Trypanosomiasis (Sleeping sickness)

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Introduction

  • African trypanosomiasis is an acute or chronic disease caused by Trypanosoma brucei namely T. brucei rhodesiense (East Africa) T. brucei gambiense (West Africa)
  • The disease is transmitted to humans by the bites of  infected tsetse fly (Glossina genus)

Clinical features

Early stage:

  • A nodule or chancre following a bite
  • Fever
  • Headache
  • Dizziness
  • Weakness
  • Significant posterior cervical (Winterbottom sign) and supraclavicular lymphadenopathy Splenomegaly

CNS stage:

  • Occurs six months to several years later
  • Characterized by behavioural changes with hallucinations, delusions, and disturbances of sleep with drowsiness during the day and terminating with stupor

Investigations

  • Peripheral blood film for the detection of trypanosomes
  • Rapid Card Agglutination Trypanosomiasis Test (CATT) for antibody detection

Diagnosis

Presumptive

  • Based on the clinical suspicion and history of exposure to the tsetse fly

A finding of the trypanosome in peripheral blood, lymph node aspirate or CSF is confirmatory

Differential diagnoses

  • Malaria fever
  • Meningitis
  • Viral infections involving the CNS

Drug treatment

Early stage

  • Suramin (treatment of b. rhodesiense)
    • Adult and child: 5 mg/kg on day 1, 10 mg/kg on day 3, and 20 mg/kg on days 5, 11, 17, 23 and 30

Or

  • Pentamidine (treatment of b. gambiense)
    • Dose: 4 mg/kg/day IM or IV (diluted in saline in 2-hour infusions) x 7 days

Late stage

  • Melarsoprol (treatment of both gambiense and rhodesiense infections)
    • Adult: 0 - 3.6 mg/kg intravenously in 3 divided doses for 3 days, followed 1 week later with 3.6 mg/kg intravenously in 3 divided doses for 3 days 10 - 21 days later: 3.6 mg/kg intravenously in 3 divided doses for 3 days.

Or

  • Nifurtimox-eflornithine combination therapy (NECT)- (treatment of b. gambiense)
  • Nifurtimox 15 mg/kg per day orally in three doses x 10 days, and eflornithine 400 mg/kg/day IV in two 2-hour infusions (each dose diluted in 250 mL of water for injection) x 7
  • Eflornithine in children weighing <10 kg: dilute in 50 mL of water for injection. Children weighing 10 - 25 kg: dilute in 100 mL of water for injection

Caution/ Follow-up

  • Urine should be examined for casts and protein before and after treatment with suramin
  • Lumbar puncture follow-up for at least 1 year after treatment with melasoprol is required
  • There is no test of cure for African trypanosomiasis
  • After treatment, patients should be closely followed for 24 months and monitored for relapse
  • Recurrence of symptoms will require examination of body fluids, including CSF, to detect the presence of trypanosomes

Prevention

  • Surveillance and treatment
  • Chemoprophylaxis
  • Vector control by selective clearing of vegetation and use of insecticides