing DEET (30 percent or less) to exposed skin (except the face). Be sure to wash treated skin after coming indoors. If you do cover up, use repellents containing permethrin to treat clothes (especially pants, socks and shoes) while in locations where ticks may be common. Follow label directions; do not misuse or overuse repellents. Always supervise children in the use of repellents.
• Walk in the center of trails so weeds do not brush against you.
• Check yourself, children and other family members every two to three hours for ticks. Most ticks seldom attach quickly and rarely transmit tickborne disease until they have been attached for four or more hours.
• If you let your pets outdoors, check them often for ticks. Infected ticks also can transmit some tickborne diseases to them. (Check with your veterinarian about preventive measures against tickborne diseases.) You are at risk from ticks that "hitch a ride" on your pets but fall off in your home before they feed.
• Make sure the property around your home is unattractive to ticks. Keep your grass mowed and keep weeds cut.

Remove any tick promptly. Do not try to burn the tick with a match or cover it with petroleum jelly or nail polish. Do not use bare hands. The best way to remove a tick is to grasp it with fine-point tweezers as close to the skin as possible and gently, but firmly, pull it straight out. Do not twist or jerk the tick. If tweezers are not available, grasp the tick with a piece of cloth or whatever can be used as a barrier between your fingers and the tick. You may want to put the tick in a jar of rubbing alcohol labeled with the date and location of the bite in case you seek medical attention and your physician wishes to have the tick identified.

The mouthparts of a tick are shaped like tiny barbs and may remain embedded and lead to infection at the bite site if not removed properly.
Be sure to wash the bite area and your hands thoroughly with soap and water, and apply an antiseptic to the bite site.

• Rocky Mountain Spotted Fever Training Module: Clinical Diagnosis and Treatment for Healthcare Providers (Continuing Education)
• IQuery
• Vector Control & Surveillance
• Tickborne Diseases of the United States, Reference Manual for Health Care Providers
• Information for Hunters on Ticks
• Tick Identification
• Rocky Mountain Spotted Fever Toolkit for Health Care Providers
• Rocky Mountain Spotted Fever Data & Statistics