African trypanosomes Lesson of Parasitology

African trypanosomes
Alpha University Hargeisa Somaliland

1. African TrypanosomiasisAfrican Trypanosomiasis
(Sleeping Sickness)
ALPHA UNIVERSITY COLLEG ALPHA UNIVERSITY COLLEG
Faculty of health science
Department of Medical Laboratory Technology

2. Definition
Infection with protozoa of the genus
Trypanosoma, which causes a chronic
disease with generalized lymph
adenopathy and often fatal
meningoencephalitis.
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3. Aetiology
Parasite - Trypanosoma brucei ssp
Trypanosoma brucei rhodesiense
Trypanosoma brucei Gambians
Vector - Tse Tse fly
Glossina mortisans (Eastern Africa)
Glossina palpalis (Western Africa)
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4. The Parasite
Polymorphic spindle-shaped
Kinetoplast
Flagella & undulating membrane
Trypomastigote
Epimastigote
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5. Epidemiology
50 million at risk
<20% under surveillance
20,000 new case/year
Devastating epidemics
200 endemic foci
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6. Distribution
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7. The Life CycleThe Life Cycle
Human Tse fly
Trypomastigote Trypomastigote
Stumpy Metacyclic
Intermediate Epimastigote
Slender Trypomastigote
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8. Clinical features.
A papule may develop within a few days to 2
weeks at the site of the tsetse fly bite.
Painful, red, indurated nodules may develop (
trypanosomal chancre)
Resolves spontaneously.
The next phase of illness develops with:
Intermittent fever, headache, rigors.
Enlarged lymph nodes in the posterior cervical
triangle is characteristic of Gambian sleeping
sickness (Winter bottom's sign).
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9. Clinical Features
Primary chancre - resolves 2-3 weeks
Initial symptoms - fever & headaches
Day time sleeping
Tremors & Convulsions
Coma & Death
Enlarged cervical lymph nodes
Winterbottoms sign
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10. Diagnosis
Direct microscopy
Blood.
Lymph node aspirate.
Lumbar puncture.
Serology
Animal inoculation
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11. Chemotherapy
Early stage - most recover
Suramin 1 gr I.V for day 1,3,7,14 and 21
Melasporol (drug of choice for CNS disease) 2-3
MG/KG I.V for 3 days. Repeated at 1 and 2 wk
Pentamidine
Late stage - upto 5% relapse
Only Melasporol
10% encephalitis - 5% fatal
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12. Control and prevention
Destruction of animal reservoir
Vector Control
Diagnosis & treatment
Avoiding endemic areas
Protects against tsetse flies.
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13. Trypanosome Elimination
Antibody mediated
Destruction by Kupffer cells
Splenic macrophages minor role ( malaria)
Uptake - C3b - C3bi - direct
C mediated lysis not important
Trypanosome destroyed within minutes
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