Modelling appropriate use of trypanocides to restrict wide-spread multi-drug resistance during chemotherapy of animal African trypanosomiasis

Abstract

Trypanocide resistance remains a huge challenge in the management of animal African trypanosomiasis. Paucity of data on the prevalence of multi-drug resistant trypanosomes has greatly hindered optimal veterinary management practices. We use mathematical model predictions to highlight appropriate drug regimens that impede trypanocide resistance development in cattle. We demonstrate that using drugs in decreasing resistance order results in a negligible increase in number of cattle with resistant infection, in contrast to a more pronounced increase from trypanocide use in increasing resistance order. We demonstrate that the lowest levels of trypanocide resistance are achieved with combination therapy. We also show that increasing the number of cattle treated leads to a progressive reduction in the number of cattle with drug resistant infections for treatments of up to 80% of the cattle population for the combination treatment strategy. Our findings provide an initial evidence-based framework on some essential practices that promote optimal use of the handful of trypanocides. We anticipate that our modest forecasts will improve therapeutic outcomes by appropriately informing on the best choice, and combination of drugs that minimize treatment failure rates.

Keywords: Mathematical models; multi-drug resistance; smallholder farmers; trypanocides; trypanosomes.