Summary
Definition
Human African trypanosomiasis (HAT), or sleeping sickness, is a fatal disease caused by extracellular parasites (genus
Trypanosoma
), which are transmitted by tsetse flies (genus
Glossina
).
[Figure caption and citation for the preceding image starts]:
Trypanosoma brucei
species in thick blood smear stained with Giemsa
From the collection of Dr V. Lejon
[Citation ends].
Two morphologically indistinguishable Trypanosoma brucei subspecies cause disease in humans. In west and central sub-Saharan Africa, infection with T b gambiense leads to a chronic disease that may last for years. In east and southern Africa, T b rhodesiense infection causes an acute disease that may be fatal within months. The parasite is initially found in lymph and blood (hemolymphatic stage), but after a variable period, it crosses the blood-brain barrier and invades the CNS (meningoencephalitic stage). [1] [2] [3] [4] [5] [6]
History and exam
Key diagnostic factors
- previous stay in rural west and central Africa (T b gambiense)
- previous stay in game parks in east and southern Africa (T b rhodesiense)
- enlarged cervical lymph nodes/Winterbottom sign (T b gambiense)
- chancre (T b rhodesiense)
- disturbances of consciousness and sleep
Other diagnostic factors
- hx of several treatments against malaria with no improvement
- headache
- fever
- fatigue and general malaise
- women: history of infertility, menstrual disorders, high miscarriage rate
- men: reduced libido, impotence
- pruritus
- edema
- impaired motor functions
- mental changes
- signs of cardiac failure (T b rhodesiense)
- rash
- hepatosplenomegaly
- sensory disorders
Risk factors
- exposure to tsetse fly
- living or working in an area with people infected with Gambiense trypanosomiasis
- living or working in an area with animals infected with Rhodesiense trypanosomiasis
Diagnostic investigations
1st investigations to order
- CBC
- ESR
- serum immunoglobulins
- card agglutination test for trypanosomiasis (CATT)
- rapid diagnostic tests
- immunofluorescence
- ELISA
- chancre aspirate microscopy
- lymph node aspirate microscopy
- blood microscopy
- microhematocrit centrifugation technique
- quantitative buffy coat technique
- mini-anion exchange centrifugation technique (mAECT)
Investigations to consider
- ECG
- CSF WBC count
- CSF microscopy
- double centrifugation of CSF
- modified single centrifugation of CSF
- CSF protein
Emerging tests
- PCR
- intrathecal immunoglobulin production
- stage biomarkers
- immune trypanolysis
- MRI of brain
Treatment algorithm
Contributors
Authors VIEW ALL
Director of Research
Institut de Recherche pour le Développement
Montpellier
France
Disclosures
VL is an author of several references cited in this monograph. VL declares that he has no competing interests.
Medical Officer
Control of Neglected Tropical Diseases
Human African Trypanosomiasis Control Program
World Health Organization
Geneva
Switzerland
Disclosures
JRF is an author of several references cited in this monograph. JRF declares that he has no competing interests.
Former head of WHO HAT control and surveillance programme
WHO temporary advisor
World Health Organization
Geneva
Switzerland
Disclosures
PPS is an author of several references cited in this monograph.
Peer reviewers VIEW ALL
Professor of Molecular Parasitology and Medicine
Centre for Infection
Division of Cellular and Molecular Medicine
St. George's
University of London
London
UK
Disclosures
SK is a consultant for the Foundation for Innovative Diagnostics, a non-profit organization developing diagnostics for neglected diseases such as HAT. SK is an author of a reference cited in this monograph.
Professor
Division of Infection and Immunity
Institute of Biomedical and Life Sciences
The Glasgow Biomedical Research Centre
University of Glasgow
Glasgow
UK
Disclosures
MB declares that he has no competing interests.
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