[Validity, cost and feasibility of the mAECT and CTC confirmation tests after diagnosis of African of sleeping sickness].

OBJECTIVES

To evaluate the validity, cost and feasibility of two parasitological tests for the confirmation of Human African Trypanosomiasis (HAT): the mini Anion-exchange Centrifugation Technique (mAECT) and Capillary Tube Centrifugation (CTC).

METHODS

During a sleeping sickness screening campaign in 2004 we screened 6502 people in Kwamouth, DRC. Those with a positive result in the Card Agglutination Test for Trypanosomiasis (CATT) had a gland puncture, fresh blood examination, stained thick blood film, mAECT, CTC and CATT titration. Sensitivity and specificity of the confirmation tests were calculated using the combination of all parasitological tests as a reference standard. Each method was costed and its feasibility was assessed with structured interviews of the technicians.

RESULTS

Sensitivity of classical parasitological methods was 44.8% (36.8-53.0), of CTC 56.5% (48.3-64.5) and of mAECT 75.3% (95% CI: 67.7-81.9). Cost per test was 2.82 Euro for mAECT and 0.76 Euro for CTC. Time per test was 29.78 min for mAECT and 18.25 min for CTC. These two tests were judged feasible in field conditions.

CONCLUSION

CTC and mAECT used alone or in combination would bring a considerable improvement to HAT active case finding when used as confirmation tests in CATT-whole blood-positive persons. They proved feasible in operational conditions if a 220 V power supply can be guaranteed. As mAECT is more sensitive but also considerably more expensive, efficiency as well as feasibility considerations will have to guide the choice of the best algorithm.