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Lyme Coinfection Series-Rocky Mountain Spotted Fever

By Beth Aust, RN, Holistic Health Coach

This is a continuation of our Lyme and coinfection series to help educate you.

“Strive not to be a success, but rather to be of value.” — Albert Einstein

Stats & Facts

Rocky Mountain Spotted Fever (RMSF) is caused by the bacterium Rickettsia rickettsii. Rickettsia is a genus of intracellular bacteria that causes the infections RMSF and associated Rickettsial Spotted Fevers. R. rickettsii is the species responsible for RMSF.

Rocky Mountain spotted fever (RMSF) has been a nationally notifiable (reportable to the County Health Department) condition since the 1920s, frequently reported more in men than in women. People over the age of 40 years account for the highest number of reported cases. Surveillance data shows a higher risk for hospitalization in people with compromised immune systems (e.g., resulting from cancer treatments, advanced HIV infection, prior organ transplants, or some medications).

The Centers for Disease Control typically receives somewhere between 300-1200 case reports of RMSF each year, although the number has been increasing in recent years. As with many tick-borne infections, there is a seasonal peak in the late spring and summer months, with May, June, and July accounting for the most cases. More than 90% of cases are reported from April through September.

Humans and pets may contract RMSF. RMSF may be life-threatening, therefore it is important to get early appropriate treatment.

Primary vectors (a vehicle that carries and transmits an infectious pathogen) include the Rocky Mountain Wood Tick, the American Dog Tick, and the Brown Dog Tick. Therefore, the area at risk includes the entire continental United States and Mexico.

Since many patients do NOT recall a tick bite, this CANNOT be a basis for treatment. The classic triad of tick bite/fever/petechial rash is not always reliable to identify at-risk patients early enough.

Symptoms of Rocky Mountain Spotted Fever

Symptoms include fever, headaches, abdominal pain, nausea, vomiting, anorexia, myalgia; characteristic spotted rash* begins on wrists, ankles, palms, and soles, and may be absent early in the disease.


Laboratory findings can include thrombocytopenia (low platelet count), hyponatremia (low sodium), and elevated hepatic transaminases (elevated liver enzymes), but these are frequently not apparent early in the course. Confirmation is by IgG (antibodies) IFA assays (the lab technique used to identify the presence of antibodies) performed on acute and convalescent serum (blood that is collected by an individual who has recovered from an infectious disease that contains antibodies).

In Conclusion:

Rocky Mountain Spotted Fever (RMSF) is a bacterial disease spread through the bite of an infected tick. Most people who get sick with RMSF will have a fever, headache, and rash. RMSF can be deadly if not treated early with the right antibiotic. Doxycycline is the preferred treatment.

Early treatment with antibiotics can prevent severe illness. RMSF can be difficult to diagnose due to the non-specific signs and symptoms in the early stages of illness. Your Providers at IM of CNY are aware that you may not remember a tick bite. Therefore, based on your symptoms, risk factors, exposure, and travel history we will order the proper lab testing to assist in diagnosis.

However, we also will not delay treatment while awaiting test results due to the potential severity of RMSF. RMSF is a nationally notifiable condition in which the County Health Department (the county you live in) is notified of positive results to improve understanding of how common this disease is, where it occurs, and how disease trends change over time.

This blog is part of our Lyme Disease and Coinfection series. Please be sure to check out the other blogs in our series, or subscribe to our newsletter for more information.


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