A cheaper tsetse control method |
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Tsetse control through restricted application of insecticide to cattle |
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An improved technique for tsetse fly control is available that even poor producers can afford. The new method, known as restricted insecticide application, relies on the fact that tsetse tend to only bite the legs and stomachs of cattle. Spraying just these areas with an insecticide every two to four weeks kills tsetse fly for a cost of only around 1 British pound per animal per year. There are other benefits too. For example, the technique means that animals still get bitten by ticks when they are young. This allows them to build up an immunity to the diseases carried by ticks. In Uganda, Zambia and Burkina Faso, the technique has already been shown to have reduced the incidence of trypanosomiasis - the devastating disease which tsetse carry. Project Ref: LPP14:
Research Programmes: The research projects that contributed to the development of this output were supported by: DFID's Animal Health (AHP) and Livestock Production (LPP) programmes, FAO, the Zimbabwe Department of Veterinary Services and the Onderstepoort Veterinary Institute (South Africa). Complementary work aimed at controlling West African species of tsetse, initiated independently of the DFID-related projects, was supported by the French government largely through research and development projects associated with the Centre International de Recherche-développement sur l'élevage en zone Subhumide (CIRDES) and the Institut de Recherche pour le Développement (IRD) Relevant Research Projects:
Project Partners:
Tsetse-borne trypanosomiasis is a severe constraint to the livelihoods of poor livestock owners across ~10 million square kilometres of sub-Saharan Africa. Trypanocidal drugs can help but are subject to problems such as widespread resistance, so that the most reliable policy against the disease is vector control. The cheapest method of controlling tsetse is the use of insecticide-treated cattle (ITC). Treating an animal with insecticide does not prevent tsetse from biting it directly but, rather, like other forms of tsetse control, reduces the overall abundance of tsetse and hence disease transmission. To achieve adequate control, a critical density of cattle (ca. 4 treated animals/km2) must be treated over a relatively large area (>100 km2), hence requiring the participation of many livestock keepers. For the poorest livestock keepers however, use of this method is constrained by the relatively high cost of insecticides and the risk that widespread treatment of cattle with insecticide to control tsetse may exacerbate tick-borne diseases (eg, anaplasmosis, babesiosis, cowdriosis)and cause environmental damage, especially through impacts on dung beetles. Means of minimising these problems were suggested by studies in Burkina Faso, South Africa, Tanzania and Zimbabwe, showing that tsetse feed mainly on the legs and belly of older cattle. By treating only those body regions of older animals at 2-4 week intervals, insecticide costs are reduced by 90%, environmental damage is negligible, and young, untreated, cattle are still bitten by ticks,and hence develop a natural, life-long immunity to several tick-borne diseases. The restricted application of insecticide to cattle (RAIC) costs ~£1/animal/year which is comparable to the cost of a single dose of trypanocide. Consequently, even the poorest livestock keepers can afford RAIC and avoid the real costs of living with trypanosomiasis, which are likely to include repeated trypanocidal applications and loss of productivity associated with morbidity. The method has reduced tsetse numbers and the incidence of human and animal trypanosomiasis in Uganda, Zambia and Burkina Faso. The African Union's Pan-African Tsetse and Trypanosomiasis Eradication Programme (PATTEC) has initiated area-wide operations to eliminate tsetse in Angola, Botswana, Burkina Faso, Ethiopia, Ghana, Kenya, Mali, Uganda and Zambia. These operations will use a variety of tsetse control methods including insecticide-treated cattle. The method is also being promoted by local NGOs and government agencies in most tsetse-affected countries, involving smaller-scale operatons to control, rather than eliminate the flies. By adopting the RAIC refinement, the cost-effectiveness of these interventions will improve radically.
