Rocky Mountain Spotted Fever and other Spotted
Fever Group Rickettsioses in the United States
FACT SHEET 18-004-0618

Spotted fever group rickettsioses (SFGR) occur world-wide and impact animal and human health. In the United States, there
are three common tick-borne SFGR: Rocky Mountain spotted fever (RMSF), Tidewater spotted fever, and Pacific coast tickfever. RMSF is the most commonly reported SFGR in the U.S., and is caused by the bacterial organism Rickettsia rickettsii.
Rickettsia parkeri causes Tidewater spotted fever, while Rickettsia philipii causes Pacific coast tick fever.
How does a person get a spotted fever group rickettsiosis (SFGR) disease?
You can get RMSF or another SFGR if you are bitten by a tick infected with Rickettsia
rickettsii or another pathogenic Rickettsia. Bacteria in the tick’s saliva are transmitted to
you while the tick is feeding. An infected tick must be attached to you for several hours
for disease transmission to take place.
Dermacentor variabilis (American dog

Do all ticks transmit these diseases?
tick) female (left) and male (right)
No, only certain species of ticks are capable of transmitting Rickettsia. There are four
primary vectors (transmitters) of RMSF in the U.S.: the American dog tick (Dermacentorvariabilis), the Rocky Mountain wood tick (Dermacentor andersoni), the Pacific coast tick(Dermacentor occidentalis), and the brown dog tick (Rhipicephalus sanguineus). The
American dog tick is responsible for transmitting the majority of RMSF cases. This tick is
widely distributed throughout the Eastern U.S., and in limited areas along the Pacific
Coast. The Rocky Mountain wood tick and the Pacific coast tick are only found in theRhipicephalus sanguineus (brown dog
Western U.S. The brown dog tick is distributed globally, and has been associated withtick) female (left) and male (right)
outbreaks of RMSF in Arizona and Mexico. The Gulf Coast tick (Amblyommamaculatum) is primary vector of the agent of Tidewater spotted fever, and is distributed
throughout the southeastern and Mid-Atlantic U.S. The Pacific coast tick can also transmit Pacific coast tick fever.
How common are these diseases?
According to the Centers for Disease Control and Prevention (CDC), the number of cases of SFGR reported to the CDC peryear increased annually from 424 cases in 1993, to 4470 cases reported in 2012. Although RMSF was first recognized in1896 in Idaho, and was a serious illness in the Rocky Mountain states in the early 1900s, it soon became apparent that
RMSF is widely distributed throughout most of the U.S. The majority of cases occur in the southeastern and south centralstates today. North Carolina and Oklahoma report the highest incidences of RMSF. Rickettsia rickettsii only exists in thewestern hemisphere, and outside of the U.S., RMSF has been documented in southern Canada, Central America, Mexico,and parts of South America. However, there are other tick-borne SFGR that cause can cause human illness worldwide.
Tidewater spotted fever and Pacific coast tick fever are relatively new Rickettsia, and are underreported. Evidence suggests
they are often confused with RMSF.
How serious are these diseases?
Prior to discovering tetracycline and chloramphenicol antibiotics in the late 1940s, 20-80% of people infected with R. rickettsii
died. Today, despite advances in medical care and effective drug treatments, the disease still has a fatality rate of 5% to10%, making RMSF the most lethal tick-borne disease in the U.S. The majority of patients with RMSF must be hospitalized.
There are no known fatalities attributed to infection with R. parkeri or R. philipii, which have milder symptoms than true
RMSF.
What are the symptoms of Rocky Mountain spotted fever?
Symptoms usually appear 3-12 days after a tick bite, and rapidly worsen. Initial symptoms can include moderate-to-highfever, severe headache, nausea, vomiting, muscle pain, chills, and extreme exhaustion. In 2 to 4 days after the onset offever, a red-spotted rash often appears, starting on the extremities (wrists, forearms, ankles, soles and palms), and thenquickly spreading to cover much of the body, including the face. Abdominal pain, diarrhea, and joint pain may also develop.
RMSF can be confused with other illnesses, and proper diagnosis may be delayed if the rash is absent, slow to develop, ordoes not appear.

