Suchergebnisse

French Agricultural Research Centre for International Development (CIRAD), Montpellier, France; Insect Pest Control Unit, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Vienna, Austria, Email: J.Bouyer@iaea.org Recently, we hypothesized that shifting the vision of the sterile male from a sexual competitor only to a specific transporter of active biocides to the targeted female might boost the impact of the sterile insect technique (SIT). In the REVOLINC (Revolutionizing Insect Control) project, we are demonstratating this concept using three biocides: Pyriproxifen, Bacillus thuringiensis and a Densovirus against the tiger mosquito (Aedes albopictus). Pyriproxifen is also tested against tsetse (Glossina palpalis gambiensis) and fruit flies (Ceratitis capitata). The technology is presently tested in the laboratory and preliminary results will be presented, as well as a model predicting the relative impacts of SIT and boosted-SIT on the dynamics of the targeted populations. The next steps will be to validate the predictions in operational field trials and compare the evolutionary response of the target populations to these different control pressures (multiple lethal mutations, multiple lethal mutations + biocides, biocides alone), for the three different biocides and three demographic strategies. This will generate breakthrough knowledge on the transmission of biocides and pathogens in insects and the sustainability of genetic control, provide a new control technique for mosquitoes, and improve the cost-effectiveness of SIT in tsetse and fruit flies. We are also addressing technical issues associated to mass-rearing, sterilization, sex separation and aerial release of mosquitoes as well as regulatory issues required for releasing sterile males carrying various biocides. The methodology of the project will be presented, as well as the intermediary results. The REVOLINC project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 682387). (Texte intégral)

L'accroissement de la demande urbaine en protéines animales se traduit, entre autres, par le développement de filières bovines de production laitière dans les zones périurbaines d'Afrique de l'Ouest. Mais la maîtrise imparfaite des maladies et des parasites compromet la croissance de la production. Une technique de lutte innovante, basée sur le passage régulier dans un pédiluve contenant une formulation aqueuse d'un pyréthrinoïde, pourrait pourtant limiter l'impact des tiques et des glossines, principales contraintes pathologiques en zone subhumide. Cette méthode entraîne l'élimination de la plupart des adultes d'Amblyomma variegatum, la tique la plus nocive dans ces régions, avant leur fixation définitive. D'autre part, un tel traitement permet de diminuer fortement la population des glossines riveraines les plus représentées en Afrique occidentale (Glossina tachinoides et G. palpalis gambiensis) et donc de limiter l'incidence des trypanosomoses. Cette méthode assure ainsi une lutte rapide et efficace à coût réduit car la quantité de produit utilisé à chaque passage est faible. Mais la construction de l'installation, qui peut être utilisée par 400 à 600 animaux, représente un investissement non négligeable que des groupements d'éleveurs ou des investisseurs privés peuvent plus facilement prendre en charge que des éleveurs traditionnels isolés. La mise en place de cette méthode peut ainsi être envisagée dans le cadre d'une politique de développement et d'aménagement. L'intérêt et les modalités de l'appui technique nécessaire sont présentés. Au Burkina Faso, un projet d'appui au renforcement des organisations professionnelles d'éleveurs modernes (Ariope) a de la sorte financé quinze installations dans les zones périurbaines de Bobo-Dioulasso et Ouagadougou.

International audience ; In many parts of Africa, tsetse eradication is impossible due to political, environmental or economic circumstances. In these situations, African animal trypanosomosis control relies on communities or farmer-based control, implemented at a local scale in accordance to the eco-epidemiological context and the cattle rearing system to be sustainable. Management of the African animal trypanosomosis requires integrated controls strategies that combine the use of more than one locally-based tool and where possible, needs to be assisted by veterinarians and other animal health professionals. Several tsetse control methods based on insecticide treated cattle (i.e. pour-on, manual spraying, community bath) and insecticide treated target (traps and screens impregnated with insecticides) are available and should be complemented with diagnostic tests and medication (active trypanocides with prophylactic and/or therapeutic action). However, their adoption is mainly dependent on the engagement of communities, farmers and herders. Indeed, the adoption of a locally-adapted control strategy will depend on farmers socio-technical networks, the cost-effectiveness of the control activities, as well as the time and cost for implementation. In general, insecticide treated cattle methods are the most suitable and acceptable for farmers, because they protect a private good i.e. cattle, whereas insecticide treated targets are generally considered to provide a public good. Nonetheless, selection of the most appropriate tools requires consideration of local disease epidemiology (including host-parasite coevolution), local environmental and socioeconomic constraints. The active involvement of communities, farmers and herders is essential from the beginning of the conception of innovative control strategies, and the cost of local integrated pest management should be reduced as much as possible, to be adopted as an acceptable and sustainable animal production cost.

