This paper seeks to address the issue of how to integrate economic criteria into the strategic planning process for tsetse and trypanosomiasis control in West Africa. Brent Swallows paper (PAAT, 2000) on the impacts of trypanosomiasis on African agriculture is taken as a starting point. This has provided both an excellent summary and a discussion of the current state of knowledge on the economic impact of trypanosomiasis on livestock and of its wider impacts on agriculture.
First, the methodological issues involved in the economic appraisal of potential projects to control the disease are discussed in some detail here. The various approaches can have profound implications for the type of strategy adopted. This discussion is particularly timely in the light of the current Pan-African initiatives, which reveal a need both for the wider scientific community and for planners to understand the implications for policy- and decision-making of the economic techniques used. One of these is discounting. The literature on the economic appraisal of livestock projects universally advocates putting some value on the use of money over time, reflecting its opportunity cost in terms of resources diverted from other projects and the need to fix some minimum acceptable rate of return on public and private investments. The use of discount rates is thus recommended here, while applying low discount rates in the examples used, so as to lessen the effect of deflating benefits occurring in the distant future as compared to present costs. The terms of reference for this work were to produce economic guidelines for planners in the tsetse and trypanosomiasis field. Accordingly, it is argued that in the current institutional context, each individual project or zone should be the subject of a separate benefit - cost analysis. This ensures that a project is assessed on its own merits, not on its possible technical contribution to a potential continent-wide programme. This again is iv part of sound economic practice and also reflects current policy on dealing with the disease.
The setting out of benefits and costs according to the rules of partial analysis is explained for the case of tsetse and trypanosomiasis control. In particular, it is important to incorporate farmers current strategies for controlling the disease in the economic analysis. Studies have shown that in many areas their use of trypanocides is effective; this means that a proportion of disease losses are already being successfully avoided. The benefits from introducing tsetse control in such situations would not be the elimination of all possible losses due to trypanosomiasis, but would consist of savings in the use of trypanocides plus a further reduction in the losses due to the disease. A dynamic herd model, which includes animal traction among herd outputs, is used to simulate the benefits and costs of tsetse eradication, trypanocide use, and the switch from one to the other. This implies that farmers current strategy of targeting productive animals brings high returns. Enabling farmers to reinforce their efforts by implementing low-cost tsetse control would also bring very high returns. Where technically feasible, area-wide tsetse control or localized eradication becomes more profitable if sufficiently large cattle populations exist to make up the benefit units per km2 and where there is evidence of drug resistance.
Second, from this discussion on methodology, it is argued that there is a need for planners to adopt a standardized and transparent approach for assessing tsetse and trypanosomiasis control schemes. The approach used would itself need to be cost-effective. It would need to use a standard methodology to produce consistently calculated results that could be used for ranking and priority setting. In this context there is an urgent need for updated and fully comparable costings on the various forms of tsetse control. To be of use in project planning, these costings would need to be applicable to West Africa and a standardized approach, which includes overheads, would need to be adopted.
Third, this paper tries to complement the GIS work on the spatial distribution of the factors influencing the economics of v trypanosomiasis in livestock and their expected changes over time. The dynamics of benefits and costs over time are examined, especially in relation to the densities of human and cattle populations. A conceptual model shows tsetse control costs falling with rising human populations. Benefits, however, initially rise and then peak when mixed farming is well established but tsetse challenge persists. Lastly, benefits tend to fall when human populations rise to a level where the flys habitat becomes eroded and/or high cropping intensity means that fewer cattle are kept. This points to the existence of two turning points in the economics of area-wide, long-term tsetse control or elimination: below a certain cattle or human population density there are insufficient benefit units to make it profitable; above a certain human population density fly challenge is reduced, losses due to the disease decline, and cattle numbers may also be lower as the amount of grazing land is reduced. This model is used to characterize situations where controlling the disease may or may not be profitable. These situations and the profitability limits, or turning points identified, coincide to a large extent with those emerging from the GIS priority-setting exercises. The two approaches thus very much complement each other, suggesting that the economic appraisals should focus on those zones that emerge as priority areas from the GIS filtering process. Following this, the tsetse and trypanosomiasis situation in the areas identified can be studied, using sound economic methods to investigate how different interventions can improve on what the farmers are already doing, how they can involve farmers and how they fit into the broad sweep of development in that area.