The control of tsetse-trypanosomiasis in West Africa, as in other regions of the continent, has historically been in the domain of government investment for the good of the human populations in tsetse-infested areas. The political motivation for government-led campaigns against tsetse flies was considered to be justified in view of the fact that the disease transmitted by tsetse not only affects livestock but also humans. Recent information (Hursey, 2001) suggests that the incidence of African human trypanosomiasis, or sleeping sickness, has been on the rise, with approximately 50 000 deaths recorded in 1998. Approximately 55 million people are considered to be at risk of contracting sleeping sickness (DFID, 2001). The number of people at risk is believed to have risen in some areas of countries experiencing civil unrest (DFID, 2001). With respect to domestic livestock, it is estimated that some 46 million cattle are at risk of contracting African animal trypanosomiasis (AAT) in sub-Saharan Africa (Kristjanson et al., 1999; FAO, 2000). In West Africa, as much as 51, 68 and 90 percent of the regions semi-arid, subhumid and humid zones, respectively, were infested with tsetse in the 1980s (Jahnke, 1982). With the possible exception of Mauritania, all the countries in West Africa are affected with tsetse-transmitted trypanosomiasis to some extent. A recent review of the status of trypanotolerant livestock (Agyemang, 2000a) indicated that most of the countries in West and Central Africa identify tsetse-transmitted trypanosomiasis as a serious health problem to domestic livestock production and agricultural production as a whole.
Several control measures have been in use in many of the countries in the region to reduce the impact of tsetse flies and trypanosomiasis.
Due to limitations of several of these control methods, especially the problem of chemoresistance associated with drug-based control methods, there have been increasing calls for the use of integrated control measures. More recently, in 2000, a call to eradicate tsetse from the African continent was made by heads of states of African countries of the Organization of African Unity, and a new body, the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC), has been set up. Among the primary beneficiaries of the proposed or ongoing tsetse-trypanosomiasis control in much of tsetse-infested West Africa are the agricultural production systems and communities exploiting resources within these systems. The expected spin-off effects (developments) from tsetse-trypanosomiasis control on the socio-economy of the wider rural communities have been a motivation factor in the advocacy of such programmes. Indeed, it is argued that the tsetse-trypanosomiasis problem should be seen in the context of rural poverty and agricultural development because it has direct severe implications on current and future land use and related development (Ilemobade, 2001). It has also been noted that in planning for integrated tsetse and trypanosomiasis control, the exploitation of the innate resistance of trypanotolerant livestock has not been given adequate consideration. It is therefore necessary to define the role of trypanotolerant livestock in the context of integrated control with a view to identifying how and where the use of these animals can contribute more effectively to the control of tsetse flies and trypanosomiasis in West Africa.
Placing the role of trypanotolerant livestock in West Africa in the context of tsetse-trypanosomiasis control would benefit from a brief description of the geopolitical and agricultural economy of the region. Furthermore, in view of the historical ties between West and Central Africa with respect to trade in trypanotolerant livestock, the inclusion of Central Africa in the analyses of the role of trypanotolerant livestock will give a more complete picture of the status of these breeds in the region. Therefore, where relevant, Central Africa is discussed together with West Africa.
The objective of this study is to provide overviews of the current perspectives on the nature of the tsetse-trypanosomiasis problem, various options for controlling the disease complex, the limitations of these control options and possibilities for newer options. This information is then synthesized in such a way as to provide some guiding principles that will facilitate the definition of the role of trypanotolerant livestock in an integrated approach to combat tsetse-trypanosomiasis.
The study aims ultimately to provide a framework that can contribute to the decision-making process of determining where and under what circumstances trypanotolerant livestock might be used economically and sustainably to combat the tsetse-trypanosomiasis problem. The study begins with a general review of the livestock subsector in the subregion and the role of indigenous livestock with particular reference to trypanotolerant livestock (chapter 2). The various options for controlling trypanosomiasis, including the exploitation of the trypanotolerance trait, and their shortcomings are briefly reviewed in chapter 3. Chapter 4 discusses the main factors that are thought to be important now and in the future in defining the relative role of trypanotolerant livestock in the proposed framework. Based on the strength or weakness of the future potential use or current utilization of trypanotolerant livestock in the areas of overlaps or areas of intersects of the factors that were outlined in chapter 4, guidelines to support decisions as to what extent they should be included in an integrated control programme are provided in chapter 5. Discussion and conclusions from the analyses and results are presented in chapter 6.