International audience ; In many parts of Africa, tsetse eradication is impossible due to political, environmental or economic circumstances. In these situations, African animal trypanosomosis control relies on communities or farmer-based control, implemented at a local scale in accordance to the eco-epidemiological context and the cattle rearing system to be sustainable. Management of the African animal trypanosomosis requires integrated controls strategies that combine the use of more than one locally-based tool and where possible, needs to be assisted by veterinarians and other animal health professionals. Several tsetse control methods based on insecticide treated cattle (i.e. pour-on, manual spraying, community bath) and insecticide treated target (traps and screens impregnated with insecticides) are available and should be complemented with diagnostic tests and medication (active trypanocides with prophylactic and/or therapeutic action). However, their adoption is mainly dependent on the engagement of communities, farmers and herders. Indeed, the adoption of a locally-adapted control strategy will depend on farmers socio-technical networks, the cost-effectiveness of the control activities, as well as the time and cost for implementation. In general, insecticide treated cattle methods are the most suitable and acceptable for farmers, because they protect a private good i.e. cattle, whereas insecticide treated targets are generally considered to provide a public good. Nonetheless, selection of the most appropriate tools requires consideration of local disease epidemiology (including host-parasite coevolution), local environmental and socioeconomic constraints. The active involvement of communities, farmers and herders is essential from the beginning of the conception of innovative control strategies, and the cost of local integrated pest management should be reduced as much as possible, to be adopted as an acceptable and sustainable animal production cost.

International audience ; In many parts of Africa, tsetse eradication is impossible due to political, environmental or economic circumstances. In these situations, African animal trypanosomosis control relies on communities or farmer-based control, implemented at a local scale in accordance to the eco-epidemiological context and the cattle rearing system to be sustainable. Management of the African animal trypanosomosis requires integrated controls strategies that combine the use of more than one locally-based tool and where possible, needs to be assisted by veterinarians and other animal health professionals. Several tsetse control methods based on insecticide treated cattle (i.e. pour-on, manual spraying, community bath) and insecticide treated target (traps and screens impregnated with insecticides) are available and should be complemented with diagnostic tests and medication (active trypanocides with prophylactic and/or therapeutic action). However, their adoption is mainly dependent on the engagement of communities, farmers and herders. Indeed, the adoption of a locally-adapted control strategy will depend on farmers socio-technical networks, the cost-effectiveness of the control activities, as well as the time and cost for implementation. In general, insecticide treated cattle methods are the most suitable and acceptable for farmers, because they protect a private good i.e. cattle, whereas insecticide treated targets are generally considered to provide a public good. Nonetheless, selection of the most appropriate tools requires consideration of local disease epidemiology (including host-parasite coevolution), local environmental and socioeconomic constraints. The active involvement of communities, farmers and herders is essential from the beginning of the conception of innovative control strategies, and the cost of local integrated pest management should be reduced as much as possible, to be adopted as an acceptable and sustainable animal production cost.

