Rocky Mountain Spotted Fever (RMSF)

Frequently Asked Questions

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Click on a question below to see the answer.

What is Rocky Mountain Spotted Fever?

Rocky Mountain Spotted Fever (RMSF) is a disease caused by the bite of a tick. In Arizona, cases happen more between March and October when ticks are active.

How do you get RMSF?

RMSF is spread through the bite of a tick that has Rocky Mountain Spotted Fever (RMSF). In Arizona, the tick that carries RMSF is the brown dog tick or the Rocky Mountain wood tick in northern Arizona.

What are the symptoms of RMSF?

Symptoms start with a fever and headache. A rash may appear 2-5 days AFTER a fever; however, some cases have a rash and some do not get the rash until late in the disease. Other symptoms include:

  • Nausea
  • Vomiting
  • Abdominal pain
  • Muscle pain
  • Lack of appetite
  • Upper respiratory symptoms

For more information on symptoms of RMSF, go to Clinical Information for Patients.

How soon do symptoms of RMSF appear after a tick bite?

Symptoms usually begin to appear about 7 days after the bite of an infected tick; however, symptoms may appear anywhere between 2 and 14 days.

Find out more information on ticks.

How do I know if I have RMSF?

A doctor should decide if you have RMSF and give you medicine based off of your signs and symptoms. Your doctor may perform blood tests and to decide if you have RMSF. The second blood test tells you if you have RMSF so it is important to go back to the doctor 2 weeks after your first visit.

For more information on diagnosis, go to Clinical Information for Patients.

What is the treatment for RMSF?

Doxycycline is the medicine for adults and children of all ages. Medicine started in the first 5 days has better chance of stopping death from RMSF.

It is important to remember, to take all of your medicine and don’t wait for test results to take the medicine.

For more information on treatment, go to Clinical Information for Patients.

Is a person with RMSF contagious?

No, RMSF is not spread person-to-person.

Can animals get RMSF?

Yes, dogs can get RMSF. Dogs get the disease because the most common tick in Arizona, the brown dog tick, likes to live and feed on dogs. Cats, horses and other species do not get RMSF.

For more information on animals, go to RMSF and Dogs for Pet Owners.

Can dogs give me RMSF?

Dogs may get RMSF; however, they cannot give RMSF to you. However, a dog may bring ticks that have RMSF in or around your home.

Is there a vaccine for RMSF?

No. There is currently no vaccine or recommended prophylaxis (preventative medication) for RMSF.

How can I prevent getting RMSF?

For information on how to remove a tick, go to Prevention.

What should I do if I find a tick attached to me?

For information on how to remove a tick, go to Prevention.