Spotted fever group rickettsioses (spotted fevers) are a group of diseases caused by closely related bacteria. These bacteria are spread to people through the bite of infected mites and ticks. The most serious and commonly reported spotted fever group rickettsiosis in the United States is Rocky Mountain spotted fever (RMSF).

Other causes of spotted fever group rickettsioses (spotted fevers) in the United States include:

• Rickettsia parkeri rickettsiosis, caused by R. parkeri
• Pacific Coast tick fever, caused by Rickettsia species 364D
• Rickettsialpox, caused by Rickettsia akari

Spotted fevers can range from mild to life-threatening. Most people who get sick with a spotted fever other than RMSF will have an eschar (dark scab at the site of tick or mite bite), fever, headache, and rash. Doxycycline is the treatment of choice for all spotted fever infections.

Rocky Mountain spotted fever (RMSF) is spread to people through the bite of an infected tick. Symptoms of RMSF typically begin 3–12 days after the bite and often include sudden onset of headache, fever, stomach and muscle pain. Rash may develop after several days of illness. When not treated early, RMSF can get worse very quickly, and can be fatal, even in previously healthy people. Because early symptoms are often vague and can resemble so many other diseases, it can be difficult to diagnose.

Key Facts

• Doxycycline is the treatment of choice for RMSF in adults and children of all ages. It is most effective if started before the 5th day of symptoms.
• Children <10 years of age are five times as likely to die from RMSF than adults.
• RMSF can occur during any month, but the majority of cases have an illness onset during the summer months.
• North Carolina, Oklahoma, Arkansas, Tennessee and Missouri account for over 6 in 10 cases of RMSF in the United States.

Avoid Tick Bites

Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, or 2-undecanone. Always follow product instructions. Clothing and gear can be treated with 0.5% permethrin.

Protect Your Pets

Use tick control products to prevent family pets from bringing ticks into the home. Talk to your veterinarian about which product is best for your pet. Check your pets daily for ticks, especially after they spend time outdoors. If you find a tick on your dog, remove it right away.

Know the Symptoms

Typical symptoms of RMSF include fever, headache, stomach pain, and muscle pain. A rash like the one pictured here may also develop, but is often absent in the first few days, and in some patients, never develops. Never wait for the presence of a rash to suspect RMSF.

See Your Doctor Right Away

If you develop a fever or rash after having been in grassy, brushy, or wooded areas where ticks live, see your doctor immediately. Even if it isn’t RMSF, it could also be another tickborne disease. Be sure to mention if you’ve been bitten by a tick.

Prevention Tips

• Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone on exposed skin.
• Treat clothing and gear with products containing 0.5% permethrin.
• Bathe or shower as soon as possible after coming indoors to wash off and more easily find ticks that are crawling on you.
• Check yourself, your kids, and your pets for ticks daily, especially after they spend time outdoors in areas where ticks may be found.
• Remove attached ticks as soon as possible. The preferred method of removal is to grasp the tick close to the skin with tweezers or fine-tipped forceps and gently pull upward with constant pressure.

Spotted fever group rickettsioses (spotted fevers) occur worldwide and result in a broad range of illnesses, from relatively mild to life-threatening. Below are the details for some of the spotted fevers that occur outside the United States. People may become exposed to these tick borne bacteria when traveling outside of the United States, and health care providers should be aware of these illnesses in patients who have signs and symptoms common to other spotted fevers and history of travel within 2 weeks of illness onset.

The most commonly reported spotted fever reported among United States patients following international travel is African tick bite fever, caused by Rickettsia africae. Almost 90 percent of imported spotted fevers occur among travelers to sub-Saharan Africa. Another frequently identified spotted fever group rickettsiosis is Mediterranean spotted fever, caused by Rickettsia conorii.

Commercial antibody tests for RMSF can be used to confirm any spotted fever infection. However, most commercial tests are unable to distinguish among the different species of spotted fever group Rickettsia. More specialized tests can be performed at CDC laboratories. See the For Public Health Officials Page for further instructions. Spotted fever infections can range from mild to life-threatening. Doxycycline is the treatment of choice for all spotted fever infections.

Below is a table of selected tickborne spotted fevers found outside of the United States:

*Few cases are described in the peer-reviewed literature, and the clinical picture and geographic distribution might be incomplete.

