Typhus is caused by one of two types of bacteria: Rickettsia typhi or Rickettsia prowazekii. The form of typus depends on which type of bacteria causes the infection.
Rickettsia typhi causes murine or endemic typhus. Endemic typhus is uncommon in the United States. It is usually seen in areas where hygiene is poor and the temperature is cold. Endemic typhus is sometimes called "jail fever."
Murine typhus occurs in the southeastern and southern United States, often during the summer and fall. It is rarely deadly. Risk factors for murine typhus include:
Exposure to rat fleas or rat feces
Exposure to other animals (such as cats, opossums, raccoons, skunks, and rats)
Rickettsia prowazekii causes epidemic typhus and Brill-Zinsser disease. Brill-Zinsser disease is a mild form of epidemic typhus. It occurs when the disease re-activates in a person who was previously infected. It is more common in the elderly. Lice and fleas of flying squirrels spread the bacteria.
Symptoms of murine or endemic typhus may include:
Dull red rash that begins on the middle of the body and spreads
Extremely high fever (105 - 106 degrees Fahrenheit), which may last up to 2 weeks
The early rash is a light rose color and fades when you press on it. Later, the rash becomes dull and red and does not fade. People with severe typhus may also develop small areas of bleeding into the skin (petechiae).
Signs and tests
A complete blood count (CBC) may show anemia and low platelets. Other blood tests for typhus may show:
Call your health care provider if you develop symptoms of typhus. This serious disorder can require emergency care.
Avoid areas where you might encounter rat fleas or lice. Good sanitation and public health measures reduce the rat population.
Measures to get rid of lice when an infection has been found include:
Boiling clothes or avoiding infested clothing for at least 5 days (lice will die without feeding on blood)
Using insecticides (10% DDT, 1% malathion, or 1% permethrin)
Bechah Y, Capo C, Mege JL, Raoult D. Epidemic typhus. Lancet Infect Dis. 2008;8:417-426.
A.D.A.M. Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital (9/15/2010).