Sleeping sickness diagnosis: use of buffy coats improves the sensitivity of the mini anion exchange centrifugation test.
OBJECTIVE
To evaluate a modification of the mini anion exchange centrifugation test (mAECT) for the diagnosis of Trypanosoma brucei (T.b.) gambiense human African trypanosomiasis (HAT). To increase its sensitivity, this test uses 350 microl of buffy coat withdrawn from 5 ml of blood instead of blood.


METHODS
The new protocol was first tested experimentally on serial dilution of trypanosomes and was then further evaluated under field conditions on 57 patients with HAT diagnosed during a medical survey in Guinea.


RESULTS
Experimentally, the use of buffy coats improved mAECT sensitivity at least five fold and enabled to consistently detect parasites in blood at a concentration of 10 trypanosomes/ml. During the field evaluation, more patients tested positive by mAECT-bc (96.5%) than by mAECT-blood (78.9%, chi(2) = 6.93, P = 0.008) and lymph juice examination (77.2%, chi(2) = 7.67, P = 0.005). Furthermore, the number of parasites per collectors was significantly higher (7.2 vs. 2.6, P = 0.001) when buffy coats were used instead of blood.


CONCLUSIONS
The use of the mAECT-bc protocol enabled a significant improvement of HAT parasitological diagnosis in Guinea, without any additional costs. It would deserve to be tested in other T.b. gambiense endemic areas.
Camara
Mamadou
M
Programme National de Lutte contre la Trypanosomose Humaine Africaine, Conakry, Guinée.
Camara
Oumou
O
Ilboudo
Hamidou
H
Sakande
Hassan
H
Kaboré
Jacques
J
N'Dri
Louis
L
Jamonneau
Vincent
V
Bucheton
Bruno
B
D000818:Animals; D002498:Centrifugation / Q000379:methods; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010274:Parasitology / Q000379:methods; D012680:Sensitivity and Specificity; D014347:Trypanosoma brucei gambiense / Q000302:isolation & purification; D014353:Trypanosomiasis, African / Q000175:diagnosis*