Relapsing fever is an infection transmitted by a louse or tick. It is characterized by repeated episodes of fever.
Relapsing fever is an infection caused by several species of bacteria in the Borrelia family.
There are 2 major forms of relapsing fever:
Sudden fever occurs within 2 weeks of infection.
In both forms, the fever episode may end in "crisis." This consists of shaking chills, followed by intense sweating, falling body temperature, and low blood pressure. This stage may result in death.
In the United States, TBRF often occurs west of the Mississippi River, particularly in the mountains of the West and the high deserts and plains of the Southwest. In the mountains of California, Utah, Arizona, New Mexico, Colorado, Oregon, and Washington, infections are usually caused by Borrelia hermsii and are often picked up in cabins in forests. The risk may now extend into the southeastern United States.
LBRF is mainly a disease of the developing world. It is currently seen in Ethiopia and Sudan. Famine, war, and the movement of refugee groups often results in LBRF epidemics.
Symptoms of relapsing fever include:
Relapsing fever should be suspected if someone coming from a high-risk area has repeated episodes of fever. This is especially true if the fever is followed by a "crisis" stage, and if the person may have been exposed to lice or soft-bodied ticks.
Tests that may be done include:
Antibiotics are used to treat this condition.
The death rate for untreated LBRF ranges from 10 to 70%. With TBRF, it is 4 to 10%. With early treatment, the death rate is reduced. People with this condition who have developed a coma, heart inflammation, liver problems, or pneumonia are more likely to die.
These complications may occur:
Contact your health care provider right away if you return from a trip and develop a fever. Possible infections need to be investigated in a timely manner.
Wearing clothing that fully covers the arms and legs when you are outdoors can help prevent TBRF infection. Insect repellent such as DEET on the skin and clothing also work. Tick and lice control in high-risk areas is another important public health measure.
Tick-borne relapsing fever; Louse-borne relapsing fever
Horton JM. Relapsing fever caused by Borrelia species. In: Mandell GL, Bennett JE, Dolan R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 242
Petri WA. Relapsing fever and other Borrelia infections. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011: chap 330.
Updated by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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