Institute Of Recherche En Elevage Pour Le Developpement Ired

N'Djamena, Chad

Institute Of Recherche En Elevage Pour Le Developpement Ired

N'Djamena, Chad
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Mahamat M.H.,Institute Of Recherche En Elevage Pour Le Developpement Ired | Peka M.,Programme National de Lutte contre la Trypanosomiase Humaine PNLTHA | Rayaisse J.-B.,CIRDES Center International Of Recherche Développement Sur L'elevage En Zone Sub Humide | Rock K.S.,University of Warwick | And 11 more authors.
PLoS Neglected Tropical Diseases | Year: 2017

Background: Gambian sleeping sickness or HAT (human African trypanosomiasis) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by riverine species of tsetse. A global programme aims to eliminate the disease as a public health problem by 2020 and stop transmission by 2030. In the South of Chad, the Mandoul area is a persistent focus of Gambian sleeping sickness where around 100 HAT cases were still diagnosed and treated annually until 2013. Pre-2014, control of HAT relied solely on case detection and treatment, which lead to a gradual decrease in the number of cases of HAT due to annual screening of the population. Methods: Because of the persistence of transmission and detection of new cases, we assessed whether the addition of vector control to case detection and treatment could further reduce transmission and consequently, reduce annual incidence of HAT in Mandoul. In particular, we investigated the impact of deploying ‘tiny targets’ which attract and kill tsetse. Before tsetse control commenced, a census of the human population was conducted and their settlements mapped. A pre-intervention survey of tsetse distribution and abundance was implemented in November 2013 and 2600 targets were deployed in the riverine habitats of tsetse in early 2014, 2015 and 2016. Impact on tsetse and on the incidence of sleeping sickness was assessed through nine tsetse monitoring surveys and four medical surveys of the human population in 2014 and 2015. Mathematical modelling was used to assess the relative impact of tsetse control on incidence compared to active and passive screening. Findings: The census indicated that a population of 38674 inhabitants lived in the vicinity of the Mandoul focus. Within this focus in November 2013, the vector is Glossina fuscipes fuscipes and the mean catch of tsetse from traps was 0.7 flies/trap/day (range, 0–26). The catch of tsetse from 44 sentinel biconical traps declined after target deployment with only five tsetse being caught in nine surveys giving a mean catch of 0.005 tsetse/trap/day. Modelling indicates that 70.4% (95% CI: 51–95%) of the reduction in reported cases between 2013 and 2015 can be attributed to vector control with the rest due to medical intervention. Similarly tiny targets are estimated to have reduced new infections dramatically with 62.8% (95% CI: 59–66%) of the reduction due to tsetse control, and 8.5% (95% 8–9%) to enhanced passive detection. Model predictions anticipate that elimination as a public health problem could be achieved by 2018 in this focus if vector control and screening continue at the present level and, furthermore, there may have been virtually no transmission since 2015. Conclusion: This work shows that tiny targets reduced the numbers of tsetse in this focus in Chad, which may have interrupted transmission and the combination of tsetse control to medical detection and treatment has played a major role in reducing in HAT incidence in 2014 and 2015. © 2017 Mahamat et al.

Ndeledje N.,Institute University des science et Techniques dAbeche | Ndeledje N.,CIRDES Center International Of Recherche Développement Sur L'elevage En Zone Sub Humide | Bouyer J.,Institute Senegalais Of Recherches Agricoles | Bouyer J.,CIRAD - Agricultural Research for Development | And 11 more authors.
PLoS ONE | Year: 2013