In many parts of Africa, tsetse eradication is impossible due to political, environmental or economic circumstances. In these situations, African animal trypanosomosis control relies on communities or farmer-based control, implemented at a local scale in accordance to the eco- epidemiological context and the cattle rearing system to be sustainable. Management of the African animal trypanosomosis requires integrated controls strategies that combine the use of more than one locally-based tool and where possible, needs to be assisted by veterinarians and other animal health professionals. Several tsetse control methods based on insecticide treated cattle (i.e. pour-on, manual spraying, community bath) and insecticide treated target (traps and screens impregnated with insecticides) are available and should be complemented with diagnostic tests and medication (active trypanocides with prophylactic and/or therapeutic action). However, their adoption is mainly dependent on the engagement of communities, farmers and herders. Indeed, the adoption of a locally-adapted control strategy will depend on farmers socio-technical networks, the cost-effectiveness of the control activities, as well as the time and cost for implementation. In general, insecticide treated cattle methods are the most suitable and acceptable for farmers, because they protect a private good i.e. cattle, whereas insecticide treated targets are generally considered to provide a public good. Nonetheless, selection of the most appropriate tools requires consideration of local disease epidemiology (including host-parasite coevolution), local environmental and socio-economic constraints. The active involvement of communities, farmers and herders is essential from the beginning of the conception of innovative control strategies, and the cost of local integrated pest management should be reduced as much as possible, to be adopted as an acceptable and sustainable animal production cost.

International audience ; In many parts of Africa, tsetse eradication is impossible due to political, environmental or economic circumstances. In these situations, African animal trypanosomosis control relies on communities or farmer-based control, implemented at a local scale in accordance to the eco-epidemiological context and the cattle rearing system to be sustainable. Management of the African animal trypanosomosis requires integrated controls strategies that combine the use of more than one locally-based tool and where possible, needs to be assisted by veterinarians and other animal health professionals. Several tsetse control methods based on insecticide treated cattle (i.e. pour-on, manual spraying, community bath) and insecticide treated target (traps and screens impregnated with insecticides) are available and should be complemented with diagnostic tests and medication (active trypanocides with prophylactic and/or therapeutic action). However, their adoption is mainly dependent on the engagement of communities, farmers and herders. Indeed, the adoption of a locally-adapted control strategy will depend on farmers socio-technical networks, the cost-effectiveness of the control activities, as well as the time and cost for implementation. In general, insecticide treated cattle methods are the most suitable and acceptable for farmers, because they protect a private good i.e. cattle, whereas insecticide treated targets are generally considered to provide a public good. Nonetheless, selection of the most appropriate tools requires consideration of local disease epidemiology (including host-parasite coevolution), local environmental and socioeconomic constraints. The active involvement of communities, farmers and herders is essential from the beginning of the conception of innovative control strategies, and the cost of local integrated pest management should be reduced as much as possible, to be adopted as an acceptable and sustainable animal production cost.

Le suivi de la végétation et l'inventaire de bioindicateurs animaux, micromammifères et insectes, a permis de dresser un bilan des dégradations environnementales dans trois villages situés à proximité de Bobo-Dioulasso. Les dégâts apparemment les plus graves résultent de la coupe des arbres pour le bois de feu et de l'extraction minière du sable et du gravier pour les constructions. Ces activités sont la conséquence du développement urbain. Les dégradations environnementales dues à l'agriculture et à l'élevage paraissent moins importantes. L'ensemble de ces activités humaines fait que les terres maraîchères de Koro sont en train de disparaître, tout comme la forêt classée de Koua. Les suivis et inventaires, réalisés pour mieux cerner cette évolution anthropique de l'environnement, montrent que les espèces animales réagissent à cette forte perturbation du milieu amplifiée par les phénomènes fréquents d'érosion. En conclusion de cette étude, des mesures de protection et de reboisement sont proposées pour limiter l'érosion dans les champs et sur les berges de la rivière. L'extraction minière des matériaux de construction pourrait aussi être organisée pour moins impacter l'environnement ; mais cela risque d'être difficile à mettre en oeuvre car les intérêts individuels priment face aux besoins collectifs.

Une synthèse des connaissances sur l'écologie, l'importance épidémiologique et le contrôle des stomoxes à l'île de la Réunion est présentée. L'intensification de l'élevage bovin dans ce département a créé des conditions optimales pour la pullulation de ces insectes hématophages. Les stomoxes sont non seulement une nuisance directe par la spoliation sanguine et le stress lié au harcèlement des animaux, mais aussi et surtout une nuisance indirecte, en tant que vecteurs mécaniques de nombreuses maladies animales. À la Réunion, le principal rôle pathogène des stomoxes est la transmission de l'anaplasmose bovine, qui est une contrainte sanitaire majeure pour l'élevage de races européennes. Des études récentes ont permis de mieux appréhender leur distribution, leur dynamique et leur structure de populations, mais leur contrôle, organisé par le Groupement de Défense Sanitaire, reste problématique. Les, essais mis en place depuis 1994, ont donné des résultats variables ; les perspectives sont discutées. De nombreuses pistes de recherche sont explorées pour mieux comprendre leur rôle dans la transmission mécanique immédiate ou différée des agents pathogènes. L'amélioration de leur contrôle pourra être assurée en mettant en place une politique de gestion intégrée à l'échelle de l'île, basée sur une meilleure prise en compte des connaissances sur leur écologie et sur l'intégration de nouvelles méthodes de lutte (pédiluves, champignons entomopathogènes, moustiquaires imprégnées).

