A variety of Borrelia species may cause relapsing fever. However, unlike the
other spirochetes that cause human disease (the treponemes and leptospires),
they are readily stained by the Giemsa or Wright procedure.2
Tick-borne relapsing fever is the only form of the disease in the United States,
occurring sporadically during the summer in mountainous Western areas. After
a 7-day incubation, illness begins abruptly with high fever, shaking chills, and
severe headache, followed by prostration, myalgias, abdominal pain, vomiting,
High fever (39.4 to 40.6°C) persists for 3 to 6 days, until the characteristic
crisis of defervescence occurs (a sudden fall in temperature accompanied by
drenching sweats). Spirochetes are rapidly cleared from the blood and the
patient remains afebrile until 6 to 10 days later when mutated organisms appear
in the blood in what may be the first of several relapses.2
Of patients with "Borreliosis," 25% to 50% will have visible spirochetes; a
positive finding is highly specific.3
Repeated examinations may be necessary to
demonstrate the organism, which is not seen in the blood during the afebrile
1) Infectious Diseases. (Pocket Picture Guides to Clinical Medicine) WE
Farrar & HP Lambert. Baltimore: Williams & Wilkins (l984). p 52. Illustrated.
The American and African Trypanosomes have a spiral shape and may also
appear on smears (p 70).
(2) "Leptospirosis, relapsing fever, rat-bite fever, and Lyme disease." In:
Scientific American Medicine. E Rubenstein & DD Federman (eds). New York:
Scientific American (2/88). 7:VII:3-5. Illust.
(3) Medical Microbiology and Infectious Diseases. A Braude. Philadelphia:
Saunders (1981). pp 490-5.
(-) Laboratory Diagnosis of Infectious Diseases. A Balows et al. New York:
Springer (1988). pp 105-110.
Zebra Cards: An Aid to Obscure Diagnoses. JG Sotos. Philadephia: American College of Physicians, 1989. ISBN 0-943126-13-4. Copyright © 1989 American College of Physicians. All Rights Reserved. Phone: 1-800-523-1546.