Rickettsia parkeri rickettsiosis, caused by infection with R. parkeri, is spread by the Gulf Coast tick, Amblyomma maculatum, which is found in the southeastern United States.

Pacific Coast tick fever is caused by the bacteria R. philipii (known previously as Rickettsia sp. 364D). Pacific Coast tick fever is spread by the bite of infected Pacific Coast ticks, Dermacentor occidentalis, which can be found along the western coastline in California, Oregon, and Washington.

Rickettsialpox is caused by R. akari. Unlike the other spotted fevers described here, R. akari is spread through the bite of infected mouse mites (Liponyssoides sanguineus). Cases occur occasionally throughout the United States, and are most often reported out of the northeastern United States, particularly New York City.

The first sign of many spotted fevers (including Rickettsia parkeri rickettsiosis, Pacific Coast tick fever, or rickettsialpox) is generally a dark scab at the site of tick or mite bite, known as an eschar. Eschars usually develop a few days to a week following the bite of an infected tick or mite.

Several days after an eschar develops, patients can develop other signs and symptoms.

Signs and symptoms can include:

• Fever
• Headache
• Rash
• Muscle aches

R. parkeri rickettsiosis, Pacific Coast tick fever, and rickettsialpox are less severe than RMSF; however, it can be difficult to distinguish between RMSF and other spotted fevers, especially during early stages of these diseases. Ticks are typically found in grassy or wooded environments. See your health care provider if you become ill after having been bitten by a tick, or having spent time in areas where ticks may live. Rickettsialpox is spread by mites carried by the common house mouse. Be sure to mention any time spent in areas where mice may be found.

• The signs and symptoms of spotted fevers are similar to those of many other diseases. See your health care provider if you develop the signs or symptoms of spotted fevers.
• Be sure to tell your health care provider if you become ill and have recently been bitten by a tick, exposed to mice, or have spent time in areas where ticks or mice may be found.
• Your health care provider may order certain blood tests to look for evidence of spotted fever infection.
• The results of these tests can take weeks. If your health care provider thinks your illness might be a spotted fever, he or she should recommend antibiotic treatment before results are available.

Some spotted fevers are not life-threatening and can resolve over time, even without treatment. For others, especially RMSF, early treatment with the antibiotic doxycycline can be lifesaving.

Doxycycline is the recommended antibiotic treatment for all spotted fevers, including RMSF in adults and children of all ages.

Prevent spotted fever illness by preventing tick bites, preventing ticks on your pets, and preventing ticks in your yard.

Ticks live in grassy, brushy, or wooded areas, or even on animals, so spending time outside camping, gardening, or hunting will bring you in close contact with ticks. Protect yourself, your family, and your pets. Here’s how:

Before You Go Outdoors

• Know where to expect ticks. Ticks live in grassy, brushy, or wooded areas, or even on animals, so spending time outside camping, gardening, or hunting could bring you in close contact with ticks. Many people get ticks in their own yard or neighborhood.
• Treat clothing and gear with products containing permethrin. Permethrin can be used to treat boots, clothing and camping gear and remain protective through several washings.
• Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus, or 2-undecanone. EPA’s helpful search tool can help you find the product that best suits your needs. Always follow product instructions. Do not use products containing oil of lemon eucalyptus (OLE) or para-menthane-diol (PMD) on children under 3 years old.

After You Come Indoors

Check your clothing for ticks. Ticks may be carried into the house on clothing. Any ticks that are found should be removed. Tumble dry clothes in a dryer on high heat for 10 minutes to kill ticks on dry clothing after you come indoors. If the clothes are damp, additional time may be needed. If the clothes require washing first, hot water is recommended. Cold and medium temperature water will not kill ticks effectively.

Examine gear and pets. Ticks can ride into the home on clothing and pets, then attach to a person later, so carefully examine pets, coats, and daypacks.

Shower soon after being outdoors. Showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease. Showering may help wash off unattached ticks and it is a good opportunity to do a tick check.

Check your body for ticks after being outdoors. Conduct a full body check upon return from potentially tick-infested areas, which even includes your back yard. Use a hand-held or full-length mirror to view all parts of your body. Check these parts of your body and your child’s body for ticks:

• Under the arms
• In and around the ears
• Inside belly button
• Back of the knees
• In and around the hair
• Between the legs
• Around the waist