The riverine tsetse species Glossina palpalis gambiensis Vanderplank 1949 (Diptera: Glossinidae) inhabits riparian forests along river systems in West Africa. The government of Senegal has embarked on a project to eliminate this tsetse species, and African animal trypanosomoses, from the Niayes area using an area-wide integrated pest management approach.A stratified entomological sampling strategy was therefore developed using spatial analytical tools, remote sensing and mathematical modeling. A preliminary phyto-sociological census identified eight types of suitable habitat, which could be discriminated from LandSat 7ETM+ satellite images and denominated wet areas. At the end of March 2009, 683 unbaited Vavoua traps had been deployed, and the observed infested area in the Niayes was 525 km2. In the remaining area, a mathematical model was used to assess the risk that flies were present despite a sequence of zero catches. The analysis showed that this risk was above 0.05 in 19% of this area that will be considered as infested during the control operations. The remote sensing analysis that identified the wet areas allowed a restriction of the area to be surveyed to 4% of the total surface area (7,150 km2), whereas the mathematical model provided an efficient method to improve the accuracy and the robustness of the sampling protocol. The study thus allowed defining the limits of the target population for the eradication campaign. This entomological sampling procedure might be used for other vector or pest control scenarios. (Texte intégral)

Since 2007, the Government of Senegal launched an eradication campaign against the only species present in the Niayes area (Glossina palpalis gambiensis Vanderplank). The fly occupies an isolated pocket of 525km2 but keeps transmitting animal trypanosomoses to livestock with a high incidence, thus hampering the intensification of cattle production systems. An area-wide integrated pest management strategy was selected that targets the entire infested area and combines control methods efficient at high density of the target population (insecticide-treated targets and cattle) with the sterile insect technique (SIT) that shows inverse density dependent properties. The sterile male insects will be released as chilled adults from gyrocopters by air, using a newly developed automatic release machine. One of the principal prerequisites for successful SIT, apart from the availability of sterile males in adequate numbers, is to make sure that the laboratory strain is competitive with the wild males in the target area. This is all the more important as in Senegal, the local target populations are genetically isolated from the G. p. gambiensis populations of the main tsetse belt, and they have a more xerophylous behaviour (the annual rainfall in the Niayes area is below 500mm). The mating compatibility of the strain maintained at the CIRDES, Burkina Faso for more than 40 years (named BKF) with that of the target area in the Niayes was confirmed at the FAO/IAEA Insect Pest Control Laboratory in Seibersdorf, Austria. Thereafter, we released more than 140,000 sterile male flies (BKF) in 4 sites to study their dispersal, survival and competitiveness (recapture rate of 5%). The latter parameter was measured using Fried's index (F), thanks to availability of data on natural abortion rates for more than 3 years in all the release sites before these mark-release-recapture experiments. The BKF strain performed well in 3 out of the 4 sites (daily mortality rates of 15-16%, daily displacement of 420-705m and F of 0.37±0.29), but underperformed in the park of Hann inside Dakar city where pollution is high (mortality rates of 24%, p<0.05). An introgressed strain, constructed using a crossing schedule with BKF female flies and local SEN male flies (5 generations) will be tested soon in this site. Interestingly, the males from the BKF strain performed better in Senegal than in Burkina Faso recently, suggesting some degree of satyrism in this species. (Texte integral)

