Etude Phénotypique des Taurins Ndama du Centre de Recherches Zootechniques de Kolda (Sénégal)

Au Sud du Sénégal, du fait de la présence de glossines, le taurin Ndama ou Bos taurus taurus est la principale race bovine élevée par les agropasteurs. L’importance indéniable de ces bovins dans la vie socio-économique a conduit à la création du Centre de Recherches zootechniques de Kolda (CRZ-K) et l’initiation d’un programme de sélection à noyau fermé dès 1972 pour améliorer les performances des taurins. L’actuel noyau de sélection ouvert est constitué par des animaux appartenant au CRZ-K et ceux de la Coopérative des Agro-éleveurs Sélectionneurs de la Ndama (CASE-Ndama). L’objectif de cette étude est de caractériser phénotypiquement les taurins Ndama du noyau de sélection. La collecte des données phénotypiques composées de 15 variables qualitatives et 17 quantitatives a été réalisée sur 118 taurins adultes agés d’au moins quatre ans. L’évaluation des performances pondérales a été réalisée grâce à l’analyse des données longitudinales de 1970 bovins durant la période de 1973 à 2016. Les variables qualitatives ont été exprimées en pourcentages et pour les variables quantitatives, une analyse descriptive et une comparaison des moyennes ont été faites. Les résultats ont montré que la majorité des animaux présentait la même apparence avec une robe fauve uniforme, des cornes bicolores en lyre, des muqueuses peu pigmentées. Avec un dimorphisme marqué chez les bovins, les animaux adultes ont une hauteur au garrot moyenne de 106,9 ± 3,5 cm et un poids moyen de 230,9 ± 40,6 kg. Les moyennes de la longueur du corps et du périmètre thoracique étaient de 112,0 ± 7,9 cm et 150,0 ± 8,4 cm respectivement. Cette étude tout en montrant la hausse des mensurations corporelles des animaux par rapport à leurs congénères élevés dans les exploitations rurales souligne la baisse des performances pondérales survenue pendant certaines périodes durant lesquelles le programme a connu des contraintes. In southern Senegal, because of tsetse flies, Ndama taurine or Bos taurus taurus is the main bovine breed raised by farmers. The undeniable importance of these cattle in the socio-economic life led to the creation of the Centre de Recherches Zootechniques of Kolda (CRZ-K) and the initiation of a selection program since 1972 to improve animal productivity. The current open breeding nucleus is composed by animals belonging to the CRZ-K and those of farmers Ndama Agro-Breeders' Cooperative (CASE-Ndama). The aim of this study is to phenotypically characterize Ndama taurins of the selection nucleus. The phenotypic data collected for 15 qualitative and 17 quantitative variables was carried out on 118 adult bulls at least four years old. Longitudinal data from 1970 cattle during the period 1973 to 2016 were used to evaluate weight performances. The results showed that the majority of animals had the same appearance with a uniform fawn color, black and white lyre horns and fairly pigmented mucous membranes. Sexual dimorphism was marked. Adult animals had an average height of 106.9 ± 3.5 cm and average weight of 230.9 ± 40.6 kg. The mean of body length and chest perimeter were 112.0 ± 7.9 cm and 150.0 ± 8.4 cm respectively. This study showed the increase in body measurements of animals compared to those in rural farms and highlighted the decline in weight performances occurred during certain periods where the program had constraints

Feasibility of Onchocerciasis Elimination with Ivermectin Treatment in Endemic Foci in Africa: First Evidence from Studies in Mali and Senegal

The control of onchocerciasis, or river blindness, is based on annual or six-monthly ivermectin treatment of populations at risk. This has been effective in controlling the disease as a public health problem, but it is not known whether it can also eliminate infection and transmission to the extent that treatment can be safely stopped. Many doubt that this is feasible in Africa. A study was undertaken in three hyperendemic onchocerciasis foci in Mali and Senegal where treatment has been given for 15 to 17 years. The results showed that only few infections remained in the human population and that transmission levels were everywhere below postulated thresholds for elimination. Treatment was subsequently stopped in test areas in each focus, and follow-up evaluations did not detect any recrudescence of infection or transmission. Hence, the study has provided the first evidence that onchocerciasis elimination is feasible with ivermectin treatment in some endemic foci in Africa. Although further studies are needed to determine to what extent these findings can be extrapolated to other areas in Africa, the principle of onchocerciasis elimination with ivermectin treatment has been established

Annexe 23.2. L’évolution des conditions de travail des enquêteurs de la plateforme de Niakhar

De 1962 à nos jours, les agents locaux de la plateforme de recherche de Niakhar ont vu leurs conditions de travail et leur situation juridique évoluer, sous l’influence de plusieurs facteurs. L’objectif de ce chapitre est de décrire l’évolution de ces conditions juridiques, d’en identifier les principales périodes, et d’expliciter les facteurs qui ont provoqué ces changements. Pour réaliser ce travail, la méthode a reposé sur la collecte de textes et documents et la réalisation d’entretiens a..

