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Epidemic Typhus

(European Typhus; Classic Typhus; Louse-Borne Typhus; Jail Fever)

By

William A. Petri, Jr

, MD, PhD, University of Virginia School of Medicine

Last full review/revision Jul 2020| Content last modified Jul 2020
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Epidemic typhus is caused by Rickettsia prowazekii. Symptoms are prolonged high fever, intractable headache, and a maculopapular rash.

Epidemic typhus is a rickettsial disease.

Humans are the natural reservoir for R. prowazekii, which is prevalent worldwide and transmitted by body lice when louse feces are scratched or rubbed into bite or other wounds (or sometimes the mucous membranes of the eyes or mouth). In the US, humans occasionally contract epidemic typhus after contact with flying squirrels.

Fatalities are rare in children < 10 years, but mortality increases with age and may reach 60% in untreated patients > 50 years.

Symptoms and Signs

After an incubation period of 7 to 14 days, fever, headache, and prostration suddenly occur. Temperature reaches 40° C in several days and remains high, with slight morning remission, for about 2 weeks. Headache is generalized and intense. Small, pink macules, which appear on the 4th to 6th day, rapidly cover the body, usually in the axillae and on the upper trunk and not on the palms, soles, and face. Later, the rash becomes dark and maculopapular. In severe cases, the rash becomes petechial and hemorrhagic.

Splenomegaly sometimes occurs. Hypotension occurs in most seriously ill patients. Vascular collapse, renal insufficiency, encephalitic signs, ecchymosis with gangrene, and pneumonia are poor prognostic signs.

Brill-Zinsser disease, a mild recrudescence of epidemic typhus, can occur years after the initial infection if host defenses falter.

Diagnosis

  • Clinical features

  • Biopsy of rash with fluorescent antibody staining to detect organisms

  • Acute and convalescent serologic testing (serologic testing not useful acutely)

  • Polymerase chain reaction (PCR)

Louse infestation is usually obvious and strongly suggests typhus if history (eg, living in or visiting an endemic area) suggests possible exposure.

Treatment

  • Doxycycline

Primary treatment of epidemic typhus is doxycycline 200 mg orally once followed by 100 mg twice a day in adults until the patient improves, has been afebrile for 24 to 48 hours, and has received treatment for at least 7 days.

Chloramphenicol 500 mg orally or IV 4 times a day for 7 days is 2nd-line treatment. Oral chloramphenicol is not available in the US, and its use is associated with adverse hematologic effects, which requires monitoring of blood indices.

Severely ill patients with epidemic typhus may have a marked increase in capillary permeability in later stages; thus, IV fluids should be given cautiously to maintain blood pressure while avoiding worsening pulmonary and cerebral edema.

Prevention

Immunization and louse control are highly effective for prevention. However, vaccines are no longer available. Lice may be eliminated by dusting infested people with malathion or lindane.

Key Points

  • Epidemic typhus is prevalent worldwide; humans are the natural reservoir.

  • Infection is transmitted among humans by body lice when louse feces are scratched or rubbed into louse bites, wounds, or mucous membranes.

  • Small, pink macules rapidly cover the body, later, becoming dark and maculopapular.

  • Mortality increases with age and may reach 60% in untreated patients > 50 years; vascular collapse, renal insufficiency, encephalitic signs, ecchymosis with gangrene, and pneumonia are poor prognostic signs.

  • Suspect epidemic typhus based on clinical manifestations and signs of louse infestation; confirm with fluorescent antibody staining of skin biopsy.

  • Treat with doxycycline or chloramphenicol.

  • Brill-Zinsser disease, a mild recrudescence of epidemic typhus, can occur years after the initial infection if host defenses falter.

Brill-Zinsser Disease

Brill-Zinsser disease is a recrudescence of epidemic typhus, occurring years after an initial attack.

Patients with Brill-Zinsser disease acquired epidemic typhus earlier or lived in an endemic area. Apparently, when host defenses falter, viable organisms retained in the body are activated, causing recurrent typhus; thus, disease is sporadic, occurring at any season or geographic area, and in the absence of infected lice. Lice that feed on patients may acquire and transmit the agent.

Symptoms and signs of Brill-Zinsser disease are almost always mild and resemble those of epidemic typhus, with similar circulatory disturbances and hepatic, renal, and central nervous system changes. The remittent febrile course lasts about 7 to 10 days. The rash is often evanescent or absent. Mortality is nil.

See the Overview of Rickettsial and Related Infections for diagnosis and treatment details.

Drugs Mentioned In This Article

Drug Name Select Trade
No US brand name
PERIOSTAT, VIBRAMYCIN
No US brand names
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NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
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