The use of RAIC to control tsetse-borne trypanosomiasis will improve the health of livestock, including not only cattle but also pigs, goats, sheep, donkeys, horses and camels. Humans also suffer trypanosomiasis, in the form of sleeping sickness, and for the Rhodesian form of the disease cattle are an important reservoir host. Hence RAIC also improves human health, as demonstrated in Uganda. Improvements in the health and productivity of draught animals - particularly cattle -have indirect benefits for the productivity of mixed crop-livestock systems. In Ethiopia, the absence of draft animals due, for example, to trypanosomiasis leads to delayed planting, lower crop yields and higher production costs. Crops likely to benefit particularly from the improvements in the health and availability of draught animals include maize, cotton and sorghum. Research by AHP-supported projects indicates that this approach could have an impact on malaria in those regions of sub-Saharan Africa where the malaria parasite is transmitted predominantly by Anopheles arabiensis which feeds on humans and cattle. Such areas include the Greater Horn, southern Africa, the Maasai steppe of East Africa and the Sahel.
The two main factors preventing farmers from controlling tsetse effectively are (i) the relatively high cost of current control methods and (ii) inadequate technical understanding and hence poor planning and execution. The present output addresses the first constraint while two others (Tsetse Muse; Tsetse Plan) provide detailed information on the safe and effective use of various methods of tsetse control, including RAIC used alone or with other forms of tsetse control. Experience in Uganda shows that RAIC can reduce significantly the incidence of Rhodesian sleeping sickness. Accordingly, links between this output and 'Diagnostics that can identify human-infective trypanosomes in cattle blood' and 'Treatment of cattle to eliminate the animal reservoir of T. b. rhodesiense' would contribute to the promotion of human health. Trypanosomiasis is only one of several diseases affecting the health and productivity of African livestock, so that interactions between all of the diseases affect their impact and management strategies. For instance, on the one hand animals affected by trypanosomiasis are more susceptible to tick-borne diseases while on the other the treatment of cattle with insecticide impacts on both ticks and tsetse. For livestock keepers in sub-Saharan Africa, the management of tsetse and trypanosomiasis forms only part of a wider livestock strategy and the prompt and accurate diagnosis of animal diseases is crucial for cost-effective management. Accordingly, there are synergistic links with the AHP output 'Simple decision tools for diagnosis of endemic diseases in Africa' which includes tools to improve the diagnosis and management of trypanosomiasis and other vector-borne diseases. Since livestock are an integral part of mixed farming systems in sub-Saharan Africa the improved health and productivity of humans and livestock enhances crop production. Accordingly, this output has links to the CPP output concerned with 'Draught animal power' and the LPP's 'Draught animal toolbox'. How the outputs were validated:
Where the Outputs were Validated:
Who are the Users? In Uganda, a public-private partnership between the Ministry of Agriculture, Animal Industries and Fisheries (MAAIF), the Coordinating Office for Control of Tsetse and Trypanosomiasis (COCTU), Makerere University, veterinary and pharmaceutical companies (CEVA; Coopers) and local livestock owners will treat ~200,000 cattle with a combination of trypanocides followed by monthly treatment with deltamethrin using RAIC. The intervention aims to alleviate human and animal trypanosomiasis and halt the northward expansion of Rhodesian sleeping sickness. In West Africa, various French-supported development projects are promoting the use of RAIC. In Burkina Faso, the ARIOPE (Appui au Renforcement Institutionnel des Organisations Professionnelles d'Eleveurs Modernes) project has constructed ~20 footbaths for use by peri-urban dairy producers while the PAEOB project (Projet d'aide à l'Elevage dans l'Ouest du Burkina) aims to promote the technique among traditional Burkinabe livestock keepers. Other French-supported projects in the region, including the WECARD (West and Central African Council for Agricultural Research and Development) programme in Benin and Mali and the ARDESAC (Appui à la Recherche Régionale pour le développement durable des Savanes d'Afrique Centrale) project working in Cameroon, the Central African Republic and Chad also plan to construct footbaths to promote RAIC. While the current use of the RAIC is