Decadal Variability of Rainfall in Senegal: Beyond the Total Seasonal Amount

International audienceAbstract Rainfall characteristics are crucial in monsoon regions, in particular for agriculture. Crop yields indeed depend on the rainfall seasonal amounts, but also on other rainfall characteristics such as the onset of the rainy season or the distribution of rainy days. In the Sahel region, while the average amount of seasonal rainfall has been shown to be marked by strong decadal variability, the modulation of rainfall characteristics has received less attention in the literature so far. In this study, we show that the frequency of light, heavy, and extreme rainfall events and the mean intensity of rainfall events in Senegal exhibit a marked decadal variability over the 1918–2000 period, strongly similar to that of the mean seasonal rainfall. The decadal modulations of these events show a strong and positive link with the Atlantic multidecadal variability (AMV). Indeed, positive sea surface temperature anomalies over the North Atlantic and Mediterranean related to a warm AMV phase are associated with negative sea level pressure anomalies over the northern Atlantic and a northward shift of the intertropical convergence zone. We also find that the onset and cessation dates as well as the length of the rainy season show relatively less decadal variability, which is more related to the interdecadal Pacific oscillation (IPO), a positive phase of the latter leading to a late onset, an early cessation, and an overall shorter rainy season in Senegal

Caractérisation phytochimique et étude de l’activité antimicrobienne d’extraits de feuilles de trois plantes de la flore sénégalaise : Detarium senegalense, Detarium microcarpum et Piliostigma reticulatum

Detarium senegalense, Detarium microcarpum et Piliostigma reticulatum sont trois plantes de la flore sénégalaise, utilisées en médecine traditionnelle pour la prise en charge de maladies infectieuses. Cette étude visait à déterminer in vitro l’activité antimicrobienne d’extraits et de fractions de feuilles de ces plantes sur différentes souches (Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa, Enterococus faecalis, Staphylococcus aureus et Candida albicans). Les méthodes de diffusion en milieu solide et de dilution en milieu liquide ont été utilisées pour la détermination des Diamètres d’Inhibition (DI) et des Concentrations Minimales Inhibitrices (CMI). Le screening phytochimique a été réalisé par des tests de caractérisation reposant sur des réactions physico-chimiques et par chromatographie sur couche mince. Sur l’ensemble des échantillons testés, seule la fraction dichlorométhanique de P. reticulatum était inactive sur les souches bactériennes étudiées. Les DI variaient entre 10 et 23 mm pour les échantillons actifs. Les CMI étaient comprises entre 0,0293 et 2,50 mg/mL. Les fractions d’acétate d’éthyle étaient les plus actives. Les familles de molécules suivantes ont été identifiées : tanins, flavonoïdes et saponosides. Les teneurs en polyphénols totaux variaient de 0,66 à 19 mg équivalent acide tannique/g. Cette étude a montré que les extraits des trois plantes sont dotés d’un fort pouvoir antimicrobien et contiennent plusieurs familles de composés chimiques

Molecular Detection and Genetic Characterization of Two Dugbe Orthonairovirus Isolates Detected from Ticks in Southern Senegal

Dugbe virus (DUGV) is a tick-borne arbovirus first isolated in Nigeria in 1964. It has been detected in many African countries using such diverse methods as serological tests, virus isolation, and molecular detection. In Senegal, reports of DUGV isolates mainly occurred in the 1970s and 1980s. Here, we report a contemporary detection of three novel DUGV isolates upon screening of a total of 2877 individual ticks regrouped into 844 pools. The three positive pools were identified as Amblyomma variegatum, the main known vector of DUGV, collected in the southern part of the country (Kolda region). Interestingly, phylogenetic analysis indicates that the newly sequenced isolates are globally related to the previously characterized isolates in West Africa, thus highlighting potentially endemic, unnoticed viral transmission. This study was also an opportunity to develop a rapid and affordable protocol for full-genome sequencing of DUGV using nanopore technology. The results suggest a relatively low mutation rate and relatively conservative evolution of DUGV isolates

Proof-of-principle of onchocerciasis elimination with ivermectin treatment in endemic foci in Africa: final results of a study in Mali and Senegal.