The riverine tsetse species Glossina palpalis gambiensis Vanderplank 1949 (Diptera: Glossinidae) inhabits riparian forests along river systems in West Africa. The government of Senegal has embarked on a project to eliminate this tsetse species, and African animal trypanosomoses, from the Niayes area using an area-wide integrated pest management approach. A stratified entomological sampling strategy was therefore developed using spatial analytical tools and mathematical modeling. A preliminary phytosociological census identified eight types of suitable habitat, which could be discriminated from LandSat 7 ETM (+) satellite images and denominated wet areas. At the end of March 2009, 683 unbaited Vavoua traps had been deployed, and the observed infested area in the Niayes was 525 km(2). In the remaining area, a mathematical model was used to assess the risk that flies were present despite a sequence of zero catches. The analysis showed that this risk was above 0.05 in 19% of this area that will be considered as infested during the control operations. The remote sensing analysis that identified the wet areas allowed a restriction of the area to be surveyed to 4% of the total surface area (7,150 km(2)), whereas the mathematical model provided an efficient method to improve the accuracy and the robustness of the sampling protocol. The final size of the control area will be decided based on the entomological collection data. This entomological sampling procedure might be used for other vector or pest control scenarios.

Agricultural research for development (AR4D) organizations can achieve greater impact by using complexityaware approaches, but for this to happen a more compelling case needs to be made to justify their use. Our contribution is to develop and test a generalizable complexity-aware theory of change of how AR4D fosters innovation. The proposed model shows that AR4D achieves impact through three interconnected impact pathways: • Technology Development and Adoption Pathway • Capacity Development Pathway • Policy Influence Pathway The paper presents three cases, which provide an empirical test for the model. The cases give good empirical support to the three impact pathways. The theory of change we developed emphasizes self-reinforcing feedback loops as mechanisms by which small, well-focused research interventions can achieve impact at scale. However, to harness complexity in this way requires organizations to make broad-based and profound changes to working practices and the institutions that support them. These include being more circumspect about predictions of program impact at the start, putting in place functional adaptive management systems providing support to reflexive practice and other behaviours known to foster innovation.

Background : In the Niayes area, located in the west of Senegal, only one tsetse species, Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) was present. The Government of Senegal initiated and implemented an elimination programme in this area that included a sterile insect technique (SIT) component. The G. p. gambiensis strain (BKF) mass-reared at the Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES) in Burkina Faso was used for the SIT component. Methodology/principal findings: Studies conducted in 2011 in four localities in the Niayes area (Pout, Sébikotane, Diacksao Peul and the Parc de Hann) showed that the BKF strain demonstrated inferior survival in the ecosystem of the Parc de Hann, a forested area in the city centre of the capital Dakar. Therefore, G. p. gambiensis flies from the Niayes area (SEN strain) were colonized. Here we compared the competitiveness and survival of the two strains (BKF and SEN) in the Parc de Hann. Released sterile males of the SEN colony showed a daily mortality rate of 0.08 (SD 0.08) as compared with 0.14 (SD 0.08) for the BKF flies but the difference was not significant (p-value = 0.14). However, the competitiveness of the SEN males was lower (0.14 (SD 0.10)) as compared with that of the BKF males (0.76 (SD 0.11)) (p-value < 10−3). Conclusions/significance: Based on the results of this study, it can be concluded that the BKF strain will remain the main strain to be used in the elimination programme. Despite the slightly longer survival of the SEN males in the Parc de Hann, the superior competitiveness of the BKF males is deemed more important for the SIT component, as their shorter survival rates can be easily compensated for by more frequent fly releases.

The Government of Senegal has embarked since several years on a project that aims to create a tsetse-free area in the Niayes. The project was implemented using an area-wide integrated pest management (AW-IPM) strategy where the sterile flies used for the sterile insect technique (SIT) component were derived from a colony originating from Burkina Faso. Monitoring the efficacy of the sterile male releases requires the discrimination between wild and sterile males that are sampled in monitoring traps. Before being released, sterile males were marked with a fluorescent dye powder. The marking was however not infallible with some sterile flies only slightly marked or some wild flies contaminated with a few dye particles in the monitoring traps, making it difficult to discriminate between wild and sterile males using a UV camera. We developed a molecular technique based on the cytochrome oxidase gene that efficiently discriminates between wild and sterile males. This tool might be useful for other tsetse control campaigns with a SIT component or for other vector or insect pest control programs.