Trypanosomiasis (Sleeping Sickness)

Introduction

Human African trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease. It is caused by infection with protozoan parasites belonging to the genus Trypanosoma.
They are transmitted to humans by tsetse fly (Glossina genus) bites which have acquired their infection from human beings or from animals harbouring human pathogenic parasites.

Clinical features

(Gambian Sleeping Sickness)
Two clinical stages:

  1. Early stage
  2. CNS stage

Early stage:

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

CNS stage:
This occurs six months to several years later and is 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

Treatment

Early stage
Suramin

  • 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

Late stage
Melarsoprol

  • Adult: 2.0 – 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

Caution

  • 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

Prevention

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