[The efficiency of different detection strategies of human African trypanosomiasis by T. b. gambiense]

Abstract

Introduction: Population screening for human African trypanosomiasis (HAT) is often based on a combination of two screening tests: lymph node palpation (LN) and card agglutination test for trypanosomiasis (CATT). This decision analysis compared the efficiency of three alternative detection strategies: screening by LN only, CATT only and their combination (LN and CATT).

Method: An HAT detection strategy was defined as the sequence of screening and confirmation. Efficacy was evaluated in terms of lives saved. The cost of screening and confirmation tests was estimated in US$. The different parameters in the decision tree were based on published literature and observations of the HAT control programme in the Democratic Republic of Congo. A sensitivity analysis was carried out on those parameters subject to uncertainty.

Results: The cost-effectiveness of a detection strategy based on CATT was US $125 per life saved, compared with US $517 for LN and US $452 for the combined. Marginal cost to add LN to CATT only was between US $1225 and US $5000 per life saved. Sensitivity analysis shows that these results are robust to variation.

Discussion: The CATT strategy was the most efficient. None of the strategies was able to avoid more than 60% of HAT deaths. This moderate efficacy is due to the low sensitivity of the confirmatory (diagnostic) tests. Substantial efficiency gains can be obtained by adopting a CATT only strategy and resources can be better allocated to more sensitive confirmatory tests or to increasing the coverage of populations at risk.