Louse-borne relapsing fever (LBRF)

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    Last updated: October 2022



    LBRF is caused by Borrelia recurrentis. It occurs in epidemic waves when conditions favourable to the transmission of body lice are met: cold climate/season, overcrowding and very poor sanitation (e.g. refugee camps, prisons). Endemic foci of LBRF are mainly the Sudan and the Horn of Africa (especially Ethiopia). LBRF can be associated with louse-borne typhus (see Eruptive rickettsioses). The mortality rate for untreated LBRF ranges from 15 to 40%.

    Clinical features

    • Relapsing fever is characterized by febrile episodes separated by afebrile periods of approximately 7 days (4 to 14 days).
    • The initial febrile episode lasts up to 6 days:
      • Sudden onset of high fever (axillary temperature > 39 °C), severe headache and asthenia, diffuse pain (muscle, joint, back pain), often associated with gastrointestinal disturbances (anorexia, abdominal pain, vomiting, diarrhoea).
      • Splenomegaly is common; bleeding signs (e.g. petechiae, subconjunctival haemorrhage, epistaxis, bleeding gums), jaundice or neurological symptoms may be observed.
      • The febrile episode terminates in a crisis with an elevation in temperature, heart rate and blood pressure, followed by a fall in temperature and blood pressure, which may last for several hours.
    • Following the initial febrile episode, the cycle usually reccurs; each episode is less severe than the previous one and the patient develops temporary immunity.
    • Complications:
      • collapse during defervescence, myocarditis, cerebral haemorrhage;
      • during pregnancy: abortion, preterm delivery, in utero foetal death, neonatal death.


    In practice, in an applicable epidemiological setting (see above), a suspect case of LBRF is, according to WHO, a patient with high fever and two of the following symptoms: severe joint pain, chills, jaundice or signs of bleeding (nose or other bleeding) or a patient with high fever who is responding poorly to antimalarial drugs. Clothing should be checked for the presence of body lice and nits.


    The diagnosis is confirmed by detection of Borrelia in thick or thin blood films (Giemsa stain). Blood samples must be collected during febrile periods. Spirochetes are not found in the  peripheral blood during afebrile periods. In addition, the number of circulating spirochetes tends to decrease with each febrile episode.


    • Antibiotic treatment (suspect or confirmed cases and close contacts):
      doxycycline PO
      Children: 4 mg/kg (max. 100 mg) single dose 
      Adults: 200 mg single dose
      erythromycin PO
      Children under 5 years: 250 mg single dose
      Children 5 years and over and adults: 500 mg single dose


    azithromycin PO

    Children: 10 mg/kg (max. 500 mg) single dose

    Adults: 500 mg single dose

    • Treatment of pain and fever (paracetamol PO) and prevention or treatment of dehydration in the event of associated diarrhoea.
    • Elimination of body lice is essential in control of epidemics (see Pediculosis, Chapter 4).