BACKGROUND: Mass treatment with ivermectin controls onchocerciasis as a public health problem, but it was not known if it could also interrupt transmission and eliminate the parasite in endemic foci in Africa where vectors are highly efficient. A longitudinal study was undertaken in three hyperendemic foci in Mali and Senegal with 15 to 17 years of annual or six-monthly ivermectin treatment in order to assess residual levels of infection and transmission, and test whether treatment could be safely stopped. This article reports the results of the final evaluations up to 5 years after the last treatment. METHODOLOGY/PRINCIPAL FINDINGS: Skin snip surveys were undertaken in 131 villages where 29,753 people were examined and 492,600 blackflies were analyzed for the presence of Onchocerca volvulus larva using a specific DNA probe. There was a declining trend in infection and transmission levels after the last treatment. In two sites the prevalence of microfilaria and vector infectivity rate were zero 3 to 4 years after the last treatment. In the third site, where infection levels were comparatively high before stopping treatment, there was also a consistent decline in infection and transmission to very low levels 3 to 5 years after stopping treatment. All infection and transmission indicators were below postulated thresholds for elimination. CONCLUSION/SIGNIFICANCE: The study has established the proof of principle that onchocerciasis elimination with ivermectin treatment is feasible in at least some endemic foci in Africa. The study results have been instrumental for the current evolution from onchocerciasis control to elimination in Africa

Prevalence and impact of adiposity and sarcopenia during rheumatoid arthritis: rapid and non-invasive evaluation in Sub-Saharan African women

Background: Body composition plays a fundamental role in the occurrence of complications in rheumatoid arthritis. Authors conducted this study, which aimed to determine body composition and its effects on physiological status in African sub-Saharan polyarthritis women.Methods: The anthropometric parameters were measured after an interview and a complete physical examination. The body composition was evaluated using a Tanita® brand bioimpedance meter. Finally, all the patients had a dosage of certain biochemical parameters.Results: An excess of percent fat mass was noted in more than half of women (59.52%) without loss of muscle mass. At the same time, 30% of women had a significant decrease in the percentage of body water. The BMI did not appear to be an adequate proxy for these changes. Visceral fat level was elevated just in 16% of women, however it would be a determinant of physiological aging of subjects. Dual therapy methotrexate and corticosteroid would have varying effects depending on the duration and the dose of treatment. The basic metabolism in polyarthritic subjects would be dependent on two parameters namely muscle mass and inflammatory state.Conclusions: Evaluating changes in body composition quickly, non-invasively and inexpensively is possible. It could be useful in the follow-up of rheumatoid arthritis. Managing these changes can reduce cardiovascular morbidity and mortality in rheumatoid arthritis

Crimean–Congo Hemorrhagic Fever Virus Survey in Humans, Ticks, and Livestock in Agnam (Northeastern Senegal) from February 2021 to March 2022

Crimean–Congo hemorrhagic fever virus (CCHFV) is widespread in Asia, Europe, and Africa. In Senegal, sporadic cases of CCHFV have been reported since 1960. Bordering Mauritania in northeastern Senegal, Agnam is an arid area in the region of Matam where CCHFV is endemic, which harbors a pastoralist community. Given the drought conditions of Agnam, inhabitants are in constant movement with their animals in search of pasture, which brings them into contact with pathogens such as arboviruses. To identify CCHFV in this area, we established a One Health site in order to analyze animal livestock, ticks and human samples collected over a one-year period by qRT-PCR and ELISA. Our analysis showed one (1/364) patient carried anti-CCHFV IgM and thirty-seven carried anti-CCHFV IgG (37/364). In livestock, anti-CCHFV IgG was detected in 13 (38.24%) of 34 sentinel sheep. The risk of CCHFV infection increased significatively with age in humans (p-value = 0.00117) and sheep (p-value = 1.18 × 10−11). Additional risk factors for CCHFV infection in sheep were dry seasons (p-value = 0.004) and time of exposure (p-value = 0.007). Furthermore, we detected a total of three samples with CCHFV RNA within Rhipicephalus evertsi evertsi and Rhipicephalus guilhoni tick species. Our results highlighted the usefulness of a One Health survey of CCHFV in pastoral communities at risk of arboviruses

Summary of main results.

<p>NA: not available.</p