limited, there is widespread use of the standard whole-body method. For instance, Appropriate Applications Ltd (UK) has recently supplied 1500 L of deltamethrin 1% pour-on to Uganda and 8200 L to Ethiopia. This total (9700 L) is sufficient to treat ~32,000 adult cattle for a year using the standard method compared to >150,000 cattle using RAIC. Where the outputs have been used: The RAIC method is being used by cattle owners in the Apac, Lira and Kabamaido districts of Uganda and peri-urban dairy farmers in the vicinity of Bobo-Dioulasso, Burkina Faso. The whole-body method is being used in all tsetse-affected countries for the control of tick- and/or tsetse-borne diseases. Specific examples of areas where this method is being used on a large scale to control tsetse include southern Ethiopia and northern Zimbabwe. Ethiopia has recently imported 8200 L of deltamethrin pour-on to treat cattle. The cost-effectiveness of this operation would be improved if the whole body method were replaced by RAIC. In Zimbabwe, the Department of Veterinary Services is currently treating ca. 95,000 cattle to control trypanosomiasis in north Mashonaland and the costs of this programme could be reduced enormously if RAIC was adopted. Scale of Current Use: In Uganda, the initial trial of RAIC was conducted in 2005 and involved the treatment of ca. 1000 cattle from 12 villages. A large-scale tsetse and trypanosomiasis control operation was initiated in September 2006 and this will involve the treatment of ca. 200,000 cattle from three districts where ca. 2 million people live. In Burkina Faso, the initial trial of RAIC was performed in 2003 and involved the treatment of ca. 80 cattle. Currently, ca. 60 peri-urban dairy producers are regularly treating ~2500 cattle in the vicinity of Bobo-Dioulasso. The use of the technique is expected to expand in both countries, since each has major tsetse control operations planned as part of the PATTEC initiative. These operations, supported by loans from the African Development Bank, aim to eliminate tsetse from 15,000 km2 of Uganda and 40,000 km2 of Burkina Faso and are expected to rely heavily on insecticide-treated cattle. Policy and Institutional Structures, and Key Components for Success: The use of RAIC has not reached its full potential, either as a replacement for the standard (whole body) treatment that has been used for ca. 20 years, or as a new method for extending tsetse control into areas where control was formerly too costly. However, we can draw several lessons from the uptake of the standard treatment.
Direct and Indirect Environmental Benefits: All tsetse control methods have two potential types of impact on the environment. One relates to the direct impact of the technique and the other concerns the consequences of improving the health and productivity of livestock. The RAIC method developed, in part, as a consequence of concerns regarding the environmental impact of the standard (whole body) method of treating cattle with insecticide. The RAIC system reduces the amount of insecticide used and hence the impact on non-target organisms. Moreover, since the method does not require plunge dips, the environmental and health hazards associated with their use are avoided. With effective land-use planning and implementation, the use of insecticide-treated cattle to control tsetse can alleviate environmental degradation associated with the concentration of people and livestock into areas naturally free of tsetse. Adverse Environmental Impacts: The method does not have any significant direct impact on the environment. However, without effective land-use planning and implementation, the use of insecticide-treated cattle to control tsetse could lead to environmental-degradation arising from inappropriate land-use. Coping with the Effects of Climate Change, or Risk from Natural Disasters: Predictive models of climate change suggest that there will be shifts in the areas suitable for pastoral and mixed system and in the distribution of tsetse (ILRI, 2000; Thornton et al., 2006). For the morsitans group of tsetse, which includes the major vectors of animal trypanosomiasis, there will be a decrease in suitable habitat along the northern margin of the west African belt and over a large area of southern Sudan and southern Zambia, and an increase along the southern edge of the west African belt and scattered parts of Kenya, Uganda and Ethiopia. RAIC can play an important role in controlling tsetse in current and predicted areas of infestation. More generally, livestock are important in reducing vulnerability to natural and man-made disasters (see under "How the Poor have Benefited"). The use of insecticide-treated cattle, including RAIC, is