Relapsing fever (FR) are caused by spirochetes of the genus Borrelia, transmitted to humans by arthropod vectors.
Relapsing fever (FRP):
FRP is caused by Borrelia recurrentis. The disease develops in epidemic when conditions favorable to the spread of body lice are met: cold weather, overcrowding and poor hygiene (eg refugee camps, prisons..). Endemic foci are mainly in Sudan, the Horn of Africa, particularly in Ethiopia. FRP can be associated with epidemic typhus. Without treatment, mortality ranges from 15 to 40%.
Clinical signs :
– The main feature of FR is the succession of febrile episodes separated by afebrile phase of about 7 days (4-14 days).
– The first access takes about 6 days:
• High fever (> 39 ° C) sudden onset, severe headache and fatigue, diffuse pains (myalgia, back pain, arthralgia), often associated with digestive disorders (anorexia, abdominal pain, vomiting, diarrhea).
• An enlarged spleen is common; haemorrhagic signs (p. ex. petechiae, conjunctival injection, epistaxis, gingivorrhagie), jaundice and neurological disorders may be present.
• The febrile episode ends with a “crisis” with the rise in temperature, pulse and blood pressure, followed by defervescence and hypotension may last several hours.
– After the first access, febrile recurrences occur, less severe and short-term immunity develops.
– Complications:
• collapse during defervescence, myocarditis, cerebral hemorrhage;
• during pregnancy: abortion, premature birth, fetal death in utero, neonatal death.
In practice, in a compatible epidemiological context (see above), a suspected case of FRP is, according to the WHO definition, a patient with a high fever associated with two of the following: severe arthralgia, chills, jaundice or signs of bleeding (epistaxis or other) or a patient with a high fever poorly responsive to antimalarial treatment. Clothing should be examined for body lice and nits.
Laboratory:
The diagnosis is confirmed by the detection of Borrelia in the blood smear and thick film (Giemsa staining). The levy must always be performed during febrile periods. Spirochetes are not visible in the peripheral blood during afebrile phases. In addition, the number of circulating spirochetes tends to decrease with each new episode of fever.
Treatment :
– Antibiotic (cases suspected or confirmed and close contacts):
doxycycline PO 1
Children: 100 mg single dose
Adult: 100 or 200 mg single dose
or erythromycin PO
Child </ = 5 years: 250 mg single dose
Children> 5 years and adults: 500 mg single dose
– Treatment for pain and fever (paracetamol PO) and prevention or treatment of dehydration in cases of associated diarrhea.
– Elimination of body lice is critical to controlling the epidemic.
Tick-borne relapsing fever (FRT):
The FRT is due to several other species of Borrelia. They are endemic in warm and temperate regions of the world, particularly in Africa (Tanzania, DRC,
Senegal, Mauritania, Mali, Africa’s Horn) and mainly in rural areas. They represent an important cause of mortality and morbidity in pregnant women and children. Without treatment, mortality ranges from 2 to 15%.
Clinical signs :
Same presentation and complications for FRP but neurological disorders
(Including cranial nerve palsies and lymphocytic meningitis) are more frequent and the number of recurrences is more important than the FRP.
The clinical diagnosis is difficult, especially when you first access: the cases are sporadic; the tick bite is usually painless and goes unnoticed; the symptoms resemble those of malaria, typhoid, leptospirosis, certain arboviruses (yellow fever, dengue) or rickettsial infections and meningitis.
1 * Doxycycline is usually against-indicated in children under 8 years and pregnant women.
However, in the absence of erythromycin, it can be used in the treatment of relapsing fever, administration of a single dose not to provoke any adverse effects.
Laboratory:
– As for the FRP, the diagnosis is based on the detection of Borrelia in the blood.
– If a strong clinical suspicion, repeat exams if the first smear is negative.
Treatment :
– Anti-biotherapy :
doxycycline PO
Children over 8 years: 100 mg / day in 2 divided doses for 5 days
Adults (except pregnant women): 200 mg / day in 2 divided doses for 5 days or erythromycin PO
Children under 8 years: 50 mg / kg / day in 2 divided doses for 5 days
pregnant women: 2 g / day in 2 divided doses for 5 days
– Treatment for pain and fever (paracetamol PO) and prevention or treatment of dehydration in cases of associated diarrhea.
Antibiotic treatment can induce a reaction Jarisch-Herxheimer (high fever, chills, low blood pressure and sometimes shock). It is recommended to keep the patient under observation for 2 hours after the first dose of antibiotic to support a severe reaction (symptomatic treatment of shock). The reaction of Jarisch-Herxheimer seems more common in the FRP in the FRT.
