Tick-borne relapsing fever (TBRF)


TBRFs are caused by different Borrelia species. They are endemic in temperate and warm regions of the word, especially in Africa (Tanzania, DRC, Senegal, Mauritania, Mali, the Horn of Africa) and mainly in rural areas. TBRF is a major cause of morbidity and mortality in children and pregnant women. The mortality rate for untreated TBRF ranges from 2 to 15%.

Clinical features

The clinical manifestations and complications of TBRF are similar to those of LBRF but neurological symptoms (particularly, cranial nerve palsies and lymphocytic meningitis) are more frequent than in LBRF and the number of relapses is higher.

The clinical diagnosis is difficult, especially during the first episode: cases occur sporadically rather than in outbreaks; the tick bite is painless and usually unnoticed by the patient; symptoms are very similar to those of malaria, typhoid fever, leptospirosis, certain arbovirosis (yellow fever, dengue) or rickettsiosis, and meningitis.

Laboratory

– As for LBRF, the diagnosis is confirmed by detection of Borrelia in the patient’s blood.
– Repeat the examination if the first smear is negative despite strong clinical suspicion.

Treatment

– Antibiotherapy:
doxycycline PO
Children over 8 years: 50 mg 2 times daily or 100 mg once daily for 7 days
Adults (except pregnant or breastfeeding women): 100 mg 2 times daily or 200 mg once daily for 7 days
or
erythromycin PO
Children under 8 years: 25 mg/kg 2 times daily for 7 days
Pregnant or breastfeeding women: 1 g 2 times daily for 7 days

– Treatment of pain and fever (paracetamol PO) and prevention or treatment of dehydration in the event of associated diarrhoea.

 Antibiotic therapy can trigger a Jarisch-Herxheimer reaction with high fever, chills, fall in blood pressure and sometimes shock. It is recommended to monitor the patient for 2 hours after the first dose of antibiotic, for occurrence and management of severe Jarisch-Herxheimer reaction (symptomatic treatment of shock). Jarisch-Herxheimer reaction appears to occur more frequently in LBRF than in TBRF.