particularly useful in this role since the treatment is applied to cattle whereas other methods of control (eg, aerial and ground spraying) are geographically fixed. Hence, livestock keepers fleeing, say, a war zone can move with their treated cattle and expect to achieve some measure of control. By contrast, if the area had been controlled by, say, aerial spraying the benefits would be lost. References Barrett, J.C. (1992) The economic role of cattle in communal farming systems in Zimbabwe. Network Paper 32b. Overseas Development Insitute, London, UK Barrett, J.C. (1997) Economic Issues in Typanosomiasis Control Bulletin 85. Natural Resources Institute, Chatham Maritime. Bauer, B. et al. (1999). Improvement of cattle productivity through rapid alleviation of African animal trypanosomiasis by integrated disease management practices in the agropastoral zone of Yale, Burkina Faso. Tropical Animal Health and Production 31, 89-102. Baylis, M. & Stevenson, P. (1998) Trypanosomiasis and tsetse control with insecticidal pour-ons - fact and fiction?. Parasitology Today 14, 77-82. Bourn et al. (2005) Cheap and safe tsetse control for livestock production and mixed farming in Africa. Aspects of Applied Biology 75, Bouyer, J. et al. (2006a) Tsetse control in cattle from pyrethroid footbaths. Preventative Veterinary Medicine (in press). Brownlow et al. (2006) Improving cattle health in rural Uganda: novel and existing treatment options available to livestock keepers. Poster presented at International Congress of Parasitology (ICOPA XI), Glasgow, Scotland. Doran, M. (2000) Socio-economics of trypanosomosis. Implications for control strategies within the Common Fly-Belt of Malawi, Mozambique, Zambia and Zimbabwe. Bovine trypanosomosis in Southern Africa, Vol. 3. Harare, Zimbabwe, Regional tsetse and trypanosomiasis control project for Southern Africa. 156 pp. Fox, R.G.R. et al. (1993) Effect on herd health and productivity of controlling tsetse and trypanosomiasis by applying deltamethrin to cattle. Tropical Animal Health Production 25, 203-214. Hargrove, J. W. et al.(2000) Insecticide-treated cattle for tsetse control: the power and the problems. Medical and Veterinary Entomology 14, 123-130. LID (Livestock in Development). 1999. Livestock in poverty focused development. Livestock in Development, Crewkerne, UK. Shaw et al. (2006) Mapping the benefits: a new decision tool for tsetse and trypanosomiasis interventions. Research Report. Department for International Development, Animal Health Programme, Centre for Tropical Veterinary Medicine, University of Edinburgh, UK and Programme Against African Trypanosomiasis, Food and Agriculture Organization of the United Nations, Rome, Italy. Shaw, A.P.M. (2004) Economics of African Trypanosomiasis. In The Trypanosomiases (ed. by I. Maudlin et al.). pp. 369-402, CABI Wallingford Stachurski, F. et al. (2006b) La lutte contre les ectoparasites des bovins par pédiluve : une méthode innovante utilisée en zone péri-urbaine sub-humide du Burkina Faso. Revue d'Elevage et de Médicine Vétérinaire des Pays Tropicaux 58, 221-228. Swallow, B.M. (2000) Impacts of Trypanosomiasis on African Agriculture. PAAT Technical and Scientific Series 2, FAO, Tome, 52 pp. Thornton et al. (2002) Mapping poverty and livestock in developing countries. International Livestock Research Institute (ILRI) Nairobi, Kenya, 132 pp. Thornton et al., (2006) Cattle trypanosomiasis in Africa to 2030. Website: Torr et al., (2006b) Less is more: the restricted application of insecticide to cattle to improve the cost and efficacy of tsetse control. Medical & Veterinary Entomology (in press). Torr, S. J. & Mangwiro, T.N.C (2000) Interactions between cattle and biting flies: effects on the feeding rate of tsetse. Medical and Veterinary Entomology 14, 400-409 Torr, S. J. et al.(2001). Application of DNA markers to identify the individual-specific hosts of tsetse feeding on cattle. Medical and Veterinary Entomology 15, 78-86. Torr, S.J. et al. (2006a) The effects of host physiology on the attraction of tsetse (Diptera: Glossinidae) and Stomoxys (Diptera: Muscidae) to cattle. Bulletin of Entomological Research 96, 71-84. Vale G A. et al. 1999. Insecticide-treated cattle for controlling tsetse (Diptera: Glossinidae): some questions answered, many posed. Bulletin of Entomological Research 89, 567-577. Vale, G.A. & Grant, I.F. (2001). Modelled impact of insecticide-contaminated dung on the abundance and distribution of dung fauna. Bulletin of Entomological Research 92, 251-263. Vale, G.A. et al. (2004) Biological and chemical assays of pyrethroids in cattle dung. Bulletin of Entomological Research 94, 273-282. Relevant Research Projects,
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