In Africa, the animal trypanosomiases kill about 3 million cattle each year with related annual losses in animal productivity of ∼£3 billion. 32 of the 36 affected countries have per capita incomes of less than US$1 per day. The most effective method of combating the trypanosomiases is to eradicate their vectors, the tsetse. Up to the early 1980s, responsibility for vector control in Africa was largely taken by government agencies, using techniques such as large-scale aerial and ground spraying. Following economic crises, structural adjustment and decline or privatisation of veterinary services, much of the onus for controlling tsetse has fallen on livestock keepers themselves (Eisler et al. 2003), but partly as a consequence of trypanosomiasis, many are too poor to afford the cost. Treating cattle with synthetic pyrethroids may provide a way of breaking this cycle of poverty and disease.