Background:In Chad, several species of tsetse flies (Genus: Glossina) transmit African animal trypanosomoses (AAT), which represents a major obstacle to cattle rearing, and sleeping sickness, which impacts public health. After the failure of past interventions to eradicate tsetse, the government of Chad is now looking for other approaches that integrate cost-effective intervention techniques, which can be applied by the stake holders to control tsetse-transmitted trypanosomoses in a sustainable manner. The present study thus attempted to assess the efficacy of restricted application of insecticides to cattle leg extremities using footbaths for controlling Glossina m. submorsitans, G. tachinoides and G. f. fuscipes in southern Chad. Methodology/Principal Findings:Two sites were included, one close to the historical human African trypanosomiasis (HAT) focus of Moundou and the other to the active foci of Bodo and Moissala. At both sites, a treated and an untreated herd were compared. In the treatment sites, cattle were treated on a regular basis using a formulation of deltamethrin 0.005% (67 to 98 cattle were treated in one of the sites and 88 to 102 in the other one). For each herd, tsetse densities were monthly monitored using 7 biconical traps set along the river and beside the cattle pen from February to December 2009. The impact of footbath treatment on tsetse populations was strong (p < 10-3) with a reduction of 80% in total tsetse catches by the end of the 6-month footbath treatment.Conclusions/Significance:The impact of footbath treatment as a vector control tool within an integrated strategy to manage AAT and HAT is discussed in the framework of the "One Health" concept. Like other techniques based on the treatment of cattle, this technology should be used under controlled conditions, in order to avoid the development of insecticide and acaricide resistance in tsetse and tick populations, respectively. © 2013 Ndeledje et al.

Fayiz Abakar M.,Institute Of Recherche En Elevage Pour Le Developpement Ired | Nare N.B.,Institute Of Recherche En Elevage Pour Le Developpement Ired | Schelling E.,Swiss Tropical and Public Health Institute | Hattendorf J.,Swiss Tropical and Public Health Institute | And 2 more authors.
Vector-Borne and Zoonotic Diseases | Year: 2014

The seroprevalence of Rift Valley fever (RVF), brucellosis, and Q fever among domestic ruminants on the southeastern shore of Lake Chad was studied. The study area consisted of two parts, including mainland and islands. On the mainland, the study was conducted in nine randomly selected villages and camps. On the islands, samples were collected from all four available sites. A total of 985 serum samples were collected and 924 were analyzed using enzyme-linked immunosorbent assay (ELISA) for RVF. A total of 561 samples collected from islands were analyzed using ELISA for Q fever and both ELISA and Rose Bengal tests (RBT) for brucellosis. The apparent RVF seroprevalence by species was 37.8% (95% confidence interval [CI] 34.2- 41.3) in cattle, 18.8% (95% CI 12.3-25.2) in goats, and 10.8% (95% CI 3.0-18.5) in sheep. For brucellosis and Q fever, only cattle samples from islands were analyzed. For Q fever, the apparent seroprevalence was 7.8% (95% CI 5.6-10.1). For brucellosis, the RBT showed a prevalence of 5.7% (95% CI 3.8-7.6), and ELISA showed 11.9% (95% CI 9.3-14.6) with a kappa value of 0.53 showing a moderate agreement between the two tests. This study confirms the presence of the three diseases in the study area. More research is required to assess the importance for public health and conservation of the Kouri cattle breed. © Mary Ann Liebert, Inc.

Hassaballah K.,University Of Ndjamena | Zeuh V.,Institute Polytechnique Delevage Of Moussoro | Mopate L.Y.,Institute Of Recherche En Elevage Pour Le Developpement Ired | Sembene M.,Cheikh Anta Diop University
Livestock Research for Rural Development | Year: 2015

The purpose of this study was to characterize the morpho-biometrically local chickens in three ecological areas of Chad as regions of Hadjer-Lamis, Lake Chad and Guéra in the Sahel region and the region of Mayo Kebbi western Sudanian zone. Measurements were carried on 803 adult chickens aged at least six months with 521 females and 282 males. The results show that the average weight of mature chickens was 1.35±0.39 kg (females 1.24±0.32 kg, malmensurations, la conservation de la race, de l'interaction génotype-environnement, races autochtones,es 1.54±0.43 kg), varied from 0.45 to 2.75 kg.. The average body girth was 33.1±5.40 cm, the shank length 13.8±2.10 cm, that of tarsus 10.0±2.10 cm and the central finger of 6.82±1.05 cm. Apart from the shank length that is not discriminating in the three areas, the other parameters show different biometric characteristics: so subjects with large size have been identified around Lake Chad, with small size in the mountainous region of Guéra in center of Chad and those with intermediate size in the region of Mayo-Kebbi West in Sudanian zone. This suggests differences linked with adaptation to the environmental factors and this can make possible to consider possibilities of selection of rustic and more productive or crossed strains adapted to the ecological zones of Chad. © iForest – Biogeosciences and Forestry.

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