Comparing apples and oranges - model-based assessment of different tsetse-transmitted trypanosomosis control strategies

The current control strategies for tsetse-transmitted trypanosomosis in cat tle (trypanocidal drugs, tsetse control and trypanotolerant cattle) are bri efly reviewed and their adoption rates in different geographic regions of s ub-saharan Africa are presented. The impact of these control strategies and the potential use of vaccines, should they be developed, on trypanosomosis transmission were compared using a mathematical model. The relative trypan osomosis prevalence compared with no control was estimated across a range o f control coverages (from none to complete control coverage) by varying the change in specific model parameters influenced by individual control measu res. Based on this comparison, the relative rankings of the effect of contr ol strategies on reducing disease prevalence were: vector control, vaccinat ion, and drug use, in that order. In this model, trypanotolerance was assum ed to decrease disease prevalence, but not to influence transmission. Diffe rences in the predicted impact of control measures on the transmission of h uman sleeping sickness are discussed. Finally, the role of transmission mod el outputs as inputs for economic models to guide investment decisions for trypanosomosis control is emphasised. (C) 2001 Australian Society for Paras itology Inc. Published by Elsevier Science Ltd. All rights reserved.