Army Public Health Center, Entomological Sciences Program
8252 Blackhawk Road, APG, MD 21010-5403
COM 410-436-3613 / DSN 312-584-3613 / Website: http://phc.amedd.army.mil
Approved for Public Release, Distribution Unlimited

How is Rocky Mountain spotted fever diagnosed?
The signs and symptoms of RMSF are similar to those of many other diseases. See your health care provider if you develop
any of the signs or symptoms of RMSF. Be sure to tell your health care provider if you become ill and have recently been
bitten by a tick or have spent time in areas where ticks may be found. Your health care provider may order certain blood
tests to look for evidence of RMSF.
What can I do to reduce my risk of becoming infected with RMSF?
There is no vaccine to protect against RMSF. Therefore, you can help prevent RMSF
and other tick-borne diseases by protecting yourself from ticks. Using the DoD Insect
Repellent System provides the best protection from ticks when in tick habitat (tallgrass, weeds, scrubby areas, woods and leaf litter). It incorporates permethrin
repellent on the uniform; DEET, picaridin or IR3535® repellent on exposed skin; aproperly worn uniform; and sleeping inside a permethrin-treated bed net.
How do I know if my uniform is treated with permethrin repellent?
Factory-treated permethrin Army Combat Uniforms (ACU) and Occupational
Using all elements of the DoD Insect
Camouflage Pattern (OCP) uniforms are now available to all Soldiers. The ACU/OCP
Repellent System provides maximum andtrouser and coat will have a sewn-in label indicating the uniform is factory-treated withsafe protection from vector-borne
permethrin. Untreated ACUs can be permanently treated with the IDA kit (NSN 6840diseases. Diagram: VID, APHC01-345-0237), which can last up to 50 washings, or temporarily treated using the0.5% aerosol spray can (NSN 6840-01-278-1336), which can be reapplied after 6weeks and the sixth washing. Never retreat uniforms that have been factory-treated, treated with an IDA kit, or treated using
a 2-gallon sprayer. Always read and follow the label directions when applying permethrin. Permanently mark the uniform
label with the permethrin treatment date. NEVER APPLY PERMETHRIN TO THE SKIN! Civilians can purchasecommercially available 0.5% permethrin aerosol products and permethrin factory-treated clothing.
What standard military insect repellent products are available for exposed skin?
Approved military insect repellents for use on exposed skin come in a variety offormulations. Always refer to the label to determine frequency of repellent
application based on activity. Do not apply repellent to eyes, lips, or tosensitive or damaged skin. Available military repellents are:• Cutter® pump spray (NSN 6840-01-584-8598) contains 25% DEET; one
application protects for up to 10 hours.
• Bullseye™ Bug Repellant pump spray (NSN 6840-01-656-7707)
contains 20% IR3535®; provides protection for up to 8 hours.
• Natrapel® pump spray (NSN 6840-01-619-4795) contains 20%picaridin; one application protects for up to 8 hours.
• Ultra 30™ Insect Repellent Lotion (NSN 6840-01-584-8393) contains 30% Lipo DEET;
one application protects up to 12 hours.
• Ultrathon™ (NSN 6840-01-284-3982) contains 34% controlled-release DEET lotion;
one application protects for up to 12 hours.
• Chigg-Away® lotion (NSN 6840-01-137-8456), contains 10% precipitated sulfur and 5%
benzocaine, repels chiggers.
What is considered a “properly worn” combat uniform?
Military combat uniforms act as a physical barrier against insects, ticks and other diseasetransmitters and biting nuisance pests when worn properly. Wear uniforms with the sleevesrolled down and tuck pants into boots and undershirt into pants. A permethrin-treated uniform
does not provide protection to exposed skin; protect exposed skin with an approved insect
repellent.

Ticks should be removed assoon as possible to prevent
disease transmission. Toeffectively remove a tick, use
pointed tweezers to grab thetick close to skin, and pull thetick out with a slow, steadymotion.

What do I do if a tick is biting me?
Reduce exposure to tick-borne diseases by promptly removing ticks. Unattached ticks do notpresent a threat by crawling on you. See the picture to the right about effectively removing anembedded tick from your skin. For more information on tick removal, viewhttps://www.youtube.com/watch?v=3bl37ceSZ_s, and http://www.tickencounter.org/. Ticks removed from military personnel,their dependents, or DOD Civilians can be submitted for identification and disease testing through the APHC’s DoD HumanTick Test Kit Program: http://phc.amedd.army.mil/topics/envirohealth/epm/Pages/HumanTickTestKitProgram.aspx
Reference: U.S. Centers for Disease Control and Prevention: https://cdc.gov/RMSF
Use of trademarked name does not imply endorsement by the U.S. Army but is intended only to assist in identification of a specific product.
For more information please consult the APHC website - http://phc.amedd.army.mil